Of the Mecyclothorax muriauxi group species with setal formula 2202, this is the only one with a pronotum that is evenly narrowed basally to the obtuse-rounded hind angles (Fig. 10A). Standardized body length 7.2 mm. Head broad with small eyes; frontal grooves broad, shallow, ill defined mesad eyes, deep and broad only near frontoclypeal suture; antennae elongate, filiform, antennomere 8 length 2.0× breadth; eyes little convex, sharing curvature with broad ocular lobe, ocular ratio 1.36, ocular lobe ratio 0.70. Pronotum subquadrate, moderately transverse, MPW/PL = 1.22; lateral margin moderately constricted before hind angle, MPW/BPW = 1.17; a minute jag at hind angle caused by flat articulatory socket of basal pronotal seta; anterior transverse impression broad, shallow, its outline obscured medially by about eight deep longitudinal strigae each side of midline; lateral margin moderately broad in apical half, broadly explanate and raised before hind angle; laterobasal depression deep, broad and smooth. Elytra broadly quadrate, MEW/HuW = 1.79; striae 1–6 well developed, densely punctate, the punctures expanding the strial breadth, separated along stria by length subequal to their diameter, stria 7 shallower, all striae smooth and complete apically; interval 8 broadly subcarinate, convexly protruded dorsad subapical sinuation; lateral elytral setae 7 + (5–6). Microsculpture on vertex a transverse mesh, sculpticell breadth 2× length, sculpticells more isodiametric on neck; pronotal disc with regular transverse mesh, breadth 2× length, median base with isodiametric sculpticells between punctures; elytral disc with transverse sculpticells, breadth 2–3× length, the sculpticells more deeply margined at elytral apex. Coloration of forebody rufopiceous, pronotal lateral margins and median base rufobrunneous; antennomeres 1–3 rufoflavous, 4–11 rufobrunneous; elytral disc rufobrunneous, the sutural interval rufous near scutellum, rufoflavous apically; femora rufoflavous, tibiae rufoflavous with brunneous cast.

Female reproductive tract. The lone female specimen was not dissected.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hiti el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / claridgeiae / J.K. Liebherr 2013 (black-bordered red label).

The species epithet honors the collector, Dr. Elin Claridge, who collected the specimen during the first and only entomological expedition to Pito Hiti.

The type specimen of this species was collected via application of pyrethrin fog to moss-covered vegetation. Thus within the microhabitat of epiphytic mosses, the beetles may be considered subarboreal in habits.

This is the smallest-bodied species in the Mecyclothorax muriauxi group to possess both lateral and basal pronotal setae; standardized body length 5.1 mm and setal formula 2201. The subquadrate pronotum has sinuate lateral margins and a broad base (Fig. 10B); MPW/PL = 1.20, APW/BPW = 0.78. The vertex of the head has shallow transverse-mesh microsculpture, the sculpticells difficult to discern in reflected light. The neck is covered with a more developed isodiametric mesh. The pronotal disc exhibits an evident transverse mesh, sculpticells 2–3× broad as long, and the discal elytral intervals are covered with a more distinct transverse mesh of the same dimensions.

The single holotype female specimen was collected at 1000 m elevation on Mont Marau.

This is a species characterized by dramatically robust proportions, with the very broadly explanate and upraised pronotal lateral margins expanded to a very broad pronotal base (Fig. 10C). The pronotal hind angles are setose, resulting in a setal formula of 2202. The head has very reduced microsculpture, though distinct transverse grooves emanate onto the frons from the frontal grooves. The pronotal disc is covered by an obsolete transverse mesh that is difficult to trace. The microsculpture of the discal elytral microsculpture is similarly difficult to discern, though subtle iridescence suggests the sculpticells are broader, therefore defining transverse lines. The male aedeagus has a broad, bluntly rounded apex and an elongate flagellar plate, plate length 0.48× the distance from the parameral articulation to the lobe apex (Fig. 13A). Standardized body length 7.6–8.0 mm.

The pronotal configurations of the male type of Mecyclothorax muriauxi and the two female types of Mecyclothorax muriauxioides do not seem diagnosably different to this author, and so the two names are herein considered synonymous. All three specimens possess both apical and subapical elytral setae, though the latter are broken off of the female paratype of Mecyclothorax muriauxioides.

The three specimens of this species have been collected at 1200 and 1300 m elevation on Mont Marau. This species is terricolous, with the 1200 m elevation specimen collected from under rocky debris, and those from 1300 m captured in a vinegar pitfall trap.

This species shares a transverse pronotal configuration (Fig. 10D) with three other species in the group – Mecyclothorax obtusus, Mecyclothorax gerardi, and Mecyclothorax poria (Figs 11A, B, D) – but it is the only one to exhibit a quadrisetose pronotum; setal formula 2202. Also, the elytra are more parallel sided, and the elytral striae more distinctly punctate. The frons and vertex are glossy, with a reduced transverse mesh visible in the frontal grooves. The pronotum has patches of reduced isodiametric to transverse mesh over portions of the disc, and the elytra are covered with dense transverse lines causing iridescence. The male aedeagal median lobe is elongate, with a broadly expanded apex bearing an obtuse dorsal projection (Fig. 3C). Standardized body length 7.1 mm.

The only known specimen was collected in litter at 1000 m elevation, on Pihaaiateta along the ridge to Pito Hiti.

Of the Mecyclothorax muriauxi group species with setal formula 2101 – the others include Mecyclothorax brevipennis and Mecyclothorax quadraticollis (Figs 12B, C) – this species exhibits sinuate pronotal lateral margins and a basal width less than the maximal width; MPW/BPW = 1.12 (Fig. 11A). The pronotum is moderately transverse; MPW/PL = 1.26, and the eyes do not protrude much from the ocular lobe; ocular ratio 1.38. This species is also among the smallest bodied species in the group; standardized body length 5.0 mm. The frons and vertex are covered with a distinct mesh of isodiametric and transverse sculpticells. The pronotal disc bears transverse mesh microsculpture, most visible outside the area of reflected light, and the discal elytral intervals are covered with an elongate transverse mesh, sculpticell breadth 2–3× length.

This species has been collected at l100–1400 m elevation along the Mont Aorai ridge. It is a terricolous species, with one specimen collected in moss, and a second captured in a vinegar pitfall trap.

This species comprises beetles possessing only the posterior supraorbital seta and a transverse, bisetose pronotum; MPW/PL = 1.38 and setal formula 1101. The elytral humeri are distinctly angulate and the elytra are broadly ovoid, the lateral margins convex throughout their length (Fig. 11B). The vertex has transverse mesh microsculpture mesad the frontal grooves, the rows of sculpticells dissected by distinct transverse wrinkles emanating from the grooves. The pronotal disc is covered with a shallow but traceable transverse mesh, and the discal elytral intervals are lined with shallow transverse microsculpture consisting of elongate sculpticells intermixed with transverse lines. The male aedeagal median lobe has a broad apex that is rounded both dorsally and ventrally, and apically flattened (Fig. 13B). The aedeagal internal sac bears an elongate flagellar plate that is slightly more than half as long as the distance from the parameral articulations to the lobe apex, and a broadly distributed ventral ostial microtrichial patch. Standardized body length 5.3–5.4 mm.

The type series was collected from mosses at 1200 m elevation on the Mont Aorai ridge. Subsequently, two individuals were extracted through the use of pyrethrin fog from moss growing on Metrosideros. This second collecting event occurred at 1210 m elevation on Aorai.

The pronotum of this species is uniquely shaped among known members of this species group, with the lateral margins concave anterad slightly projected, acute hind angles (Fig. 13C). The eyes are convex and moderately protruded; ocular ratio 1.48, ocular lobe ratio 0.78. Only the posterior supraorbital and lateral pronotal setae are present, leading to a setal formula of 1101. Microsculpture of the dorsal body surface is well developed, the head with isodiametric and transverse sculpticells mixed in a regular mesh, the pronotal disc with a mixture of shallow isodiametric and transverse sculpticells, and the discal elytral intervals with a shallow transverse mesh, sculpticell breadth 2–3× length supporting indistinct iridescence. Standardized body length 6.0 mm. Head with broad, shallow, ill-defined frontal grooves, transverse wrinkles emanating from the grooves mesally onto frons; antennae short, moniliform, antennomere 8 length 1.55× maximal breadth. Pronotum moderately transverse, MPW/PL =1.33; pronotal base nearly as broad as maximal breadth, MPW/BPW = 1.05; front angles close together, APW/BPW = 0.65, the pronotal margin anteriorly rounded laterad the pronotal juncture with the neck; median base indistinctly depressed relative to disc near midline, more depressed laterally where juncture is marked by indistinct longitudinal wrinkles; laterobasal depression broad, impunctate, explanate lateral margin transversely wrinkled to canaliculate anterad hind angle; anterior transverse impression obsolete, mostly indicated by minute longitudinal wrinkles. Elytra moderately convex, maximally elevated from the depressed scutellum posteriorly to the apex of the parascutellar striole; striae 1–6 moderately incised, finely and regularly punctate throughout much of length, smooth in apical quarter, elytral intervals moderately convex; stria 7 shallow but continuous basally, finely incised, smooth at elytral apex where it is associated with the subcarinate eighth interval, that interval nearly vertically convex dorsad subapical sinuation; lateral elytral setae 7 + 6. Coloration of head capsule evenly rufobrunneous; antennomere 1 flavous, 2 rufoflavous, 3–11 rufobrunneous; pronotal disc dark rufous, anterior portion of lateral depression and laterobasal depression rufoflavous; elytral disc rufobrunneous, the sutural interval pale rufous near scutellum, rufoflavous apically; elytral apex graded to rufoflavous; femora flavous, tibiae flavous with a smoky cast.

Female reproductive tract. The single female specimen as not dissected.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hiti el. 2070 m 2-VI- / 2006 lot 01 pyrethrin fog / 17°36.813'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / jeanyvesi / J.K. Liebherr 2013 (black-bordered red label).

The species epithet honors Dr. Jean-Yves Meyer, botanist extradordinaire, who accompanied Dr. Claridge on the expedition to Pito Hiti. The epithet is derived in a manner parallel to that of Mecyclothorax gerardi – to which this species bears close similarity – as that species was named to honor Gerard H. Perrault, a specialist on Formicidae, Tahitian collecting colleague, and the describer’s brother.

The single specimen was collected in a pyrethrin fog sample of moss-covered vegetation at 2070 m elevation on Pito Hiti, only 40 m elevation below the summit.

Of the four Mecyclothorax muriauxi group species with setal formula 1101 (Figs 11B–D, 12A), this species exhibits the smoothest pronotal median base, which bears 5–8 rounded punctures along the gently sloped juncture with the pronotal disc, and only indistinct transverse wrinkles basally near the pronotal hind margin. The pronotum is broadest basally, the basal width subequal to the width at midlength (Fig. 11D). The eyes are small in diameter, ocular lobe ratio 0.74–0.81 (n = 5), but convex, ocular ratio 1.44–1.50. Standardized body length 5.1–6.2 mm. Head with broad, shallow frontal grooves, fine transverse wrinkles emanating from grooves onto frons; posterior supraorbital seta situated dorsad fine shallow groove lining juncture of ocular lobe and gena; antennae submoniliform, short, antennomere 8 length 1.69× maximal breadth. Pronotum transverse, trapezoidal, the hind angles bluntly obtuse, the margin rounded behind, MPW/PL = 1.31–1.38; lateral margin straight anterad hind angle, but upraised and so appearing slightly sinuate; anterior transverse impression obsolete medially, narrow laterally where it is defined by a finely incised groove; front angles slightly protruded, rounded; lateral marginal depression narrow near midlength, edge beaded to just anterad hind angle. Elytra broad basally, humeri subangulate, lateral elytral margins convex (Fig. 11D); striae 1–5 evident, complete to basal groove, finely punctate in basal half and smooth apically, stria 6 shallower, stria 7 traceable as a series of isolated punctures basally, very shallow, obsolete apically, where it defines mesal border of slightly convex interval 8, that interval only indistinctly subcarinate apicad position of subapical sinuation; discal elytra intervals slightly convex; lateral elytral setae (6–7) + (5–6). Microsculpture obsolete on frons, indistinct isodiametric mesh on neck; pronotal disc with shallow transverse microsculpture, sculpticell breadth 2–4× length; pronotal median base glossy, transverse mesh indistinct; discal elytral intervals covered with mixed elongate transverse mesh and transverse lines. Coloration of vertex rufous; antennomere 1 flavous, 2–3 brunneous with apex flavous, 4–11 darker, brunneous; pronotal disc rufous, the margins broadly rufoflavous; elytral disc rufous, marginal depression and humeral angle rufoflavous; femora flavous with brunneous cast, tibiae slightly more brunneous.

Male genitalia. Aedeagal median lobe blunt apically, with a broadly rounded, slightly convex ventral face and more pointed dorsal projection (Figs 3D, 13C); ostial canal straight, terminated just ventrad the dorsal projection. The five Mecyclothorax muriauxi group species for which males are known all possess similar median lobes, with Mecyclothorax poria, Mecyclothorax gerardi, and Mecyclothorax mapura exhibiting almost identical median lobe apices. The lobe apex of Mecyclothorax poria (Fig. 13C) is narrower dorsoventrally than that of Mecyclothorax mapura (Fig. 13D), and broader and more flattened apically than that of Mecyclothorax gerardi (Fig. 13B). Nevertheless, in these taxa, external characters can better distinguish the taxa.

Female reproductive tract. The bursa copulatrix of Mecyclothorax poria females is broadened basally, with no evidence of a discrete vagina (Fig. 14A). The bursa in the single known female has a smooth surface and a constriction just beyond midlength, and is approximately twice as long as its maximal breadth when compressed under a cover slip. The female basal gonocoxite exhibits an apical fringe of 3–4 setae (Fig. 8B), and approximately eight setae along the medial margin. The apical gonocoxite is broadened basally resulting in a broadly arcuate lateral margin. It bears two parallel-sided lateral ensiform setae, a dorsal ensiform seta, and an apical sensory furrow with two nematiform setae plus two furrow pegs.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Marau road el. 1275 m / 10-IX-2006 lot 02 / 17°36.433'S, 149°32.339'W / pyr. fog horiz. Weinmannia / trunks + veg. J.K. Liebherr // HOLOTYPE / Mecyclothorax / poria / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled: SOCIETY IS: Tahiti / Tahiti Nui Mont Marau / 1280 m el. 6-XI-1999 / D.A. Polhemus pyr. fog / sta. 1 Weinmannia for. // ALLOTYPE / Mecyclothorax / poria / J.K. Liebherr 2013 (black-bordered red label).

Paratypes: same data as allotype (CUIC, 2; NMNH, 1); Tahiti Nui, Mont Marau, Mt. Marau road, 1315 m el., 17°36.433'S, 149°32.333'W, 10-IX-2006 lot 05, Polhemus, pyr. fog mossy Weinmannia w/ Astelia (NMNH, 1)

The species epithet, poria, means fat or corpulent in Tahitian, the epithet signifying the broad outline of the body caused by the basally broadened pronotum and broadly based, laterally convex elytra.

All samples containing this species have come from the Mont Marau ridge between 1275 and 1315 m elevation. All specimens of the type series have been obtained by fogging moss-covered Weinmannia trees, in one instance when an Astelia plant was growing on the Weinmannia tree.

Among Mecyclothorax muriauxi group species with setal formula 1101, this species exhibits the smallest, least convex eyes (Fig. 12A); ocular ratio 1.43, ocular lobe ratio 0.76. As in Mecyclothorax poria, the bisetose pronotum is broadest basally, however in this species the median base is margined by about seven longitudinal strigae along its juncture with the convex disc. The dorsal surface of the head capsule is glossy, with only indistinct sculpticells associated with wrinkles emanating from the frontal grooves. The pronotal disc is covered with a shallow, indistinct transverse mesh, the sculpticell breadth 2–3× length, and the discal elytral intervals exhibit dense transverse microsculpture; a mixture of transverse mesh and transverse lines. The male aedeagal median lobe apex is broadly expanded dorsoventrally, with the ventral surface not expanded from the more basal curvature of the shaft’s ventral surface (Fig. 13D). As in other species in the group, the male flagellar plate is elongate, its length 0.5× the distance from parameral articulations to the flattened apex. Standardized body length 6.1 mm.

The holotype specimen was collected between 900 and 1200 m elevation on Mapura, the ridge NNW of Pihaaiateta of the Pito Hiti-Orohena massif.

This species is characterized by the broadest, most robust body, and the acutely protruded, glabrous, pronotal hind angles (Fig. 12B). The elytra are remarkably broad and foreshortened, with the humerus broadly extended and rounded at the base of the lateral marginal depression. The head is covered with transversely stretched isodiametric sculpticells arranged in transverse rows. The pronotal disc bears a shallow transverse mesh, the sculpticell breadth 2–4× length, and the discal elytral intervals are covered with a well-developed transverse mesh with sculpticell breadth 2–3× length. Setal formula 2101; standardized body length 7.2–8.1 mm.

Perrault collected the female holotype, 20-xii-1977, at 1000 m elevation on Mont Marau. Earlier that same year – 29–30-vi-1977 – another female was collected “at night” from the summit of Marau, 1490 m elevation (W.C. Gagné and S.L. Montgomery; BPBM).

Unique among the Mecyclothorax muriauxi group in the parallel-sided elytra (Fig. 12C), this species can also be diagnosed by the broad head and little convex eyes; ocular ratio 1.40. The pronotum is quadrate with the lateral margins gently concave and upraised anterad the projected, acute hind angles. The discal elytral striae are deep with elongate punctures, the intervals convex. The frons and vertex are distinctly microsculptured, the sculpticells a mixture of isodiametric and transverse. The pronotum bears transverse mesh microsculpture that produces a subiridescent sheen, and the discal elytral intervals are lined with transverse sculpticells, their breadth 2–3× their length. Setal formula 2101; standardized body length 6.1 mm.

The holotype female was beaten from dead leaves at 1400 m elevation on Mont Marau.

Relative to Mecyclothorax fosbergioides, this species can be diagnosed immediately by the reduced microsculpture that results in a glossy dorsum. The pronotum is narrow, MPW/PL = 1.07, and the humeral angles are proximate due to the narrow elytral base, MEW/HuW = 2.36. The male aedeagal median lobe is elongate and narrow, the apex expanded both dorsally and moreso ventrally, with a flattened apical face (Fig. 13E). The male flagellar plate is moderately long, its length estimated at 0.45× the distance from parameral articulations to the apex in the uneverted aedeagus. Setal formula 2222; standardized body length 8.25 mm.

This species is known only from the holotype specimen collected by the botanist F.R. Fosberg, from dead Cyathea fern fronds at 915 m elevation above the floor of Papenoo Valley on the lower flank of Mont Orohena.

The largest bodied Tahitian Mecyclothorax at standardized body length 8.6–8.9 mm, and sharing the lanky proportions of its group mate, Mecyclothorax fosbergi (Fig. 15). However this species is characterized by a broader pronotum, MPW/PL = 1.18, and relatively narrower humeri, MEW/HuW = 2.52, with the elytra more broadly obovate in shape. The head bears shallow isodiametric sculpticells, and the pronotum is covered by a shallow elongate transverse mesh that produces an indistinct iridescence. The discal elytral intervals are covered with a dense, regular mesh, a mixture of isodiametric and transverse sculpticells, the latter twice as broad as long. The male aedeagal median lobe – first reported here – is very similar to that of Mecyclothorax fosbergi (Fig. 13E), although the shaft is somewhat broader (Fig. 13F). Also, the apex is much more elongate and narrower dorsoventrally, though a downturned tip and flattened apical face are shared. The internal sac bears a moderately long flagellar plate, length 0.48× distance from parameral articulations to apical face. Setal formula 2202.

The holotype female was collected by J. Gourvès at 1900 m elevation on Mont Aorai, whereas the male first reported above was collected by E.M. Claridge at 2070 m on Pito Hiti (EMEC). These two localities are an estimated 5.5 km apart taking the ridge distance between them. The microsculpture of the male is somewhat less developed than that of the female holotype. For the present the two specimens are considered conspecific, with the discovery of a male specimen from Mont Aorai the best arbiter for establishing the conspecificity or distinctiveness of the Aorai and Pito Hiti populations.

Among species of the Mecyclothorax altiusculus group, this species stands out based on the narrowly ovate elytra with narrow lateral marginal depressions, and the very shallow elytral striae, the intervening intervals nearly flat (Fig. 16A). The vertex is covered with evident transverse-mesh microsculpture. The surface of the pronotal disc is glossier, though shallowly margined transverse sculpticells are visible outside areas of reflected light, and the discal elytral intervals bear transverse microsculpture, the sculpticells either isodiametric and arranged in transverse rows, or slightly transverse in dimension. Setal formula 2121 in most individuals; of 49 specimens examined, only 1 had paired basal pronotal setae, and a second unilaterally exhibited a seta at the left hind angle (Fig. 16A). The male aedeagal median lobe is evenly narrowed to the apical margin of the ostium, with the apex gently downturned with a rounded tip (Fig. 18A). This simple configuration is closest to the median lobe with more downturned apex observed in Mecyclothorax bryobius (Fig. 19E). Standardized body length 5.8–6.3 mm.

This species was previously known (Perrault 1988) from 1750m and 2000 m elevations on Mont Aorai. More recently – 2-vi-2006 (EMEC) – a single teneral specimen was collected in a pyrethrin fog sample from moss-covered vegetation at 2000 m elevation on Pito Hiti.

This is the broadest bodied species of the Mecyclothorax altiusculus group (Fig. 16B), with a broad pronotum – MPW/PL = 1.29 – and relatively broad elytra standardized by maximum head width; MEW/MHW = 2.45. The elytra are polymorphic for the number of dorsal setae; the left elytron bearing two setae and the right only the anterior seta; thus the setal formula 21(1–2)2. Standardized body length 6.9 mm. Head with broadly convex frons, the frontal grooves narrow posterad and separated from the anterior supraorbital seta by a thin but distinct carina; eyes somewhat bulging dorsally, ocular ratio 1.49, ocular lobe ratio 0.80, the ocular lobe joining the gena at a narrow groove; antennae elongate, filiform, antennomere 8 length 2.33× maximal breadth. Pronotum basally with broadly explanate and upraised lateral margins, the hind angles indicated by a flattened expansion of the margin that looks to all intents and purposes the site for placement of a basal seta (but no seta is present either side); median base distinctly depressed relative to the very convex disc, about 24 small, isolated punctures each side; anterior transverse impression finely, distinctly incised for much of breadth, shallower at midline, with indistinct longitudinal wrinkles crossing anterior callosity; lateral marginal depression narrowest just anterad lateral seta, slightly broader inside broadly rounded front angles, evenly broadened posterad lateral seta to hind angle. Elytra with striae 1–8 deep, complete from basal groove to apex, the discal elytral intervals broadly, moderately convex; the eighth interval broadly carinate apically, extended dorsally above narrowed apex of interval 7, and convexly bulging laterally dorsad the subapical sinuation; lateral elytral setae 7 + 6; apical elytral seta present just laterad stria 2 as it nears stria 7, and subapical elytral seta present in stria 7 just laterad terminal fusion of striae 3 + 4. Microsculpture of vertex reduced, surface glossy, indistinct transverse mesh on neck; pronotal disc glossy, median base mostly glossy but shallow transverse mesh in parts between punctures; discal elytral intervals with a transverse mesh, the sculpticell breadth 2–4× length, mixed with transverse lines, the microsculpture resulting in a coppery reflection. Coloration of head dark rufous; antennomere 1 flavous, 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufopiceous, lateral marginal depression anterad lateral seta rufobrunneous, median base rufous; elytral disc rufopiceous, the sutural interval basally rufous and apically rufoflavous, lateral marginal depression rufobrunneous; femora rufoflavous with brunneous cast, tibiae rufobrunneous with smoky cast most developed in apical half.

Male genitalia. Aedeagal median lobe dorsoventrally expanded apically, with a slightly convex ventral expansion and blunt dorsal tooth (Fig. 18B); ostial canal straight, terminated just ventrad the blunt dorsal tooth; internal sac bearing a large, melanized flagellar plate (Fig. 18C), plate length 0.67× distance from parameral articulations to apical face, with dorsal plate surface bearing elongate gonopore opening; internal sac with broad ventral ostial microtrichial patch and small dorsal ostial microtrichial patch.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / aano / J.K. Liebherr 2013 (black-bordered red label).

The species epithet aano means wide or extensive in Tahitian, the name signifying the very broad body characteristic of this species.

This species is known only from the holotype obtained in a pyrethrin fog sample of moss-covered vegetation at 2000 m on Pito Hiti.

This species is diagnosable within the species group by the broadly reflexed lateral margins of the pronotum and elytra, the explanate and laterally reflexed margins extending the lengths of both structures (Fig. 16C), and the well-defined and complete transverse pronotal impression. The elytral striae are finely incised, and minutely punctate in their basal third, the punctures at most causing a slight expansion of the striae. The eighth elytral interval is upraised and finely carinate dorsad the apical half of the posterior series of the lateral elytral setae, and is broader and more convexly upraised dorsad the subapical sinuation. The vertex bears shallow isodiametric microsculpture, the sculpticells more upraised near the pronotal margin. The pronotal disc bears a shallow, elongate transverse mesh mixed with transverse lines, and the discal elytral intervals are covered with a distinct mesh composed of isodiametric sculpticells in transverse rows and transverse sculpticells. The male aedeagal median lobe is gracile basally, and bears a large dorsal projection at its apex (Fig. 18D). The ostial canal is curved ventrally near its apical terminus. Setal formula 2122; standardized body length 5.9–7.1 mm.

Perrault’s (1988) summarized locality data restricted this species to the elevational range of 1000–1400 m on Mont Marau. This elevational range was also observed in 2006, when this species was repeatedly captured in Malaise traps set at 1170 and 1340 m, but not at lower elevations nor at the summit; 1493 m elevation. Collections of this species in Malaise traps indicate the beetles are good climbers, most likely active on vegetation during nighttime foraging.

Like Mecyclothorax hamatus, but with the anterior transverse impression of the pronotum shallow, broad, and indistinct medially. The pronotal and lateral elytral depressions are broadly reflexed throughout their length (Fig. 16D). The discal elytral striae 1–4 are distinctly punctate in their basal half, the punctures expanding the striae. The eighth elytral interval is upraised and finely carinate dorsad the apical half of the posterior series of the lateral elytral setae, becoming broader and more convexly upraised apically. The frons is glossy with indistinct isodiametric to transverse sculpticells, and the vertex including the neck impression is covered with a regular mesh of isodiametric sculpticells in transverse rows. The pronotal disc is covered with a shallow but regular transverse mesh resulting in a subiridescent sheen, and the discal elytral intervals bear an isodiametric mesh, the sculpticells partially arranged in transverse rows. The male aedeagal median lobe is gracile, and the apex is gently expanded ventrally, moreso dorsally in the shape of a blunt tooth (Fig. 18E). The ostial canal is curved ventrally at its apical terminus. Setal formula 2122; standardized body length 5.8–7.0 mm.

The type series (Perrault 1988) was composed of specimens variously recorded from localities ranging 1100–1400 m and 1000–1800 m elevation on Mont Aorai. Subsequent records include samples from decayed fronds of Freycinetia piled on the ground after trail clearing, and from beating live and dead fern fronds. These latter samples spanned 1255–1320 m elevation.

This species is uniquely characterized by a large tuberculate projection that distorts and upraises the eighth elytral interval and seventh stria, dorsad and immediately anterad the subapical sinuation (Fig. 17A). The seventh stria is present fore and aft the tubercle, but absent on its highest portion. The eyes are less convex and smaller in diameter than those of other Mecyclothorax altiusculus group species; ocular ratio 1.45, ocular lobe ratio 0.77. The head is glossy, and the vertex is covered with shallow but regular isodiametric-mesh microsculpture. The pronotal disc is similarly glossy, but shallow transverse-mesh microsculpture is evident. The discal elytra intervals are covered with a distinct transverse mesh, mixed with transverse lines. In the single known specimen, partially compromised eclosion resulted in a right elytron with a shagreened surface. The withered right elytron bears two dorsal setae, the normally eclosed left elytron only the anterior dorsal seta. Setal formula 21(1–2)2; standardized body length 6.4 mm.

The single female specimen was collected near the summit of Mont Aorai at 1900 m elevation.

This species is best diagnosed by the pronotal lateral depressions that are narrowly reflexed anterad the lateral seta, and the narrowly incised, distinctly punctate discal elytral striae (Fig. 17B). The lateral elytral depressions are only moderately broad, such that the distance between the first three lateral elytral setae of the anterior series and the elytral margin is less than the breadth of elytral interval 9 at the posterior end of that series. The eighth interval is finely carinate dorsad the middle of the posterior series of lateral elytral setae and more upraised and broadly rounded dorsad the subapical sinuation. The vertex of the head is covered with isodiametric-mesh microsculpture arranged in transverse rows. The pronotal disc is glossy medially, with an indistinct transverse mesh laterally and basally, the sculpticells 2–3× broad as long. The discal elytral intervals are lined with a distinct transverse mesh, sculpticell breadth 2–4× length, the microsculpture producing an iridescent silvery sheen. The male aedeagal median lobe is gracile, with a slightly expanded, angular apex (Fig. 18F). The ostial canal curves dorsally only slightly near its apical terminus. Setal formula 2122; standardized body length 7.0–7.2 mm.

This species is recorded from Mont Teatara, Tahiti Iti, between 900 and 1100 m elevation. Two male specimens collected in 2006 have associated ecological data; one was found in association with dead, fermenting Freycinetia, and the second was collected from the wet decayed cambial layer of a dead Reynoldsia plant. The dead Reynoldsia also housed numerous cillaeine Nitidulidae adults and larvae (C.P. Ewing pers. comm.).

This is a gracile species with a narrow orbicular prothorax, MPW/PL 1.25 (Fig. 17C). The lateral marginal depression is of subequal breadth from the rounded hind angle to the lateral seta. The eighth interval is broadly bulging and subcarinate dorsad the subapical sinuation, but not at all elevated anteriorly. The subapical elytral seta is absent, resulting in a setal formula of 2121. The head is glossy with only indistinct sculpticells traceable near the frontal grooves. The pronotal disc is glossy, with micropunctures visible but no sculpticells. The discal elytral intervals are covered with a regular isodiametric mesh. The male aedeagal median lobe appears very similar to that of Mecyclothorax paraltiusculus (Figs 18F, G), but the apex extends less beyond the ostium, and the flattened apical face is less oblique (Fig. 18G). Standardized body length 5.5–5.6 mm.

This species’ known distribution ranges 1100–1400 m elevation on Mont Marau. One specimen was collected in a Malaise trap, indicating the well-developed climbing abilities, and a second was beaten from a mix of Dicranopteris and other ferns.

Beetles of this species appear superficially similar to, and are distributed sympatrically with those of Mecyclothorax altiusculoides (Fig. 16D), but they exhibit pronotal lateral marginal depressions that are apically narrowed, and elytral lateral marginal depressions that are only narrowly reflexed (Fig. 17D). The discal elytral striae 1–6 are deeply and narrowly incised, and are lined with elongate punctures along their basal half, the punctures causing crenulations along the strial length. The eighth interval is finely carinate dorsad the posterior series of the lateral elytral setae, and gradually toward the elytral apex where the interval is broadly convex. The frons and vertex are covered with dense transverse lines that are progressively replaced by an isodiametric mesh near the pronotal juncture. The pronotal disc is glossy medially, with an elongate, partially confused transverse mesh laterally; and the discal elytral intervals are covered with isodiametric sculpticells arranged in transverse rows. The male aedeagal median lobe is very similar to those of Mecyclothorax paraltiusculus and Mecyclothorax pseudaltiusculus (Figs 18F, G), but has a slightly more slender shaft, and an apex with a more acute ventral tip, a flatter apical face, and a more ventrally curved ostial canal (Fig. 19A). Setal formula 2122; standardized body length 5.5–6.5 mm.

This species is known to occupy habitats on Mont Aorai from 1255 to 1940 m elevation. All associated ecological data place it in the axils of dead, decaying Freycinetia fronds, where is occurs microsympatrically with Mecyclothorax altiusculoides.

This and the following species, Mecyclothorax parovalipennis, are intermediate in pronotal configuration for the Mecyclothorax altiusculus group in that the pronotal hind angle apex is rounded, but the pronotal margin anterad the angle is slightly sinuate thereby tightly defining the angle (Figs 20A, B). The elytra are ellipsoid, as in Mecyclothorax jarrigei (Fig. 16A), but the striae are deep and broad (Fig. 20A), with minute punctures basally that only slightly expand the strial breadth. The discal elytral intervals are slightly convex. The microsculpture of the frons is reduced, the surface glossy, though shallow transverse-mesh microsculpture is visible on the neck impression to the pronotum. The pronotal disc is also glossy, though an distinct transverse mesh is visible in the larger wrinkles of the surface. The discal elytral intervals bear an elongate transverse mesh mixed with transverse lines. The male aedeagal median lobe apex is a rounded knob that is slightly extended dorsally (Fig. 19B). The ostial canal is broad and sinuously curved downward at its apical terminus. Setal formula 2122; standardized body length 5.6–5.7 mm.

This species is known from between 1125 and 1400 m elevations on Mont Marau. It has been collected by beating dead tree fern fronds, rotten Freycinetia stalks, and by pyrethrin fogging moss-covered Weinmannia trees.

Like Mecyclothorax ovalipennis, this species is characterized by rounded hind angles that are bordered anteriorly by a slightly sinuate lateral margin (Figs 20A, B). The discal elytral striae are basally punctate, the punctures elongate and laterally expanding the striae, and the discal elytral intervals are nearly flat, even depressed in association with the microsculpture over portions of the intervals (Fig. 20B). The microsculpture is more well developed than in Mecyclothorax ovalipennis, with: 1, the frons bearing patches of transverse-mesh microsculpture and the neck impression with well-developed isodiametric sculpticells; 2, the pronotal disc covered with a shallow but evident transverse mesh; and 3, the discal elytral intervals lined with distinct transverse microsculpture comprising areas ranging from slightly transverse sculpticells to areas of transverse lines. The male aedeagal median lobe apex is broader than that of Mecyclothorax ovalipennis (Fig. 19B, C), and the apical face is more flattened. Setal formula 2122; standardized body length 5.9 mm.

This species is known only from the two type specimens collected at 1900 m elevation near the summit of Mont Aorai.

This species is placeable in the Mecyclothorax altiusculus group based on the convex pronotal lateral margin anterad the narrowly denticulate, glabrous hind angle (Fig. 20C). However it is unique among Tahitian species in the broadly downturned male aedeagal median lobe apex (Fig. 19D). Among this group’s species, a downturned lobe apex, though narrower, is observable in Mecyclothorax bryobius, Mecyclothorax ballioides, and Mecyclothorax ferruginosus (Figs 19E–G). The absence of the anterior supraorbital seta, and the resultant setal formula of 1121, is uncommonly observed in Tahitian Mecyclothorax, with the exceptions of the Mecyclothorax globosus group species, Mecyclothorax vaifaufa Perrault and Mecyclothorax profondestriatus. However their very different aedeagal configurations (Figs 40C, D) give cold comfort to any hypothesis proposing a close phylogenetic relationship. The vertex is glossy, with the neck bearing indistinct isodiametric sculpticells. The pronotal disc is also glossy, with an indistinct transverse mesh visible outside the area of reflected light. The discal elytral intervals are covered with well-developed transverse lines, with only occasional cross-connections resulting in a subiridescent surface. Standardized body length 4.1 mm.

This species was collected at 1100 m elevation on Mont Mauru in association with moss-covered Myrsine and Metrosideros plants.

This species is among the five Mecyclothorax altiusculus group species characterized by a basally narrowed pronotum with briefly sinuate lateral margins (Figs 20D, 21), though the narrowed pronotal base of this species – MPW/BPW = 1.72–1.81 (n = 5) – is similar only to that seen in Mecyclothorax bryobius. The elytra are ovate, with maximum breadth near midlength. The discal elytral striae are finely incised and punctate basally, and the discal intervals are slightly but broadly convex. The frons is glossy, and the neck bears a shallow mesh of transversely stretched microsculpture. The pronotal disc is covered with a shallow transverse mesh, visible outside areas of reflected light. The discal elytral intervals have regular transverse-mesh microsculpture, sculpticell breadth 2–3× length. The male aedeagal median lobe apex is dramatically downturned, with the ventral extension more elongate (Fig. 3H) than observed in the other group species exhibiting a ventral extension (Figs 19D–G). Setal formula 2121; standardized body length 4.5–5.3 mm.

This species has been found from 900–1165 m elevation on Mont Teatara, Tahiti Iti. Specimens have been obtained by beating dead and living fern fronds, within the axils of Astelia plants, and via pyrethrin fogging of horizontal, moss-covered Weinmannia logs.

This species is similar to Mecyclothorax bryobioides, but is easily distinguished by the obovate elytra, the maximal breadth well behind midlength (Fig. 21A), and the more rounded pronotal hind angles. The pronotal base is similarly narrow; MPW/BPW = 1.78–1.89 (n = 3). The microsculpture is more developed than in Mecyclothorax bryobioides, with the frons and vertex covered with a shallow isodiametric mesh, the pronotal disc bearing a regular though shallow transverse mesh, and the discal elytral intervals lined with an elongate transverse mesh mixed with areas of transverse lines. The male aedeagal median lobe is downturned apically (Fig. 19E), but more broadly and much less extensively than in Mecyclothorax bryobioides (Fig. 3H). Setal formula 2121; standardized body length 4.8–5.2 mm.

This species’ known distribution is restricted to the highest elevations on Mont Aorai; 1650–2000 m. It has been collected by beating moss on trees and shrubs, indicating that the species possesses at least partially arboreal habits.

Beetles of this species are similar to those of Mecyclothorax bryobioides (Fig. 20D), however the pronotum is less constricted basally – MPW/BPW = 1.60–1.73 (n = 5) – and the elytra are more broadly ovoid (Fig. 21B). The pronotal hind angles are sharply obtuse, with the pronotal lateral margins subparallel to convergent immediately anterad the angles. The pronotal margin is beaded both laterad and basad the hind angle, the bead broadest immediately inside the hind angle. The discal elytral striae are shallow and distinctly punctate basally, the punctures appearing isolated due to the shallow depth of the striae. The frons and vertex are glossy with indistinct transverse wrinkles. The pronotal disc bears indistinct transverse-mesh microsculpture, the sculpticell margins not visible in areas of reflected light, and the discal elytral intervals bear a distinct mesh composed of both isodiametric and transverse sculpticells, the sculpticells arranged in irregular transverse rows. The male aedeagal median lobe has an evenly arcuate shaft and a short apex with an abrupt ventral extension that has a tightly rounded tip (Fig. 19F). Setal formula 2121; standardized body size 4.0–4.4 mm.

This species has been collected from 1125–1490 m elevation on Mont Marau, always in association with ferns. These situations include beating dead Cyathea tree fern fronds, or collection onto sheets via application of pyrethrin fog to banks of dead or living low-stature ferns.

Befitting its name, this species is characterized by the palest cuticle observed in all Tahitian Mecyclothorax (Fig. 21C). The male aedeagus of one of the two known specimens does not appear particularly teneral (Fig. 19G), though the flavous cast suggests the individual had not become completely melanized when collected. Beyond the coloration, this species can be told by the transverse, basally constricted pronotum; MPW/PL = 1.33, MPW/BPW = 1.75. The pronotal hind angles are distinct, nearly right, and projected, with the pronotal lateral margins convergent immediately anterad the angles. The discal elytral striae are nearly smooth, and are lined with minute punctures that cause slight irregularities in the striae in their basal half. The head is glossy with patches of transverse mesh microsculpture in depressed wrinkles associated with the frontal grooves. The pronotal disc is covered with an indistinct elongate transverse mesh that results in slight iridescence. The discal elytral intervals are covered with a dense transverse-mesh microsculpture, sculpticell breadth 2–4× length. The male aedeagal median lobe apex has an elongate ventral extension (Fig. 19G), most similar, to though not as exaggerated as, that observed in Mecyclothorax bryobioides (Fig. 3H). Setal formula 2122; standardized body length 5.8–6.0 mm.

Georges Perrault collected the two known specimens together between 800 and 1000 m elevation on Mont Teatara, Tahiti Iti.

Beetles of this species appear quite similar to those of the sympatrically distributed Mecyclothorax ferruginosus, however consistent differences in proportions and punctation demonstrate that they are distinct. In this species, the pronotum is less transverse, MPW/PL = 1.25, and less constricted basally, MPW/BPW = 1.59. The elytra are more narrowly ovoid (Fig. 21D), with the lateral margins more narrowly rounded laterad the angulate humeri. The discal elytral striae are more distinctly punctate, with the punctures in striae 1-3 expanding the strial breadths adjacent to the anterior dorsal elytral seta. The frons and vertex are covered with an indistinct transverse mesh, the pronotal disc surface is partially glossy, with areas of transverse-mesh microsculpture, and the discal elytral intervals are covered with transverse lines irregularly joined into an elongate mesh. Setal formula 2122; standardized body length 5.0–5.2 mm.

This species is known from two female specimens collected between 800 and 1000 m elevation on Mont Teatara, Tahiti Iti.

Of the four species in this group with shallow elytral striae (Figs 22A–D), this species is characterized by the most quadrate pronotum; MPW/PL = 1.16–1.20 (N = 2). The pronotal base is relative broad; MPW/BPW = 1.42. This species also exhibits the darkest, most metallic dorsal body coloration. This comprises a forebody that is a rich rufobrunneous with melanized regions near internal apodemes – clypeus, frontoclypeal suture, and pronotal anterior transverse impression and median base – and rufopiceous elytra with narrowly paler sutural intervals and narrowly rufobrunneous lateral marginal depressions. The upraised elytral microsculpture, a mixture of isodiametric and slightly transverse sculpticells, results in a silvery metallic reflection. Setal formula 2222; standardized body length 5.5–5.9 mm. Head with frontal grooves sinuously canaliculated, slightly convergent toward frontoclypeal suture, with distinct transverse wrinkles radiating onto frons from fine carina mesad anterior supraorbital seta; eyes convex, ocular ratio 1.58–1.62, ocular lobe protruded from gena, a fine shallow groove at juncture; antennae filiform, antennomere 8 length 2.0× maximal breadth. Pronotum with obtuse, setose hind angles, the flattened area surrounding the setal articulatory socket protruded as a jag that comprises angle; median base smooth near midline, convexly raised above basal margin and depressed relative to convex disc, juncture with disc lined with 10–12 fine, short longitudinal wrinkles each side; anterior transverse impression bordered anteriorly by a raised margin, crossed by about eight fine longitudinal strigae each side. Elytra moderately convex, the elytral striae very shallow and indistinctly punctate, the striae so shallow that punctures are intermittently isolated even on disc, intervals only slightly convex; humeri obtuse angulate, the lateral marginal depression narrow throughout length; eighth interval convexly raised, subcarinate only near elytral apex, coplanar with other intervals basad subapical sinuation; lateral elytral setae 7 + (5–6). Microsculpture of frons and vertex a well-developed transverse mesh; pronotal disc covered with a shallow transverse mesh, the sculpticells visible only outside areas of reflected light. Coloration of body dorsum somber; antennomeres 1–2 rufoflavous, 3–11 rufobrunneous; femora flavous except for apices with rufoflavous cast, contrasted with partially melanized, rufobrunneous ventral sclerites; tibiae and tarsi rufopiceous.

Male genitalia. Aedeagal median lobe robust, shaft broad; apex moderately extended beyond ostium, tip gently downturned (Fig. 24A); right paramere narrow in apical half of length, extended as a whip-like structure; internal sac with broad ventral expansion that is covered with a well-developed ventral ostial microtichial patch; flagellar plate very elongate, length 0.70× distance from parameral articulations to apex.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hiti el. 2080 m 2-VI- / 2006 lot 03 pyrethrin fog / 17°36.806'S, 149°27.842'W / E. M. Claridge // HOLOTYPE / Mecyclothorax / papau / J.K. Liebherr 2013 (black-bordered red label).

Paratype: Tahiti Nui, Pito Hiti, 2090 m el., 17°36.790'S, 149°27.842'W, 2-vi-2006 lot 02, Claridge, pyrethrin fog (EMEC, 1 teneral female).

The species epithet papau is the Tahitian adjective for shallow, as well as the noun for shallows. The name signifies the very shallow elytral striae observed in individuals of this species.

The two specimens were collected in pyrethrin fog samples of moss-covered vegetation 20–30 m elevation below the summit of Pito Hiti.

Like Mecyclothorax papau in the very shallow elytral striae and rufopiceous elytra with a metallic reflection, but with more narrowly ellipsoid elytra, and a more transverse and more basally constricted pronotum, MPW/PL = 1.31, MPW/BPW = 1.47 (Fig. 22B). The head and pronotum are concolorous, dark rufobrunneous, without fields of melanized cuticle as in Mecyclothorax papau. Setal formula 2222; standardized body length 6.0 mm. Head with sinuously canaliculated frontal grooves, the frons with a few indistinct wrinkles on the mesal slopes of the grooves; eyes moderately convex, ocular ratio 1.57, the ocular lobe protruded and margined behind by a distinct groove, ocular lobe ratio 0.88; antennae filiform, antennomere 8 length 2.25× maximal breadth. Pronotum with rounded hind angles, the basal seta producing a jag in the margin that is 0.10× the pronotal length anterad the basal margin; median base depressed relative to convex disc, 8–11 fine punctures each side, punctures smaller and more isolated medially, 5–8 elongate punctures along margin with disc; anterior transverse impression broad and shallow but complete medially, finely incised anteriorly only in lateral half of each side; lateral marginal depression of even breadth in anterior half of pronotum, not broader at front angle. Elytra narrowly rounded basally, the proximate humeri angled; striae 1–6 shallow and partially discontinuous on disc, punctures best developed on striae 1 and 2, stria 7 visible only as a discontinuous series of elongate depressions; eighth interval only slightly upraised laterad stria 7 from above subapical sinuation to apex; lateral elytral setae 7 + (5–6). Microsculpture of frons and vertex a shallow transverse mesh. Pronotal disc with an elongate transverse mesh visible outside areas of reflected light, the sculpticell breadth 4× length, and discal elytral intervals with a distinct, regular transverse mesh, sculpticell breadth 2–3× length. Coloration of antennomere 1 flavous, antennomeres 2–7 or 8 rufobrunneous, and antennomeres 8 or 9–11 rufoflavous; ventral body sclerites rufobrunneous, contrasted to dorsally flavous elytral epipleuron and flavous femora; tibiae and tarsi rufobrunneous.

Female reproductive tract. The female holotype was not dissected, but the gonocoxae are exerted and therefore visible. Basal gonocoxite 1 with apical fringe of 2–3 setae laterally, and 4–5 smaller setae along medial margin including apex; apical gonocoxite 2 with two lateral ensiform setae, the apical lateral seta stouter but of the same length as the basal seta, and a single dorsal ensiform seta as broad as the apical seta; apical sensory furrow bearing two nematiform setae.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hiti el. 2110 m 2-VI- / 2006 lot 04 pyrethrin fog / 17°36.860'S, 149°27.837'W / E. M. Claridge // HOLOTYPE / Mecyclothorax / manina / J.K. Liebherr 2013 (black-bordered red label).

The species epithet is the Tahitian word mānina, meaning smooth, polished, or unwrinkled, signifying the smooth polished elytra observed in the holotype.

This was the sole specimen collected on the actual summit of Pito Hiti, 2110 m elevation. It was found via pyrethrin fogging of moss-covered vegetation. Only 30 m lower in elevation, the same collecting technique resulted in specimens of Mecyclothorax papau, Mecyclothorax everardi, Mecyclothorax pitohitiensis, Mecyclothorax hoeahiti sp. n., and Mecyclothorax paraglobosus Perrault.

Among the Mecyclothorax dannieae group, this species shares the moderately impressed elytral striae and paler body margins observed in beetles comprising Mecyclothorax brittoni (Figs 22C, D), however the discal elytral striae 2–4 are at most irregularly impressed in their basal half, not punctate. This species exhibits a smaller standardized body length – 4.7–5.3 mm – than the preceding Mecyclothorax papau and Mecyclothorax manina. Setal formula 2222. Head with very fine, sinuous frontal grooves, their mesal slopes very shallowly wrinkled; eyes convex, ocular ratio 1.50–1.59 (n = 5), ocular lobe protruded with broad shallow groove at genal juncture; antennae shorter, submoniliform, antennomere 8 length 1.8× maximal breadth. Pronotum transverse, MPW/PL = 1.22–1.31, moderately constricted basally, MPW/BPW = 1.39–1.46; basal setal articulation in expanded margin resulting in small jag, the jag anterad slightly convex basal margin and so seta appears to be located at hind angle; median base moderately depressed relative to disc, irregularly punctured but with distinct longitudinal strigae lining margin with disc; anterior marginal impression shallow, broad, but crossed by 6–7 indistinct longitudinal wrinkles each side of midline; lateral marginal depression narrow, margin upraised near midlength, slightly broader and margin less upraised at front angle. Elytra broadly rounded basally, slightly obovate with greatest width behind midlength; humeri tightly rounded with basal groove distinctly recurved between the bases of striae 1–4; striae 1–6 broad, shallow on disc, irregularly impressed along length, stria 7 shallower basally; interval 8 only slightly elevated laterad apex of stria 7, its surface of same convexity as interval mesad stria 7; lateral elytral setae 7 + 6. Metathoracic wings reduced to vestigial flaps that do not extend beyond posterior margin of metanotum. Microsculpture of frons and vertex a distinct transverse mesh, sculpticell breadth 2× length, neck with isodiametric mesh; pronotal disc with well-developed microsculpture, a mixture of isodiametric and transverse sculpticells in transverse rows; discal elytral intervals with a regular, shallowly margined transverse mesh, sculpticell breath 2× length, the sculpticells shiny in reflected light. Coloration of frons and vertex rufobrunneous with metallic reflection; antennomeres 1–3 rufoflavous, 4–11 with brunneous cast; pronotal disc rufobrunneous with silvery metallic reflection, lateral margins, base and anterior callosity rufoflavous; elytral disc with intervals 2–6 dark brunneous with a metallic reflection, intervals 7–9 rufoflavous, sutural stria rufobrunneous basally, rufoflavous near apex; femora flavous, tibiae rufoflavous.

Male genitalia. Aedeagal median lobe shaft moderately slender, the apex beyond the ostium recurved first ventrally then dorsally, the apex expanded dorsoventrally, moreso ventrally, and flattened as an apical face (Fig. 24B); right paramere moderately broad, parallel sided nearly all the way to the tip; ostial canal on right face of median lobe and evenly curved in parallel with dorsal surface.

Female reproductive tract. Bursa copulatrix curved and folded to the right apically, length about 2× maximal breadth compressed on microslide (Fig. 14B); basal gonocoxite 1 broad, with apical fringe of four setae each side, approximately 10 small setae on mesal half of coxite; apical gonocoxite 2 broad basally, lateral margin broadly arcuate (Fig. 8D), two lateral ensiform setae with maximal breadth medially along length, one dorsal ensiform seta, and apical sensory furrow with two nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hiti el. 2070 m 2-VI- / 2006 lot 01 pyrethrin fog / 17°36.813'S, 149°27.842'W / E. M. Claridge // HOLOTYPE / Mecyclothorax / everardi / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled as holotype.

Paratypes: same data as holotype (CUIC, 2; EMEC, 3); Tahiti Nui, Pito Hiti, 2000 m el., 17°36.790'S, 149°27.842'W, 2-vi-2006 lot 02, Claridge, pyrethrin fog (CUIC, 3; EMEC, 8; MNHN, 2; NMNH, 2), 2080 m el., 17°36.806'S, 149°27.842'W, 2-vi-2006, lot 03, Claridge, pyrethrin fog (CUIC, 2; EMEC, 2).

Based on synapomorphies of the body coloration and male genitalia, this species is hypothesized to represent the adelphotaxon of Mecyclothorax brittoni. As such, the species epithet everardi places E.B. Britton’s first name adjacent to his last name in any phylogenetic classification of Mecyclothorax. The species epithet honors Dr. Britton’s many efforts in the study of Pacific Mecyclothorax beetles, as well as his subsequent illustrious career at C.S.I.R.O., Canberra.

All specimens have been collected from 2000 to 2080 m elevation on Pito Hiti via pyrethrin fogging of moss-covered vegetation.

Individuals of this species share the pale elytral margins and sutural interval surrounding piceous elytral discs with Mecyclothorax everardi (Figs 22C, D), but the elytral humeri are closer together and the elytral base is more rounded laterad the humeral angles. The microsculpture is more well developed, with the head covered with upraised, transversely stretched sculpticells resulting in a shagreened appearance. The pronotum has a well-developed isodiametric mesh anteriorly amongst the longitudinal wrinkles crossing the anterior transverse impression. The pronotal disc is covered with an evident transverse mesh, and the discal elytral intervals bear a well-developed transverse mesh, sculpticell breadth 2–3× length. The male aedeagus (Fig. 24C) has an expanded median lobe apex, though the apex is less curved dorsally than observed in males of Mecyclothorax everardi (Fig. 24B). The right paramere is moderately broad and parallel sided nearly all the way to the pointed parameral tip. The ostial canal runs parallel to the dorsal margin of the aedeagus apicad the ostium on the right face of the median lobe, curving ventrally just before its apical terminus. Setal formula 2221; standardized body length 4.8–5.2 mm.

This species is known from two male specimens collected at 1900 m elevation near the summit of Mont Aorai.

Beetles of this species (Fig. 22E) look like smaller-sized versions of those comprising the sympatric Mecyclothorax teatara (Fig. 23D), but the presence of only the posterior supraorbital seta diagnoses this species from all others in the Mecyclothorax dannieae group; setal formula 1221; standardized body length 4.6–4.8 mm. The pronotum is more transverse than that of Mecyclothorax teatara; MPW/PL = 1.27–1.30 (n = 2) in this species versus MPW/PL = 1.25 (n = 2) in Mecyclothorax teatara. Head with frontal grooves subparallel, shallow behind with small transverse wrinkles emanating onto frons, broad and deep anteriorly near the frontoclypeal suture; eyes moderately convex on little protruded ocular lobes, ocular ratio 1.44–1.51, ocular lobe ratio 0.83–0.86, a broad shallow groove at juncture of gena and hind portion of lobe; antennae moderately elongate, antennomere 8 length 1.80× maximal breadth. Pronotum transverse, lateral margins broadly convex from tightly rounded, little protruded front angles to obtuse-rounded hind angles; basal pronotal setal articulation causing jag in margin and a very brief sinuation anterad the seta; median base moderately depressed relative to disc, very smooth, with 6–9 sparsely distributed, shallow punctures each side, margin of base and disc lined with elongate punctures and fine longitudinal wrinkles; basal pronotal margin broadly convex between the hind angles; anterior transverse impression complete medially, anterior margin upraised at anterior callosity, impression crossed by 3–7 longitudinal wrinkles each side in median 2/4s, the wrinkles variously continued across the anterior callosity; apical width noticeably less than width across hind angles, APW/BPW = 0.81–0.85; lateral marginal depression moderately narrow, the margin upturned, depression not wider inside front angles; laterobasal depression very smooth, broad, broadly margined laterally and basally, evenly upraised anteriorly to meet disc. Elytra broadly ovate, basal groove evenly curved, humerus tightly rounded, and lateral margin broadly extended posterad humerus; disc flat between the third intervals each side, sides moderately sloped to lateral marginal depression; discal elytral striae 1–5 moderately deep, smooth, the associated intervals broadly, slightly convex, striae 6–7 slightly shallower, minutely punctate; apex with striae 1–6 moderately deep, stria 7 deeper and broader apicad subapical sinuation, interval 8 no more convex than inner intervals; lateral elytral setae 7(8) + 6. Microsculpture of vertex a shallow, transverse mesh, sculpticell breadth 2–4× length; pronotal disc with elongate transverse mesh, sculpticell breadth 3–5× length, intermixed with transverse lines; pronotal median base with evident transverse mesh, breadth 2× length, on the flat cuticle among the punctures; elytral disc with distinct transverse mesh, sculpticells 2× broad as long, plus transverse lines. Coloration of head rufous with a piceous cast, clypeus rufous, labrum rufoflavous; antennomere 1 flavous, 2–4 rufoflavous; 5–11 rufobrunneous; pronotal disc rufobrunneous, median base and anterior callosity concolorous, lateral marginal depressions slightly paler; elytral disc rufous with a silvery metallic reflection, apex narrowly flavous, lateral marginal depression rufoflavous outside the lateral elytral setal series; femora rufoflavous with subtle smoky cast medially, tibiae rufoflavous with brunneous cast.

Male genitalia. Aedeagal median lobe broad in basal half, evenly narrowed to apex of ostium, lobe apex narrowly extended beyond ostium, expanded into a narrowly spatulate tip with blunt dorsal expansion (Fig. 24D); ostial canal extended from ostium along dorsal margin of lobe’s right side, terminated ventrad blunt dorsal expansion; flagellar plate relatively short, length 0.4× distance from parameral articulations to apical face; right paramere narrowed apically.

Female gonocoxae. The female allotype was not dissected, but examining the distended abdomen (Fig. 22E) allows the following observations: basal gonocoxite 1 broad (dimensions similar to those in Fig. 8E), with 2–3 apical fringe setae laterally and one apical seta near medioapical angle; 7–11 setae arrayed from apex to base of mesal half of gonocoxite ventral surface; apical gonocoxite 2 narrow basally, subtriangular, with two lateral ensiform seta, the basal seta longer and narrower at base, and one dorsal ensiform seta; apical sensory furrow with two apical nematiform setae.

Holotype male (MNHN) labeled: FRENCH POLYNESIA: Tahiti Iti / Mont Atara, 815 m el. / 17°47.4425'S, 149°14.8103'W / 20-ix-2012, T. Ramage, Winkler / extraction of mossmat siftate // PF 1135 // HOLOTYPE / Mecyclothorax / ramagei / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled as holotype // ALLOTYPE / Mecyclothorax / ramagei / J.K. Liebherr 2013 (black-bordered red label).

The species epithet is a patronym honoring the collector, Thibault Ramage, entomological consultant, Concarneau, France.

This species is distributed on the Tahiti Iti volcano. The type series was obtained by sifting mossmats on tree trunks, and extracting the insects from the siftate using a Winkler extractor (T. Ramage pers. comm.).

Among the larger-bodied species of the Mecyclothorax dannieae group – standardized body length 5.4–5.6 mm – characterized by a transverse pronotum (Figs 23A, B), this species is characterized by the presence of only one apical elytral seta; setal formula 2221. The seta is present apicad the juncture of striae 3 + 4, and as detailed in the Setation section above, represents the apical seta of the plesiomorphic apical plus subapical elytral setal pair, its position evolutionarily transformed to a more basal position. The head is covered with evident microsculpture, the sculpticells transversely stretched and in transverse rows on the frons, more isodiametric on the neck. The pronotal disc and discal elytral intervals bear well-developed transverse mesh microsculpture, with sculpticell breadth 2–3× length. The male aedeagal median lobe (Fig. 24E) is apically expanded, much like that observed in Mecyclothorax brittoni (Figs 24C), but the apical portion is longer, and the tip flares out ventrally to complement the more broadly rounded dorsal expansion. The male right paramere is apically lamellate, the ventral surface lined with setae (Fig. 24E). The internal sac bears a dorsal ostial microtrichial patch.

This species was previously known from two male specimens Perrault (1986) collected in 1976 at 1750 m elevation on Mont Aorai. A third specimen, also a male, was collected from leaf litter, 17–20 June 1949 at 2042 m elevation on Aorai (FMNH); i.e., 24 m in elevation below the summit.

Among species of the Mecyclothorax dannieae group with well-impressed elytral striae and setal formula 2221 (Figs 23, 25B–D), this species can be diagnosed by the pronotum with explanate lateral margins outside the laterobasal depressions, and the convexly curved basal pronotal margin immediately mesad the basal pronotal seta (Fig. 23C). The elytra are narrowed basally, MEW/HuW = 2.10–2.19 (n = 5), and the humeri are narrowly rounded, with the lateral marginal depression bordered along the elytral margin by an upturned edge. If a male specimen is available, the dramatically expanded aedeagal median lobe apex with acuminate dorsal process (Fig. 24F), will easily diagnose this species. Standardized body length 5.3–5.8 mm. Head with shallow frontal grooves, laterally margined behind by a rounded carina mesad anterior supraorbital seta, fine wrinkles radiating onto frons, groove broad and smooth anteriorly near frontoclypeal suture; eyes moderately protruded, ocular ratio 1.39–1.49, ocular lobe extended from gena at >135° angle, lobe margined behind by broad, shallow groove at gena, ocular lobe ratio 0.75–0.83; antennae elongate, filiform, antennomere 8 length 2.25× maximal breadth. Pronotum moderately transverse, MPW/PL = 1.23–1.33; median base moderately depressed relative to convex disc, about 16 punctures each side and 5-8 elongate punctures along margin with disc; anterior transverse impression broad, shallow but traceable across breadth, about 6 densely arrayed longitudinal strigae crossing impression each side near midline; frontal angles broadly rounded, protruded, lateral marginal depression broader inside angle, narrower behind with margin most beadlike near lateral pronotal seta, margin progressively broader basally, the sinuous laterobasal depression lined with rounded depressions. Elytra obovate, the humeri narrowed basally, greatest width just posterad midlength; elytral striae 1–6 deep, irregular along length, the irregularities taking the form of crenulations in the strial walls, discal intervals broadly, moderately convex, stria 7 slightly shallower but still irregular along length; eighth interval more convex medially and laterally at elytral apex, bulging ventrally, not upraised dorsally along seventh stria; lateral elytral setae 7 + 6. Metathoracic wings thickened, stenopterous, apex extended beyond hind margin of metanotum, length 2.5× breadth, apex narrowly rounded; remnants of Sc+R and M veins present. Microsculpture of pronotum well developed, disc covered with transverse mesh, anterior callosity, lateral marginal depressions, and median base between punctures lined with upraised isodiametric mesh; discal elytral intervals covered with well-developed transverse mesh, sculpticell breadth 2–3× length. Coloration of head dark rufous; antennomeres 1–11 rufoflavous, 4–11 with smoky cast; pronotal disc dark rufous with silvery metallic reflection; elytral disc rufobrunneous with a purplish metallic reflection; femora rufoflavous with brunneous cast, tibiae rufobrunneous.

Male genitalia. Aedeagal median lobe shaft slightly broader at midlength, ventral surface slightly convex (Fig. 24F); apex broadly curved dorsally beyond ostium, the apex expanded both dorsally and ventrally, the ventral expansion angulate at the very broadly curved apical face, the dorsal surface acuminate; ostial canal situated on left face of apex, very near and parallel to the dorsal margin; right paramere expanded apically as a ventrally setose lamellate structure; internal sac narrowly tubular, with broadly distributed ventral ostial microtrichial patch, and smaller dorsal ostial microtrichial patch; flagellar plate short, length 0.30× distance from parameral articulations to apical face.

Female reproductive tract. Bursa copulatrix broad with rounded apex, length 2.5× length, cuticle appearing thick based on depth of staining with Chlorazol Black (Fig. 14C); basal gonocoxite 1 quite setose (Fig. 8E), 4–5 setae near apex at medial angle, 4–5 setae along lateral margin of coxite, and unilaterally one seta isolated between; medial surface of gonocoxite 1 lined with about 13 smaller setae; apical gonocoxite 2 robust, broad basolaterally with broadly rounded apex, bearing two broad, parallel-sided lateral ensiform setae and one tapered dorsal ensiform seta; apical sensory furrow bearing two apical nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / pitohitiensis / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN): same data as holotype.

Paratypes: Tahiti Nui; Pito Hiti, 2070 m el., 17°36.819'S, 149°27.842'W, 2-vi-2006 lot 01, Claridge, pyrethrin fog (CUIC, 2; EMEC, 3; NMNH, 1); same data as holotype (CUIC, 2; EMEC, 4); 2080 m el., 17°36.806'S, 149°27.842'W, 2-vi-2006 lot 03, Claridge, pyrethrin fog (EMEC, 1).

This species name is derived from the type locality, Piti Hiti, resulting in an adjectival epithet – pitohitiensis – that is derived in parallel with that of the closely related species, Mecyclothorax tahitiensis.

All specimens representing this species have been collected from 2000–2080 m elevation on Pito Hiti via pyrethrin fogging of moss-covered vegetation.

This species is easily diagnosed by the broadly ellipsoid elytra and small, little transverse pronotum, MPW/PL = 1.25 (n = 2) (Fig. 23D). It shares pronotal proportions with the sympatric Mecyclothorax ramagei (Fig. 22E), but differs in the larger body size, standardized body length 5.3–5.6 mm, and by the presence of two supraorbital setae each side; setal formula 2221. Mecyclothorax teatara is characterized by elytral intervals covered by dense transverse lines, with only occasional cross-connections resulting in transverse sculpticells versus the transverse mesh characterizing Mecyclothorax ramagei. The male aedeagal median lobe is nearly symmetrically expanded apically, with a rounded ventral and a subangulate dorsal expansion, and the apex face is rounded (Fig. 24G). The ostial canal parallels the dorsal margin, and the right paramere is narrowly extended to a whiplike apex.

This species is known from 800–1100 m elevations on Mont Teatara, Tahiti Iti. One specimen was collected via pyrethrin fogging of mossy horizontal logs and mossy tree trunks.

Among species of the Mecyclothorax dannieae group, this species uniquely lacks dorsal elytral setae. The apical elytral setae are polymorphic in the single known specimen, with both apical and subapical setae on the right elytron, only the apical seta on the left; therefore the setal formula is 220(1–2). The discal elytral striae 1–5 are distinctly punctate in the basal half (Fig. 25A), the punctures elongate and expanding the strial breadth. The convexity of the eighth elytral interval equals that of the seventh, with a subcarinate ridge parallel to and near the seventh stria. The head bears evident microsculpture in depressed areas and wrinkles, with the isodiametric and transverse sculpticells on the frons arranged in a transverse mesh, the arrangement more isodiametric on the neck. The pronotal disc and discal elytral intervals have well-developed transverse microsculpture, a mixture of transverse lines and transverse mesh, the mesh comprising sculpticells with breadth 2–3× length. The male aedeagal median lobe is slender basally, and expanded both ventrally and dorsally at its apex (Fig. 27A), with the dorsal expansion more tightly rounded than the ventral. Standardized body length 4.3 mm.

The male holotype and only known specimen was collected between 900 and 1100 m elevation on Mont Marau.

This and the similarly sized Mecyclothorax teatara share the characteristics of a narrow, subquadrate pronotum and broadly ovate elytra (Figs 23D, 25B), but in Mecyclothorax tutei the pronotal hind angles are more angulate, the pronotal lateral margins less explanate, and the elytra base broader. The pronotal median base is also more punctate, with about 13 punctures each side of midline plus rugose wrinkles laterally, versus 6–8 small isolated punctures each and a smooth surface laterally in Mecyclothorax teatara. The head has a distinct isodiametric mesh in transverse rows covering the vertex. The pronotal disc is covered with a distinct transverse mesh, sculpticell breadth 2–4× length, and the discal elytral intervals bear a distinct transverse mesh, sculpticell breadth 2–3× length intermixed with transverse lines. Setal formula 2221; standardized body length 5.3 mm.

This species is known from 1080 m elevation on Mont Mauru, where the single known female specimen was collected by pyrethrin fogging tangles of dead fern fronds.

Among Mecyclothorax dannieae group species characterized by expanded lateral pronotal margins anterad the hind angles, and well-impressed, nearly smooth elytral striae (Figs 23A–C, 25A, C, D, and 26C, D), Mecyclothorax aorai stands out based on the subquadrate elytra with little convex discal elytral intervals (Fig. 25C). The apical elytral setae are polymorphic in this species, with either the apical seta alone present, or both apical and subapical setae present (this configuration varies unilaterally within individuals); setal formula 222(1–2). If a male is available, the diagnosis is certain, as the male aedeagal median lobe is exceedingly slender, with the apex extremely long and narrow and only slightly expanded at the tip (Figs 25C, 27B). The head bears well-developed microsculpture consisting of isodiametric sculpticells in transverse rows. The pronotal disc is covered with an elongate transverse mesh, sculpticell breadth 4× length, and the discal elytral intervals are lined with elongate transverse microsculpture consisting of transverse lines intermixed with transverse sculpticells, breadth 3–4× length. Standardized body length 5.2–5.9 mm.

This species is known to occur from 1200–1900 m elevation on Mont Aorai. All five known specimens were collected in association with moss-covered vegetation, either by finding specimens by hand in moss, or via application of pyrethrin insecticide fog to the vegetation.

This species is extremely similar to the preceding, Mecyclothorax aorai, and in addition to the characters of the key, can be diagnosed by the less transverse pronotum; MPW/PL = 1.20–1.27 (n = 2) for this species versus 1.30–1.37 (n = 2) for Mecyclothorax aorai. The pronotal basal margin is straighter immediately mesad the hind angles in this species (Fig. 25D), versus curved forward in Mecyclothorax aorai where the basal seta is placed noticeably anterad a line defined by the basal margin of the pronotum near the midline. Head with well-developed microsculpture consisting of upraised, transversely stretched sculpticells. The pronotal disc is covered with a swirling transverse mesh, the sculpticell breadth 3–4× length on lateral convex areas. Discal elytral intervals with rough-appearing transverse mesh microsculpture that includes a small proportion of isodiametric sculpticells, the sculpticell margins distinct, transverse sculpticell breadth 2–4× length. Setal formula 2221; standardized body length 5.7 mm.

This species is known to live on Mont Aorai from 1265 m to 1900 m elevation. One of the four known specimens was collected by beating live and dead fern fronds over a beating sheet, indicating the use of an arboreal refuge during daytime.

Of the five Mecyclothorax dannieae group species that exhibit setal formula 2222 (Figs 25C, 26), this species is characterized by a little transverse pronotum – MPW/PL = 1.18–1.26 (n = 5) – with basal margins anteriorly rounded just behind the basal pronotal setae (Fig. 26A). The subquadrate elytra are broad relative to the small pronotum; MEW/MPW = 1.55–1.62. The male aedeagus is perhaps the most distinctive among Tahitian Mecyclothorax (Fig. 27C), with a broadly expanded right side to the median lobe laterad the ostium, and a sharply downturned apex. The ostial canal runs along the dorsal surface of the median lobe indicating that the right face of the lobe has been distortedly expanded to produce this configuration. The internal sac bears a stout spicule. The head is glossy in part, with transverse mesh microsculpture in the frontal grooves and associated wrinkles, and an isodiametric mesh on the neck. The pronotal disc is covered with an evident transverse mesh, sculpticell breadth 2–4× length. The discal elytral intervals are lined with transverse lines, only occasionally joined into a mesh with elongate transverse sculpticells. Standardized body length 5.5–5.9 mm.

This species is known from Mont Marau at 1000–1400 m elevations. Associated ecological data are restricted to arboreal situations; in banks of living Dicranopteris ferns, in dense banks of dead ferns, and on moss-covered trunks of Weinmannia trees with associated epiphytic Astelia plants.

Of the Mecyclothorax dannieae group species with setal formula 2222 (Figs 25C, 26), this species is characterized by the most well-defined pronotal hind angles, with the pronotal lateral margins slightly sinuate anterad the angles (Fig. 26B). The elytra are moderately narrowed basally, the subangulate humeri proximate. The male aedeagal median lobe is sinuously curved apically with a truncate apex (Fig. 27D), with the ostial canal starting at the right-directed apex of the ostium, and terminating near the dorsal margin of the median lobe apex. The male right paramere is expanded apically into a setose lamellate structure, as also observed in males of Mecyclothorax tahitiensis, Mecyclothorax pitohitiensis, and Mecyclothorax villiersi (Figs 24E, F, 27E). Of these four species, Mecyclothorax dannieae exhibits the most plesiomorphic median lobe, with only slight sinuation of the lobe beyond the ostium, and minimal dorsoventral expansion at the tip. This species is characterized by well-developed microsculpture, including: 1, upraised, transversely stretched sculpticells covering the frons and vertex; 2, a swirling transverse mesh on the pronotal disc, sculpticell breadth 2–4× length; and 3, regular transverse mesh on the discal elytral intervals 1–4, sculpticell breadth 2–3× length, the mesh more elongate but just as regular on the lateral elytral intervals. Standardized body length 5.4–6.2 mm.

Perrault (1986) reported this species from 1000–2000 m on Mont Aorai. Several of his specimens from between 1100 and 1400 m elevation were collected in vinegar pitfall traps.

This member of the Mecyclothorax dannieae species group quartet with setal formula 2222 can be diagnosed by the transvere pronotum with trisinuate basal margin, the margin convexly curved behind the pronotal laterobasal depression toward the obtuse-rounded hind angle defined by the articulatory socket of the basal pronotal seta (Fig. 26C). The rufoflavous femora and tibiae contrast with the rufobrunneous to rufopiceous dorsal body color. The male aedeagal median lobe is sinuously curved apically, with the apex expanded both dorsally and moreso ventrally (Figs 3E, 27E). The ostial canal runs along the dorsal margin of the apex. The right paramere is expanded apically as a setose lamellate structure. The internal sac is tubular, with a variously developed dorsal ostial microtrichial patch, broad ventral ostial microtrichial patch and a small flagellar plate, the plate length 0.22× the distance from the parameral articulations to the apical face (Fig. 27E). The head bears shallow to evident microsculpture consisting of isodiametric and transverse sculpticells in transverse rows. The pronotal disc is covered with distinct transverse mesh microsculpture, the sculpticells isodiametric to 3× broad as long, and the discal elytral intervals are lined with upraised transverse sculpticells, the surface rough on the inner four intervals. Standardized body length 5.0–6.0 mm.

This species is known from Mont Marau at elevations between 1000 and 1400 m. All individuals with ecological data have been associated with arboreal microhabitats on a variety of plant substrates: Melicope, Myrsine, and Weinmannia, as well as ferns. Specimens have been obtained by beating such vegetation, and through the use of pyrethrin insecticide fog on moss-covered vegetation and dense fern banks.

Among the Mecyclothorax dannieae group species with setal formula 2222, this species can be diagnosed by a pronotum with distinct, obtuse hind angles and straight lateral margins anterad the angles (Fig. 26D). The basal pronotal setae are situated directly inside the obtuse angles on an expanded portion of the upraised margin. The pronotal basal margin is indistinctly trisinuate, with slight concavities posterad the deepest portions of each laterobasal depression. The elytra are broad basally, with rounded humeri. The male aedeagal median lobe is even curved with a dorsoventrally expanded apex with a straight apical face (Fig. 27F). The right paramere has an expanded apex with subparallel margins; a configuration observed in males of Mecyclothorax brittoni (Fig. 24C). The head is uniformly covered with distinct isodiametric and slightly transverse sculpticells in transverse rows. The pronotal disc is covered with a transverse mesh, sculpticell breadth 1–3× breadth, and the discal elytral intervals are lined with an elongate transverse mesh, sculpticell breadth 3–4× length. Over portions of the elytra, the cross-connections of the mesh are reduced producing transverse-line microsculpture. Standardized body length 5.6–6.4 mm.

The four known specimens of Mecyclothorax negrei have been collected on Mont Aorai from 1000 to 1900 m elevation.

Among members of this group, this species is diagnosable by the very glossy upper body surface, with the vertex, pronotal disc, and discal elytral intervals extremely smooth such that tiny micropunctures – pore canals – are visible across the smooth surface. The pronotal hind angles are obtuse and only slightly protruded, the projection consisting of an expansion of the marginal bead surrounding the articulatory socket of the basal pronotal seta (Fig. 28A). The pronotal median base is distinctly punctate with about 20 rounded punctures each side that are isolated by glossy cuticle. All elytral striae are deep with rounded punctures that expand their breadth in the basal half. The eighth elytral interval is subcarinate immediately laterad the seventh stria and convex laterally. There are two to three setae near the elytral apex; a short one in interval 7 along the elytral margin, and a second longer one laterad the apically fused terminus of striae 3 + 4. In the male paratype examined (MNHN), there is a third short seta immediately basal to the second; setal formula 222(2-3). The male aedeagal median lobe is narrowed apically, with a small rounded expansion of the tip (Fig. 3A). The right paramere is parallel sided, and slightly expanded to its tightly rounded apex. Standardized body length 5.9 mm.

This species is known from the type series of five specimens collected at 1000 m elevation on Mont Marau.

Beetles of this species appear much like those Mecyclothorax striatopunctatus, with basally broad elytra bearing distinctly punctate striae and convex intervals, and glossy dorsal body surface (Figs 28A, B). However this species exhibits rudimentary transverse microsculpture on the head and pronotum, and distinct transverse mesh microsculpture, sculpticell breadth 2–3× length, on the discal elytral intervals. The pronotal median base is distinctly punctate, with >25 deep, round punctures each side, and the pronotal hind angles are more rounded than in Mecyclothorax striatopunctatus. In Mecyclothorax wallisi, the basal pronotal seta is positioned anterad the rounded hind angles, and its articulatory socket causes a jag in the basal portion of the pronotal lateral margin. The eighth elytral interval is broadly convex laterad the seventh stria, with its surface bulging laterally. The male aedeagal median lobe is similar to that of male Mecyclothorax striatopunctatus (Fig. 3A), with an evenly curved gracile shaft that is elongate apicad the ostium, and a dorsoventrally expanded apex, the ventral expansion larger and more rounded (Perrault 1986: fig. 22) than observed in the males of Mecyclothorax striatopunctatus (Fig. 3A). Setal formula 2222; standardized body length 5.9–6.2 mm.

Perrault (1986) collected the type series between 1000 and 1800 m elevation on Mont Aorai. One subsequent specimen was collected by beating dead and live fern fronds between 1265 and 1320 m elevation on Aorai.

Unique among the Mecyclothorax striatopunctatus group in the orbicular pronotum with broad pale margins, and the obovate elytra with pale, broadly explanate lateral marginal depressions (Fig. 28C). Setal formula 2221; standardized body length 5.4 mm. Head with deep frontal grooves, narrow behind and depressed mesad a low carina inside anterior supraorbital seta, sinuous toward midline at midlength, and broad, shallow near frontoclypeal suture; eyes moderately convex but small in diameter, ocular ratio 1.50, ocular lobe distinctly expanded from gena, ocular lobe ratio 0.80; antennae moderately elongate, filiform, eighth anennomere length 2.0× maximal breadth. Pronotum transverse, MPW/PL = 1.31, orbicular, with broadly rounded hind angles and convex basal margin; basal pronotal setae expanding lateral margin, causing minute jag in margin, the seta and jag set 0.12× pronotal length anterad the pronotal basal margin at the midline; median base with four shallow, isolated punctures each side and 7–8 longitudinal wrinkles at juncture with disc; anterior transverse impression broad, shallow, complete medially, crossed by 10–11 fine wrinkles in median quarter of each side; front angles broadly rounded, little protruded anteriorly, the lateral marginal depression gradually widened posterad to base, laterobasal depression defined by a U-shaped depression that is continuous with the lateral depression surrounding a low, irregular tubercle. Elytra narrow basally, MEW/HuW = 2.67, the basal groove distinctly recurved anteriorly to the subangulate humerus; parascutellar seta on papillate dome that is bordered behind by a depression connecting parascutellar striole and interval 1; disc depressed across first four intervals each side directly posterad the inflated parascutellar striole; flat lateral marginal depression gradually widened with margin more upraised posterad humerus, achieving maximal breadth near posterior seta of anterior lateral elytral setal series; discal elytral striae 1–6 deep, set with distinct elongate punctures that expand the strial breadth in a crenulate pattern; stria 7 shallow, finely inscribed, punctures isolated, especially apically; eighth elytral interval upraised above striae 7 from anterad subapical sinuation to apex, tightly convex, looking pinched laterally dorsad subapical sinuation; lateral elytral setae 7 + 1 + 5 (left) and 7 + 6 (right) of unique holotype. Metathoracic wings stenopterous straps 4× long as wide, margins parallel in apical half, apex narrowly rounded; alae with distinct Sc+R and M veins present, and indistinct wrinkles in cubital region of wing rudiment. Microsculpture of head a distinct transverse mesh visible across frontal grooves, frons, and vertex; pronotal disc covered with well-developed transverse mesh, the sculpticell pattern influenced by wrinkles radiating from the disc center, sculpticell breadth 3–4× length; discal elytral intervals with regular transverse mesh, sculpticell breadth 2–3× length, with some isodiametric sculpticells intermixed. Coloration of head a uniform rufobrunneous; antennomere 1 flavous, each antennomere 2-11 rufobrunneous basally, rufoflavous apically; pronotal disc rufobrunneous to match head color, lateral marginal depression rufoflavous, palest at front angle; elytral disc flavobrunneous, paler than head and pronotal disc; elytral lateral marginal depression concolorous with disc at humerus, paler apically all the way to subapical sinuation; femora brunneous with flavous apex, tibiae flavous with brunneous cast. Male abdomen with extra transverse, arcuate fold near midlength of visible abdominal ventrite 6, resulting in a partially formed ventrite 7; two smaller setae at apical margin of pseudosegment 6, in line with accessory setae of ventrites 3–5; apical margin of pseudosegment 7 with the usual two apical setae at lateral quarter of breadth each side.

Male genitalia. Aedeagal median lobe only moderately curved, ventral surface of shaft straight apicad parameral articulations (Fig. 27G); median lobe apex short, rounded, slightly more expanded on dorsal margin; ostial canal starting on ride side of lobe apex, terminated closer to dorsal margin; flagellar plate elongate, length ~0.50× distance from parameral articulations to apical face; right paramere slightly broadened, parallel sided from base to tightly rounded apex.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Iti / Mts. Teatara summit / 1195 m el. 17-IX-2006 lot 10 / 17°47.907'S, 149°14.183'W / pyr. fog Astelia on mossy / log C.P. Ewing // HOLOTYPE / Mecyclothorax / curtisi / J.K. Liebherr 2013 (black-bordered red label).

The patronymic species epithet curtisi honors the collector, Dr. Curtis P. Ewing, who collected extensively at the summit of Mont Teatara, one of several inaccessible French Polynesian peaks he has worked hard to explore.

The holotype and only known specimen was collected at 1195 m elevation at the summit of Mont Teatara, Tahiti Iti. The specimen came from a pyrethrin fog sample of a horizontal mossy log with an epiphytic Astelia plant growing on it.

This species shares with Mecyclothorax curtisi the rounded pronotal hind angles and basal pronotal setal placement 0.12× the pronotal length before the median basal margin, but differs in: 1, the nearly concolorous pronotal and elytra discs and margin; 2, the very convexly domed elytra with the scutellum much depressed from the middle of the disc; 3, the presence of both apical and subapical elytral setae, therefore a setal formula of 2222; and 4, larger size, standardized body length 6.2 mm. Like Mecyclothorax curtisi, the pronotal median base has only small, shallow punctures, about 8–10 each side, and elongate wrinkles along the juncture with the disc. The head is glossy with an indistinct transverse mesh visible in wrinkles and on the neck. The pronotal disc is also glossy, with elongate transverse mesh microsculpture visible in the lateral marginal depressions and laterobasal depressions, as well as the median base between punctures. The discal elytral intervals are covered with a shallow, regular transverse mesh, sculpticell breadth 2–3× length. The male aedeagal median lobe is slightly more curved than in Mecyclothorax curtisi, but shares: 1, a short apex (Fig. 3B); 2, an ostial canal that traverses the right face and terminates near the dorsal margin; and 3, a right paramere that is somewhat broad and parallel sided from base to tightly rounded apex. The apex of the median lobe in Mecyclothorax bougainvillei males uniquely bears an apical tooth that extends from the basal quarter of the apical face.

All that is known about this species’ distribution is the elevation of the type locality for the unique holotype: 1400 m elevation on Mont Marau.

This is the smallest-bodied species in the Mecyclothorax striatopunctatus group, standardized body length 5.3 mm, and it is further diagnosable by the little widened pronotal lateral depressions near the obtusely angulate hind angles (Fig. 29A). As in the preceding species, the basal pronotal setae are positioned anterad a transverse line defined by the median basal pronotal margin, but in this species the distance anterad is less, only 0.10× the pronotal length. The pronotal median base is mostly smooth, bearing 20–25 small, isolated punctures each side but no longitudinal wrinkles at the median base-pronotal disc juncture. The eighth elytral interval is elevated, broadly subcarinate above stria 7 dorsad the subapical sinuation, and convexly bulging laterally. The head bears a shallow, indistinct transverse mesh on frons and vertex, the surface only moderately glossy. The pronotal disc and median base are glossy, without indication of any sculpticells. The discal elytral striae are lined with elongate transverse microsculpture, consisting mostly of shallow transverse lines with occasional crossconnection causing areas of transverse mesh. Setal formula 2222.

The unique female holotype of this species was collected between 1000 and 1800 m elevation on Mont Aorai.

The pale rufoflavous head and pronotum, and pale-margined elytra with contrasting dark brunneous intervals 1–6 serve to diagnose this species at first glance (Fig. 29B). The presence of two supraorbital setae, lateral plus basal pronotal setae, and the absence of dorsal elytral setae – setal formula 2201 – serve to separate this species from all other Tahitian species with narrowly constricted pronota, with the single exception of Mecyclothorax kayballae sp. n. (Fig. 32A), a darkly metallic member of the Mecyclothorax viridis group. The frons and vertex of the head are covered with a regular, well-developed transverse mesh. The pronotal disc is similarly microsculptured, though the sculpticells are more elongate; 2–4× broad as long. The discal elytral intervals bear a regular transverse mesh, sculpticell breadth 2–4× length, with some isodiametric sculpticells in transverse rows mixed in. The male aedeagal median lobe is bowed dorsally, with the ventral margin straight apicad the parameral articulations, and the tip downturned to a rounded apex (Fig. 30A). The ostium extends almost to the tip, with the ostial canal short and parallel to the dorsal margin. Standardized body length 4.1–4.2 mm.

The known distribution of this species spans 1750–1900 m elevation on Mont Aorai.

This species can be diagnosed from Mecyclothorax marginatus by the narrower, more elongate pronotum – MPW/PL = 1.13–1.22 (n = 5) (Figs 29B, C) – and the more uniform coloration; rufobrunneous head and pronotum, and dark rufobrunneous elytra. On the elytra, only the moderately explanate elytral lateral marginal depressions are flavous. The male aedeagal median lobe is also diagnostic, with the apex broadly rounded as in males of Mecyclothorax marginatus, but not downturned (Figs 30A, B). Setal formula 2201; standardized body length 3.7–4.3 mm. Head with broadly convex frons, the frontal grooves posteriorly only a shallow, sinuous depression mesad fine carina inside eye, anteriorly a broad shallow triangular depression at frontoclypeal suture; eyes convex, ocular ratio 1.47–1.61, on ocular lobes that are distinctly protruded behind, ocular lobe ratio 0.84–0.87 (n = 5); antennae filiform, antennal segment 8 length 2.25× maximal breadth. Pronotum cordate, MPW/BPW = 1.50–1.60; lateral margins distinctly sinuate anterad distinct right to slightly obtuse hind angles, the lateral margins subparallel to convergent for short distance anterad angles; median base with 9–10 distinct, isolated punctures each side; median longitudinal impression moderately deep, crossed by 7–8 indistinct longitudinal wrinkles in median half of each side; lateral marginal depression narrowly upturned, the upturned area translucent, twice as broad and upraised basally laterad laterobasal depression; laterobasal depression a quadrate flat expanse inside hind angle. Elytra narrowly obovate, convex, sides sloped to nearly perpendicular with narrowly upturned lateral marginal depression; humeri proximate, angulate, a distinct hitch at the juncture of the basal groove and lateral marginal depression, MEW/HuW = 2.23–2.54; discal elytral striae shallow, with shallow punctures that expand the strial breadth but not depth, discal intervals only slightly convex; eighth interval broadly convex laterad stria 7 apicad subapical sinuation, not raised much above stria 7; lateral elytral setae 7 + 6. Microsculpture of head a distinct transverse mesh composed of isodiametric and transverse sculpticells; pronotal disc with evident transverse mesh, sculpticell breadth 2–3× length; discal elytral intervals covered with a distinct transverse mesh, sculpticells 2–3× length, mixed with areas of transverse lines. Coloration of head and pronotal disc rufobrunneous, pronotal margins narrowly rufoflavous; elytra rufobrunneous, the sutural interval rufous basally and rufoflavous apically, and the apex gradually more flavous apicad the subapical sinuation.

Male genitalia. Aedeagal median lobe bowed dorsally with straight ventral margin apicad parameral articulations (Fig. 30B), as in males of Mecyclothorax marginatus (Fig. 30A), but apex not downturned.

Female reproductive tract. Bursa copulatrix narrowly extended from broader vagina, the bursal extension twice as long as broad (Fig. 14D); basal gonocoxite 1 broad, squat, with apical fringe of four setae, three more laterally and a shorter one more medially (Fig. 8F), and 5–6 short setae in apical portion of median margin; apical gonocoxite 2 broadly extended laterally, with arcuate lateral margin and narrow, finely rounded apex; apical gonocoxite with two narrow lateral ensiform setae and one narrow dorsal ensiform seta; apical sensory furrow with two nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / hoeahiti / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled as holotype.

Paratypes: labeled as holotype (EMEC, 1); Tahiti Nui, Pito Hiti, 2070 m el., 17°36.813'S, 149°27.842'W, 2-vi-2006 lot 01, Claridge, pyrethrin fog (EMEC, 1), 2080 m el., 17°36.806'S, 149°27.842'W, 2-vi-2006 lot 03, Claridge, pyrethrin fog (CUIC, 2; EMEC, 1).

The species epithet compounds the Tahitian word for same, hō’ēā with the word for edge, hiti, signifying the similar coloration of pronotal and elytral margins in beetles of this species; Mecyclothorax hoeahiti.

This species is known from pyrethrin fogging of moss-covered vegetation from 2000–2080 m elevation on Pito Hiti.

Among the five species in the Mecyclothorax viridis group that exhibit smaller body size, standardized body lengths 3.3–4.2 mm (Fig. 31), this species is characterized by a very dark, glossy dorsal surface with metallic blue reflection. The head, pronotal disc, and discal elytral intervals lack distinct microsculpture, with areas of obsolete, elongate transverse mesh visible over portions of each somite. Only the first and seventh elytral striae are deeply impressed apically, with the second stria broader and much less defined. Setal formula 2221; standardized body length 3.5–4.0 mm. Head with narrowly incised, subparallel frontal grooves, the mesal surface with transversely radiating wrinkles inside anterior supraorbital seta, grooves broader, quadrately depressed at frontoclypeal suture; eyes moderately convex but with dorsal margin convexly convergent, ocular ratio 1.49–1.55, ocular lobe distinctly protruded from gena, ocular lobe ratio 0.82–0.89; antennae short, submoniliform, antennomere 8 length 1.75× maximal breadth. Pronotum cordate, lateral margins distinctly convergent anterad right to slightly obtuse, protruded hind angles, MPW/BPW = 1.49–1.56 (n = 5), and moderately transverse, MPW/PL = 1.19–1.24; median base only slightly depressed relative to disc, 16–19 deep, rounded punctures each side, the punctures more elongate along juncture with disc; anterior transverse impression broad, shallow, medially crossed by indistinct longitudinal wrinkles in some individuals, defined anteriorly by upraised, nearly flat anterior callosity; front angles not protruded, rounded behind; lateral marginal depression narrow throughout length, edge beaded, broadened inside front angle; laterobasal depression a narrow oblique continuation of lateral marginal depression, surface punctate, the depression defining a triangular raised area with the basal pronotal seta. Elytra broadly ovate, convex, sides distinctly sloped to vertical at lateral marginal depression; humerus broadly angulate laterad the evenly curved basal groove; striae 1–7 shallow but evident, continuous, obsolete basally and not reaching basal groove, indistinctly punctate in basal half, smooth and deeper apically; lateral marginal depression broadest at humerus, narrow with beaded margin posteriorly; interval 8 more convex than intervals 2 or 7 at elytral apex, surface broadly convex both dorsally and laterally; lateral elytral setae 7 + 6; the lone apical elytral seta in outer half of terminally fused striae 3 + 7 near apical terminus of interval 8. Coloration of head rufopiceous with silvery reflection, mandibles rufoflavous; antennomeres 1–3 rufoflavous, 4–11 with rufous cast; pronotal disc rufopiceous with indistinct blue-green reflection, only the median base paler, rufobrunneous near margin; elytral disc rufopiceous with more distinct blue-green reflection, lateral marginal depression narrowly rufobrunneous at humerus, rufoflavous apically; femora and tibiae contrastedly pale, rufoflavous, the tibiae with brunneous cast.

Male genitalia. Aedeagal median lobe curved dorsally, apex broadened dorsoventrally with broad, flat apical face (Fig. 30C), the apical configuration an exaggeration of that observed in males of Mecyclothorax viridis (Fig. 30D); flagellar plate relatively elongate for the short median lobe, length 0.52× distance from parameral articulations to apical face.

Female reproductive tract. Bursa copulatrix elongate, symmetrical and only slightly narrower than vagina in unstretched configuration (Fig. 33A), bursal + vaginal length 3.7× bursal breadth when flattened under cover slip; basal gonocoxite 1 short, broad, with apical fringe of four setae and 6–8 smaller setae along medial margin (Fig. 9A); apical gonocoxite 2 stout, moderately expanded basally with arcuate lateral margin, and bearing two subequal lateral ensiform setae, a dorsal ensiform seta; apical sensory furrow with two apical nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / ninamu / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2070 m 2-VI- / 2006 lot 01 pyrethrin fog / 17°36.813'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / ninamu / J.K. Liebherr 2013 (black-bordered red label).

Paratypes: 3 paratypes labeled as the holotype (CUIC, 2; EMEC, 1).

The Tahitian word nīnamu means blue as in the blue color of a lagoon, and signifies the metallic dorsal coloration of these beetles.

This species inhabits the summit area of Pito Hiti from 2000–2070 m elevation, with specimens collected from moss-covered vegetation through the application of pyrethrin fog.

Within the Mecyclothorax viridis group this species shares with Mecyclothorax ninamu the absence of discernible microsculpture on the dorsal body surface and cordate pronotum (Figs 31A, B), but the dorsal body coloration is not so dark, with the head a dark rufobrunneous, contrasted with the metallic piceous elytral disc. The overall body is narrower, with the pronotum less transverse, MPW/PL = 1.11–1.15 (n = 2), and the elytra more narrowly ovate. The elytral striae are more well developed in this species, with the eighth interval subcarinately elevated above striae 7 apicad the subapical sinuation, and striae 2–4 nearly as deep as the sutural stria 1 on the elytral apex. The male aedeagal median lobe is similar to that observed in males of Mecyclothorax nimanu (Figs 30C, D), but the apical expansion is more narrowly rounded, and the apical face more convex. Setal formula 2221; standardized body length 3.4–3.9 mm.

This species is known only from near the summit of Mont Aorai, with all specimens collected between 1750 and 1900 m elevation.

This smallest-bodied Tahitian Mecyclothorax – standardized body length 3.35 mm – is also diagnosable by the broadly flavous pronotal and elytral margins contrasted with rufopiceous discs, and small, little convex eyes (Fig. 31C); ocular ratio 1.41 (n = 2), ocular lobe ratio 0.75–0.76. The antennae are very short, the segments moniliform, with the antennomere 8 length 1.5× its maximal breadth. Setal formula 2221. Head with broadly impressed frontal grooves, sinuously curved toward midline anteriorly, frons broadly convex between groove and antennal base; eye diameter anteriorly defined by antennal articulation crossing 12 ommatidia. Pronotum moderately transverse with broad base, MPW/PL = 1.22–1.24, MPW/BPW = 1.45; lateral margin straight anterad obtuse hind angle that is defined by triangular, raised expansion of lateral bead that houses basal pronotal seta articulatory socket, the hind angle therefore little more than a jag in the pronotal margin at the basal seta; median base slightly depressed relative to disc, rugosely wrinkled laterally, ~5 elongate punctures each side along margin with disc; anterior transverse impression shallow, broad, crossed by 3–4 very fine, indistinct wrinkles each side of midline; front angles rounded, not protruded, lateral marginal depression very narrow even at front angles, the edge beaded; laterobasal depression a broad expansion of lateral margin depression, crossed by transverse raised areas that also occur near base of lateral depression. Elytra subquadrate, slightly convex medially, flattened behind scutellum; striae 1–7 distinctly impressed, with elongate punctures in basal half, striae 1 + 2, 3, 4, and 5 continuous to basal groove; interval 8 broadly convex laterad stria 7 at elytral apex, only slightly raised above level of interval 7; lateral elytral setae 7 + 6. Metathoracic wings assessable due to breakage of left elytron from paratype; wing rudiment triangular with anterior subcostal margin 1.5× length of truncate apical margin, the wing apex extended only to posterior margin of metanotum; alar surface ridged, with unmelanized indications of Sc + R and M veins, and a transverse budge more apically that seems not homologous with a vein as it does not reach the alar base. Microsculpture of frons a transverse mesh, sculpticell breadth 2–4× length, with more transverse sculpticells in frontal grooves, sculpticells isodiametric on neck; pronotal disc with shallow transverse mesh, breadth 2–4× length intermixed with transverse lines; elytral disc with well-developed transverse mesh, breadth 2–4× length. Coloration of head rufous, more flavous behind eyes and near dark rufous frontoclypeal suture; antennomeres 1–3 flavous, 4–11 rufoflavous; pronotal disc each side of midline rufobrunneous with silvery reflection, lateral margins broadly flavous, anterior callosity and median base rufoflavous; elytral disc rufopiceous with purplish metallic reflection; base and humerus, lateral depression and ninth interval, apex of eighth interval and elytral apex apicad apical seta all flavous; sutural interval broadly rufoflavous basally, paler apically; femora flavous, tibiae flavous with brunneous cast.

Female reproductive tract. Bursa copulatrix relatively elongate, vagina of similar diameter and therefore not discernible (Fig. 33B), bursal length >3.0× breadth compressed under cover slip; basal gonocoxite 1 narrow, with apical fringe of three setae placed laterally, and 6–8 setae lining the medial margin (Fig. 9B); apical gonocoxite 2 narrowly triangular, not extended laterally at base, rightly rounded apically, with two lateral ensiform setae, the basal seta of smaller diameter, and one dorsal ensiform seta; apical sensory furrow with two apical nematiform setae and two furrow pegs.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2000 m 2-VI- / 2006 lot 02 pyrethrin fog / 17°36.790'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / kokone / J.K. Liebherr 2013 (black-bordered red label).

Paratype: female specimen, reproductive tract dissected and left elytron removed (CUIC, 1).

The species epithet kokone is the Tahitian word for diminutive, and it signifies the very small body size of these beetles. Kokone is one of only a few Tahitian words (Wahlroos 2002) to share the k sound with Tahitian’s close linguistic relative, Hawaiian; a fitting connection given the derivation of Tahitian and Hawaiian Mecyclothorax biotas from the same Australian stock (Britton 1948; Liebherr 2012a).

This is another species known only from 2070 m elevation near the summit of Pito Hiti. As for the others, beetles of this species have been shown to inhabit arboreal moss on emergent vegetation through sampling using pyrethrin fog.

Among the smaller-bodied members of the Mecyclothorax viridis group with elytral striae 1–5 continuously impressed to the elytral basal groove (Fig. 31), this species can be diagnosed by the rufopiceous dorsal body coloration (Fig. 31D) and the well-developed microsculpture: 1, head covered with regular transverse mesh across frons, neck with isodiametric sculpticells; 2, pronotal disc with densely packed transverse microsculpture, consisting of elongate transverse sculpticells and unconnected transverse lines; and 3, elytral discal intervals bearing gratelike transverse microsculpture consisting predominantly of transverse lines, with some areas including crossconnections resulting in an elongate transverse mesh. Summarizing the type series of two specimens (Perrault 1986) plus six more specimens collected in 2006, only the 1986 female paratype unilaterally possesses a posterior dorsal elytral seta, the other elytron bearing only the anterior dorsal seta. Thus the most usual setal formula is 2211, a formula shared with Mecyclothorax paahonu, below. The male aedeagal median lobe is gracile and elongate, with an apicodorsal hooklike expansion (Fig. 30E). Standardized body length 3.8–4.1 mm.

In 1977, Perrault (1986) collected two specimens between 900 and 1100 m elevation on Mont Marau. In 2006 that elevational zone had become invaded with Albizia chinensis (Fabaceae) and was too dry for successful collecting. That year specimens were collected at 1275–1335 m elevation, through beating soft ferns and mossy Weinmannia branches, and via the use of pyrethrin fog on a tangled bank of dead ferns and a horizontal, moss-covered Weinmannia log.

Among the Mecyclothorax viridis group species, this is the only one to share the 2211 setal formula with Mecyclothorax castaneus, but differing from that species in coloration, with the elytral margins – lateral marginal depression and ninth interval – rufoflavously contrasted to each rufopiceous elytral disc. The rufopiceous disc of each elytron is isolated by the rufoflavous sutural interval (Fig. 31E). The elytral base is paler than the pronotal disc, rufobrunneous versus rufopiceous, and the lateral margins of the pronotum are subparallel for a greater distance anterad the right hind angles (Figs 31D versus E). Standardized body length 4.2 mm. Head with frontal grooves narrow posteriorly, linear, curved mesally inside broad convexity near frontoclypeal suture; eyes moderately convex, ocular ratio 1.48, ocular lobe hind margin quite obtuse to genal margin, ocular lobe ratio 0.75; antennae short, segments moniliform, antennomere 8 length 1.56× maximal breadth. Pronotum little transverse, MPW/PL = 1.17, base moderately broad, MPW/BPW = 1.47; median base slightly depressed relative to disc, rugosely wrinkled laterally, ~7 elongate punctures along margin with disc; anterior transverse impression broad, shallow, crossed by 8–10 finely inscribed, indistinct longitudinal wrinkles that extend across anterior callosity to anterior margin; front angles tightly rounded, very slightly protruded; lateral marginal depression very narrow, edge beaded, depression slightly wider inside front angles; laterobasal depression a broadened sinuate extension of lateral depression, crossed by transverse raised bars, basally defining a triangular raised area bearing basal seta articulatory socket. Elytra narrowly ovate, lateral margins rounded posterad from subangulate humeri; elytral striae 1–6 shallow, with fine irregular elongate punctures that little expand striae, stria 7 shallower, irregularly impressed along length but not punctate; striae 1+ 2, and 3–6 continuously impressed to elytral basal groove; interval 8 more broadly convex laterally near elytral apex than interval 7, but not upraised above stria 7 more than the inner interval; lateral elytral setae 7 + 6. Microsculpture of head a well-developed transverse mesh composed of transverse and isodiametric sculpticells in transverse rows, the sculpticells more isodiametric and upraised on neck; pronotal disc with shallow transverse mesh, sculpticells breadth 2–4× length; elytral discal intervals with regular transverse mesh, sculpticell breadth 2–4× length, with crossconnections absent from some limited areas resulting in transverse lines. Coloration of head uniformly rufobrunneous; antennomere 1 flavous, 2–3 rufoflavous, 4–11 rufobrunneous; pronotum rufopiceous with purplish reflection, lateral margins narrowly and median base broadly rufobrunneous; rufopiceous discs of each elytron with purplish reflection.

Holotype female (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2070 m 2-VI- / 2006 lot 01 pyrethrin fog / 17°36.813'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / paahonu / J.K. Liebherr 2013 (black-bordered red label).

The species epithet paahonu is taken from the Tahitian word for maroon, a rough approximation of the dorsal body coloration of the holotype.

Known from a pyrethrin fog sample of moss-covered vegetation taken 40 m elevation below the summit of Pito Hiti.

Of the Mecyclothorax viridis group species with evident transverse elytral microsculpture and basally obsolete elytral striae 1–5 (Fig. 32), this species uniquely lacks dorsal elytral setae; setal formula 2201. The dorsal coloration is dark, rufopiceous with a blue reflection (Fig. 32A), much darker than all other species in the group save Mecyclothorax ninamu (Fig. 31A), but beetles of that species are much smaller – 3.5–4.0 mm – versus those of Mecyclothorax kayballae; standardized body length 4.3–4.7 mm. Head with frontal grooves very shallow posteriorly, separated from anterior supraorbital seta by fine, low carina, frons mesally with radiating wrinkles, groove broadly, triangularly depressed anteriorly near frontoclypeal suture; eyes moderately convex, ocular ratio 1.49–1.50 (n = 3), ocular lobe protruded, posterior margin of lobe meeting gena at shallow groove with carina behind, ocular lobe ratio 0.80–0.83; antennae submoniliform, antennomere 8 length 1.80× maximal breadth. Pronotum cordate, base narrow, MPW/BPW = 1.61–1.63, moderately transverse, MPW/PL = 1.20–1.24; hind angles right to slightly obtuse, lateral margins convergent immediately anterad angle then distinctly divergent; median base convex medially, moderately depressed relative to convex disc, 12–14 distinct punctures each side plus 5–7 elongate wrinkles along margin with disc; anterior transverse impression finely incised laterally with fine wrinkles behind, obsolete near midline; front angles rounded, slightly protruded, lateral marginal depression narrow with beaded edge laterally, depression broader with less upraised margin at front angle; laterobasal depression a narrow, punctate expansion of lateral depression, defining laterally a triangular raised area bearing the basal seta articulatory socket. Elytra ovate, convex, scutellum depressed relative to disc, sides sloping to near vertical at lateral elytral depression; humeri proximate, but elytral margins extended laterally in a broad even curve posteriorly, MEW/HuW = 2.41–2.51; striae 1–6 shallow with distinct rounded punctures on disc, striae much shallower and impunctate near basal groove, appearing obsolete in dorsal view but traceable if basal surface of elytra is positioned horizontally in field of view; stria 7 very shallow with periodic shallow dimples along length; humeri angulate, elytral basal groove more distinctly curved laterally near juncture with lateral marginal depression; lateral marginal depression narrow throughout length, only slightly broader near midlength; elytral striae 2–7 reduced over much of elytral apex, the apex of stria 7 impressed apicad subapical sinuation, with interval 8 more convex at that point resulting in a short, subcarinate ridge adjacent to stria 7; elytral lateral setae 7 + 6. Microsculpture of frons transverse, obsolete, the surface glossy between areas with visible sculpticells, neck with more visible transverse microsculpture, the rows including isodiametric and transverse sculpticells; pronotal disc with regular, shallow transverse mesh, sculpticell breadth 2–3× length; discal elytral intervals covered with a mixture of transverse sculpticells, sculpticell breadth 3× length, and transverse lines. Coloration of frons and vertex rufopiceous, clypeus and labrum rufobrunneous; antennomeres 1–4 rufoflavous, 5–11 with brunneous cast; pronotal disc rufopiceous, lateral marginal depressions narrowly rufobrunneous, median base dark rufous; elytral disc rufopiceous in basal half, rufous in apical half, sutural interval paler, rufobrunnous only near apex; lateral marginal depression narrowly rufobrunneous; femora and tibiae contrasted with body coloration, rufoflavous.

Male genitalia. Aedeagal median lobe distinctly dorsally curved, apex very short, the tip subacuminate (Fig. 30F).

Female reproductive tract. Bursa copulatrix and vagina separated by a distinct constriction (Fig. 6A), length of bursa plus vagina slightly more than twice bursal breadth compressed under cover slip; basal gonocoxite 1 elongate, with apical fringe of four setae, three larger setae laterally and one smaller, isolated seta medially, 5–6 setae along mesal margin and several more on ventral face (Fig. 9C); apical gonocoxite 2 broadly extended laterally at base, apex subacuminate, lateral margin broadly arcuate, with two lateral ensiform setae, the apical seta broadened along shaft, one dorsal ensiform seta; apical sensory furrow with two apical nematiform setae and two furrow pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Marau road el. 1125 m / 4-IX-2006 lot 01 / 17°36.437'S, 149°33.110'W / beat dead tree fern fronds / wet rock face J.K. Liebherr // 1 // HOLOTYPE / Mecyclothorax / kayballae / J.K. Liebherr 2013 (black-bordered red label).

Paratypes: same data as holotype (CUIC, 2). The paratypes have been dissected for male genitalic and female reproductive tract description.

This species is named in honor of Dr. Kathleen Ball for her support for and active engagement in the carabidological community. It should be noted that Mecyclothorax kayballae and Mecyclothorax balli, named by Georges Perrault in honor of Professor George Ball, co-inhabit Mont Marau, establishing the possibility of collecting both species during a one day’s trip to the summit.

This species is known from the type series collected at 1125 m elevation on Mont Marau. The beetles were beaten from dead fern fronds that were associated with living plants growing on a wet rock face.

Among the Mecyclothorax viridis group species with basally reduced elytral striae and two dorsal elytral setae (Figs 32B–E), diagnosable by the very transverse elytral microsculpture composed of transverse lines with little development of a mesh, and larger standardized body length, 4.8–5.1 mm. From the smaller bodied Mecyclothorax putaputa, with which this species shares the very transverse elytral microsculpture, this species can be differentiated by the deep, distinctly punctate discal elytral striae and associated convex intervals (Figs 32B), and the distinctly sinuate lateral pronotal margins and projected pronotal hind angles. The vertex of the head is glossy with the shallow to obsolete transverse microsculpture partially to totally obscured by irregular transverse wrinkles. The pronotal disc is covered with an obsolete (male paratype) to shallow (female paratype) elongate transverse mesh mixed with transverse lines, the defined sculpticells 2–4× broad as long. The male aedeagal median lobe has an elongate, parallel-sided apex with oblique apical face (Fig. 30G); the elongate apex a shortened version of the exaggeratedly elongate apex observed in males of Mecyclothorax ata (Fig. 30H). Setal formula 2221.

All that is known about the biology and distribution of this species is restricted to the 1976 collection of the eight-member type series from 1300–1400 m elevation on Mont Marau (Perrault 1978b).

This species shares with Mecyclothorax balli the setal formula 2221, effaced elytral striae near the elytral basal groove, and transverse-line elytral microsculpture, but these beetles are smaller, standardized body length 4.3–4.5 mm versus 4.8–5.1 mm for Mecyclothorax balli. The pronotal hind angles are marked by a large transverse fault-like hitch in the pronotal margin, with the margin before and after the hitch of nearly the same curvature (Fig. 32C). The elytral striae are moderately shallow with elongate punctures that impress the stria in a dashed pattern. The head bears distinct transverse mesh microsculpture mixed with transverse lines, the defined sculpticells only slightly broader than long, and the pronotal disc is covered with a shallow but evident transverse mesh, sculpticell breadth 2–3× length.

This species is so far known to be associated with low-stature Metrosideros and Weinmannia forest from 1065–1100 m elevation on Mont Mauru. The two specimens were in subarboreal microhabitats from which they were beaten onto a sheet or collected through the use of pyrethrin fog.

Among the Mecyclothorax viridis group, this species comprises narrow-bodied beetles with subquadrate elytra and a cordate pronotum, the pronotal hind angles right and the basal margins preceding them angularly convergent (Fig. 32D). The elytral striae are deep though finely inscribed, with rounded punctures that expand the strial breadth. As opposed to the preceding two species (Figs 32B, C), this species is characterized by a very well-developed transverse mesh on the discal elytral intervals, the sculpticells raised and varying from isodiametric to transverse with breadth 2× length. The frons is glossy in part with larger transverse wrinkles, an intermittent transverse mesh near the frontoclypeal suture and a more regular transverse mesh on the neck. The pronotal disc is covered by a shallow transverse mesh, sculpticell breadth 3–4× length, with the mesh obscured by reflected light. The male aedeagal median lobe is very characteristic, with a narrowly elongate apex and oblique chisel-like tip defined by the oblique apical face (Fig. 30H). Setal formula 2221; standardized body length 4.4–4.9 mm.

This species is known from the higher reaches of Mont Aorai, with the male holotype and female allotype collected near Fare Ata, 1900 m elevation.

This species shares with Mecyclothorax putaputa (Figs 32C, E) the little projected, hitch-like pronotal hind angles with pronotal lateral margins subparallel only outside the basal seta articulatory socket, but individuals of this species are larger, standardized body length 4.7–5.1 mm. The elytral striae are shallow with distinct rounded punctures on the disc that expand the breadth of the striae. The discal elytral intervals are only slight convex. Setal formula 2221. Head with laterally linear frontal grooves, posteriorly lined mesally with fine transverse wrinkles and bordered laterally by fine carina, moderately expanded anteriorly, with two grooves divergent at frontoclypeal suture; eyes convex on protruded ocular lobes, ocular ratio 1.53–1.62 (n = 5), ocular lobe ratio 0.86–0.90; antennae somewhat elongate, submoniliform, antennomere 8 length 1.8× maximal breadth. Pronotum variably broad, moderately transverse to transverse, MPW/PL = 1.14–1.28, base similarly, variably constricted, MPW/BPW = 1.47–1.64; median base evenly depressed relative to convex disc, ~12 distinct punctures each side; anterior transverse impression broad, shallow, continuous across breadth, crossed laterally by ~9 fine longitudinal wrinkles that extend anterad across anterior callosity; front angles not protruded, rounded behind; lateral marginal depression narrow, margin upraised but not beadlike, depression slightly wider inside front angles; laterobasal depression an elongate expansion of lateral marginal depression, crossed near base by transverse bar that connects median base to the upraised lateral margin. Elytra ovate, lateral margin evenly curved posteriorly outside subangulate humerus, the humeri moderately proximate, MPW/HuW = 2.22–2.32; elytral disc moderately convex, sutural interval elevated relative to striae 2–6; striae 1–6 shallow to obsolete near elytral basal groove and humerus; apicad base, stria 6 shallower than striae 1–5, but still continuous, stria 7 interrupted through much of length, consisting of a series of isolated punctures except for deep canaliculated portion apicad fused terminus of striae 5 + 6; eighth interval increasingly more convex as it narrows near apex, appearing pinched, the mesal margin upraised and subcarinate along stria 7 near apex; lateral elytral setae 7 + 6. Microsculpture of frons an elongate transverse mesh, sculpticell breadth 2–4× breadth, the sculpticells visible even in transverse wrinkles, neck with sculpticells 2× broad as long; pronotal disc with indistinct transverse mesh visible outside areas of reflected light, sculpticell breadth 2–3× length; discal elytral intervals lined with regular transverse mesh, the sculpticells distinctly bordered, sculpticell breadth 2–4× length. Coloration of head rufous; antennomere 1 flavous, 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, margins narrowly paler, rufous; elytral disc rufous with a silvery reflection, sutural interval narrowly paler near scutellum, rufoflavous apically; elytral lateral marginal depression concolorous at humerus, contrastedly rufoflavous anterad subapical sinuation; femora rufoflavous, tibiae rufoflavous with brunneous cast.

Male genitalia. Aedeagal median lobe shaft broad, apex moderately extended beyond ostium and broad dorsoventrally (Fig. 30I), the apical face moderately oblique; internal sac with broad, diffuse ventral ostial microtrichial patch (Fig. 30J), flagellar plate elongate, length 0.5× distance from parameral articulations to apical face; dorsal surface of flagellar plate with a broad median depression that includes gonopore, lateral reaches of dorsal membrane associated with plate lightly sclerotized.

Female reproductive tract. Bursa copulatrix ovately expanded apicad a slightly narrower vagina; bursal plus vaginal length twice as long as maximal breadth when compressed under cover slip (Fig. 33C); basal gonocoxite 1 narrow, elongate, with apical fringe of 4 setae, the middle pair doubled, 5–7 smaller setae along mesal margin, 1–3 of these near apex (Fig. 9D); apical gonocoxite 2 very broadly expanded laterobasally, the lateral margin distinctly arcuate laterad the tightly rounded apex, two lateral ensiform setae and one dorsal ensiform seta, the latter extended laterally past lateral margin; apical sensory furrow with two apical nematiform setae and two sensory pegs.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Pito Hito el. 2070 m 2-VI- / 2006 lot 01 pyrethrin fog / 17°36.813'S, 149°27.842'W / E.M. Claridge // HOLOTYPE / Mecyclothorax / ehu / J.K. Liebherr 2013 (black-bordered red label).

Allotype female (MNHN) labeled as holotype.

Paratypes: labeled as holotype (CUIC, 1; EMEC, 1); Pito Hiti, 2000 m el., 17°36.790'S, 149°27.842'W, 2-vi-2006 lot 02, Claridge, pyrethrin fog.