N. brevicornis Sharp, 1882. Designation by Guignot 1946: 115.

(1) Eyes present; (2) metacoxae and metaventrite fused, suture indistinct laterad of noterid platform; (3) noterid platform not extending anteriorly on to metaventrite; (4) protibia with loose rows of spines and setae, lacking large spur at apex and tight comb of small spines on distolateral margin and not expanded distally beyond protarsal insertion; (5) partial fusion of metafurca and metacoxae, not forming complete ring; (6) mid-gular apodeme absent (Beutel and Roughley 1987; Miller 2009); (7) female laterotergite short, posteriorly extending beyond base of gonocoxae (Miller 2009).

As noted by Miller (2009) and others (Manuel 2015 and citations therein), the characters that define Notomicrus are primarily plesiomorphic with the exception of the fusion of the metacoxae and metaventrite. Speonoterus Spangler is also defined by the above character combination, except absence of eyes. Spangler (1996) also noted that the distance from the anterior terminus of the noterid platform (metacoxal lamellae) to the mesocoxal cavities is shorter in Speonoterus, less than the width of the mesocoxal cavities, whereas in Notomicrus, this distance is greater than the width of the mesocoxal cavities (See Spangler 1996; Manuel 2015). Notomicrine species are all notably small (ca. 1.0–1.8 mm). Characters listed above without specific citation have been more common in use for defining Notomicrus (e.g. Sharp 1882; Young 1978; Buetel and Roughley 1987); see Miller (2009) and Manuel (2015) for details.

The josiahi group is diagnosed by the following combination of characters. Dorsal (outer) margin of protibia without notable robust seta at or near mid-length (Fig. 2a). Body form elongate, strongly, but regularly attenuated posteriorly. Eyes large relative to head capsule. Elytra with notable contrasting dark and light colors (Figs 5, 6); shiny and iridescent; microsculpture very fine. Prosternal process narrow (Fig. 3a). Protibiae elongate, with penultimate dorsal seta only slightly longer than others on dorsal margin (Fig. 2a); males with profemur lacking notable protuberance on posteroventral margin (Fig. 2a), only weakly angulate at mid-length; protarsal claws very small, distinctly less than half the length of protarsomere V (Figs 2a, 8, 9), not distinctly larger than female claws, anterior protarsal claw bifurcate, with small dorsal spur (Figs 8, 9). The large eyes, elytral color pattern and coloration and characters of the protibiae, make this species group easily distinguishable from others. There are only two species known.

Venezuela, Amazonas State, Communidad Caño Gato, Rio Sipapo, 4°58.838'N, 67°44.341'W.

Paratypes: “VENEZUELA: Amazonas State/ 4°58.845'N, 67°44.341'W, 100 m/ Communidad Caño Gato on Rio/ Sipapo; sandy stream; 7.i.2006; AS-06-016; leg. A.E.Z. Short” [White label, typed print] (1 female ex. SEMC); “VENEZUELA: Amazonas State/ 4°58.845'N, 67°44.341'W, 100 m/ Communidad Caño Gato on Rio/ Sipapo; 16.i.2009; leg. Short,/ Miller, Camacho, Joly, & Garcia/ VZ09-0116-01X; along stream” [White label, typed print] (1 male, 2 females ex. SEMC) All paratypes with white barcode label with the following numbers and “KUNHM-ENT”: “SM0843570” “SM0831496” “SM0842848” “SM0843672”; all paratypes with “PARATYPE/ Notomicrus josiahi/ Miller, 2013” [Blue label with black border, typed print].

Venezuela: Amazonas State, 4°58.845'N, 67°44.341'W, 100 m, Communidad Caño Gato on Rio Sipapo; 16.i.2009; leg. Short, Miller, Camacho, Joly, & Garcia/ VZ09-0116-01X; along stream (64 males and females ex. SEMC).

TL = 1.46–1.69 mm (mean = 1.59 mm, SD. = 0.058, males = 1.46–1.69 mm, male mean = 1.58, SD. = 0.069, females = 1.55–1.68 mm, female mean = 1.62, SD. = 0.036); TLPn = 1.33–1.53 mm (mean = 1.44, SD. = 0.045, males = 1.33–1.49 mm, females = 1.43–1.53 mm); GW = 0.68–0.78 mm (mean = 0.74 mm, St. Dev. = 0.025, males = 0.68–0.78 mm, females = 0.72–0.78 mm); HW = 0.40–0.45 mm (mean = 0.42 mm, SD. = 0.014, males = 0.40–0.43 mm, females = 0.42–0.45 mm); EW = 0.16–0.19 mm (mean = 0.175 mm, SD. = 0.01, males = 0.16–0.17 mm, females = 0.17–0.19 mm); TL/GW = 1.99–2.31 (mean = 2.16; SD = 0.070; males = 1.99–2.31, females = 2.13–2.22); HW/EW = 2.21–2.53 (mean = 2.39, SD = 0.083, males = 2.41–2.53, females = 2.21–2.44).

Notomicrus josiahi can be diagnosed by the following combination of characters: (1) Size large TL = 1.46–1.69 mm; (2) elytron with strongly darkened region in anterior 1/3^rd, contrasting against brownish-yellow of rest of elytron (Fig. 5a); (3) Eyes very large relative to head capsule (HW/EW = 2.21–2.53; males 2.41–2.53, females 2.21–2.37); (4) aedeagus as in Fig. 6, median lobe expanded on right side in dorsal or ventral aspect, weakly attenuated to apex from mid-length in lateral aspect, with apex curved dorsolaterally to the left, left lateral lobe with dense tuft of setae at apex, few setae along dorsal margin and sparse tuft near base; right lateral lobe with small tuft of setae at apex; (5) pro- and mesotarsal claws as in Fig. 8, anterior protarsal claw strongly bent, bifurcate, with slender spur originating on dorsal margin where curved (Fig. 8a), ventral margin strongly expanded ventrally near base.

Males. Body elongate-oval, attenuated posteriorly (Fig. 5a), TL/GW = 1.99–2.31 lateral outline of elytra and pronotum continuous in dorsal aspect; regularly curved to head, posteriorly evenly attenuated to elytral apex from point of greatest width; widest point just posterior to humeral angles of elytra, as in Fig. 5a.

Color. Head, pronotum, venter and legs yellow; elytron dark brown to black in basal 1/3, darkened region extending posteriorly along elytral suture and contrasting against brownish-yellow color of posterior 2/3 of elytron (Fig. 5a); elytron with surface weakly iridescent. Venter and legs uniformly yellow (Fig. 5b).

Structures. Eyes very large relative to head capsule (HW/EW = 2.35–2.53); antennae with length greater than greatest width of head. Prosternal process narrow, not strongly constricted between procoxae, with apex attenuated (Fig. 3a). Noterid platform with lateral margins subparallel (weakly convergent in posterior 2/3, convergent in anterior 1/3 (Fig. 4a); posterior lobes acute, angled, acutely rounded at apex. Profemur with loose comb of 3–5 stiff setae on anteroventral margin (Fig. 2a), posteroventral margin weakly angled at mid-length (Fig. 2a). Protibia elongate, dorsal and ventral margins weakly divergent distally in anterior aspect (Fig. 2a), anterodorsal margin with row of 6–7 stout setae, without distinctly larger seta near mid-length. Protarsi with adhesive discs on ventral surface of protarsomeres II and III, lacking disc on ventral surface of protarsomere I; protarsal claws as in Fig. 8a, b, subequal in length, small, length ca. 1/3 that of protarsomere V, anterior claw distinctly bifurcate in distal half, expanded basally, very sharply curved, posterior claw slender, weakly expanded basally, moderately curved. Mesotarsi with adhesive discs on ventral surface of protarsomere II only, lacking disc on ventral surface of protarsomere I; mesotarsal claws as in Fig. 8c, d, subequal in length, small, length slightly greater than that of protarsal claws, slender, weakly expanded at base and weakly curved.

Sculpture. Dorsal surface of head with microsculpture very weakly impressed, microreticulation very fine, meshes mostly indistinct; micropunctation nearly indistinct. Pronotum with microsculpture similar to that of head, microreticulation fine; with scattered punctation near base and lateral margin, lateral punctures moderately dense, some with very fine setae. Elytron with microsculpture weakly impressed, microreticulation very fine, nearly indistinct; with punctation sparse in anterior half, with fine punctures along lateral margin and along discal row, with very few to no punctures between discal row and elytral suture, punctate in posterior half, punctures fine, many with very fine setae; discal row composed of fine and irregularly scattered punctures, denser posteriorly, lateral row similar to discal row but more sparse; micropunctation present, evenly scattered. Noterid platform and metaventrite surface with microsculpture weakly to moderately impressed, very fine, meshes of microreticulation nearly indistinct, cells transversely elongated.

Aedeagus. Aedeagus as in Fig. 6. Median lobe in lateral aspect gradually curved from base to apex, dorsal and ventral margins subparallel, converging at apex; apex acute, sharply curved, in ventral aspect subapically expanded and curved to left (Fig. 4a–c). Left lateral lobe in lateral aspect elongate, curved dorsally, with dense tuft of setae at apex (Fig. 6d). Right lateral lobe in lateral aspect oval; apex rounded with small tuft of setae in apical cleft (Fig. 6e).

Females. As males, except eyes slightly smaller than in males (HW/EW females = 2.21–2.39); profemur with posteroventral margin smooth, lacking weak angle at mid-length; pro and mesotarsomeres unmodified, slender, lacking adhesive discs; pro and mesotarsal claws unmodified, claws of respective tarsi subequal in length, slender, weakly curved.

As this species is known from only a single series, it is difficult to assess the degree of intraspecific variation. However, some variation was observed in the relative lightness or darkness in coloration of the individuals, with some brighter in color, more yellow, and others darker in color, more brownish yellow. The darkened region of the elytra also varied somewhat, occupying 1/4 to greater than 1/3 of the basal region of the elytron.

Notomicrus josiahi is among the most easily distinguished species of Notomicrus by the combination of the large eyes, color pattern, shape of male protarsal claws and of male aedeagus. Superficially, N. josiahi is similar to some species of the N. meizon group in color, wherein N. meizon Guimarães & Ferreira-Jr, 2019, N. malkini Young, 1978 and other undescribed species are also darkened at the base of the elytra. However, in N. josiahi, this darkened area is better defined with the posterior border less oblique, thus expanding more completely over the humeral angles of the elytron. More distinctly, N. josiahi differs from these and other species by the much larger eyes and bifurcate protarsal claws (in males), which to date, has only been observed in N. interstinctus, N. brevicornis and the tenellus group. Among all other species of Notomicrus, the aedeagus of N. josiahi is distinct, with the right lateral lobe rounded and bearing a small tuft of setae at apex, rather than without setae, as in all other neotropical species.

Known only from Venezuela (Fig. 10).

This species has been collected from only a single locality, from the margins of a small, sandy stream (Fig. 11a).

Brazil: Amapá, Calcoene, 2.50019, -50.97712.

Holotype, male: “BRAZIL: Amapá: Calcoene/ 2.50019°, -50.97712°; 5 m/ Colcoene (1 km W) on BR-156/ 22.vii.2018; leg. Short; Marshy/ savannah; BR18-0722-01A” [White label, typed print] “HOLOTYPE/ Notomicrus/ interstinctus/ Baca & Short, 2020” [Red label, black border, typed print] (ex.INPA). Paratypes: Same data as holotype, except with “PARATYPE/ Notomicrus/ interstinctus/ Baca & Short, 2021” [Blue label, black borders, typed print] (4 males, 5 females exs. SEMC, INPA); Brazil: Amazonas, Manacapuru Municipality, -3.23037, -60.64269, 35 m, 9.vi.2017, leg. Benetti, margin of large marsh/river, lots of vegetation; BR17-0609-01A; with “PARATYPE/ Notomicrus/ interstinctus/ Baca & Short, 2021” [Blue label, black borders, typed print] (3 males, 6 females exs. SEMC, INPA).

TL = 1.50–1.63 (Holotype = 1.50 mm, mean = 1.56 mm, SD. = 0.045, males 1.50–1.63 mm, females 1.50–1.63 mm); TLPn = 1.38–1.48 (Holotype = 1.40 mm, mean = 1.42 mm, SD = 0.039, males = 1.40–1.45 mm, females = 1.38–1.48 mm); GW = 0.72–0.80 mm (Holotype = 0.72 mm, mean = 0.75 mm, SD. = 0.027, males = 0.72 mm–0.76 mm, females = 0.73–0.80 mm; HW = 0.41–0.45 mm (Holotype = 0.41 mm, mean = 0.43 mm, SD. = 0.013, males = 0.41–0.42 mm, females = 0.42–0.45 mm); EW = 0.18–0.22 mm (Holotype = 0.18 mm, mean = 0.20 mm, SD. = 0.013, males = 0.18–0.19 mm, females = 0.19–0.22 mm), TL/GW = 1.99–2.26 (Holotype = 2.08, mean = 2.07, SD. = 0.074, males = 2.06–2.26, females = 1.98–2.11); HW/EW = 2.04–2.33 (Holotype = 2.28, mean = 2.19, SD. = 0.088, males = 2.16–2.33, females = 2.04–2.26)

Notomicrus interstinctus can be diagnosed by the following combination of characters: (1) Size large TL = 1.53–1.63 mm; (2) elytron dark with contrasting yellow band at mid-length, apices yellow (Fig. 5c, d); (3) eyes very large relative to head capsule (HW/EW = 2.04–2.33; Fig. 5c); (4) aedeagus as in Fig. 7; median lobe not broadly expanded on right side in dorsal aspect, attenuated to apex in lateral aspect, with small, round apical club oriented laterally to left; left lateral lobe with row of setae along entire dorsal margin, only somewhat denser at apex; right lateral lobe glabrous, without small tuft of setae at apex; (5) protarsal claws as in Fig. 9a, b; anterior protarsal claw strongly bent, bifurcate, branching at mid-length, ventral margin somewhat expanded ventrally near base.

Holotype. As described for N. josiahi, except the following. Size large, TL = 1.53 mm. Body very broad, elongate-oval, strongly attenuated posteriorly, TL/GW = 2.08; lateral outline of elytron evenly and gradually curved to apex from point of greatest width, as in Fig. 5c, d.

Color. Dorsal surface of head brown, lighter near clypeus; pronotum yellow; elytron dark, nearly black in anterior and posterior thirds, with lighter contrasting brownish-yellow transverse band near mid-length of elytron, elytral apex also lighter, brownish-yellow; elytron with surface moderately iridescent. Ventral surface of head and prosternum light brownish-yellow; rest of venter yellowish-brown; legs yellow.

Structures. Eyes large relative to head capsule (HW/EW = 2.28). Posterior lobes of noterid platform with angles acute, apices rounded (as in Figs 3a, 5d). Pro- and mesotarsal claws as in Fig. 9.

Sculpture. Elytron with punctation as described in N. josiahi, but denser overall and less restricted to posterior half, with punctures along lateral margin and puncture rows more widely distributed and denser.

Aedeagus. Aedeagus as in Fig. 7. Median lobe in lateral aspect, strongly curved at base, distally weakly curved, nearly straight; dorsal and ventral margins subparallel to mid-length, then attenuated to apex; apex with small club, sharply bent dorsally and left; left lateral lobe in lateral aspect, elongate, dorsal margin curved with dense row of fine setae (Fig. 7d). Right lateral lobe in lateral aspect oblong, rounded distally.

Females. As males, except eyes slightly smaller (HW/EW = 2.04–2.16); profemur with posteroventral margin smooth, lacking weak angle at mid-length; pro- and mesotarsomeres unmodified, slender, lacking adhesive discs; pro- and mesotarsal claws unmodified, claws of respective tarsi subequal in length, slender, weakly curved.

The most notable variation was in size and color, with some specimens darker overall than others, with the yellow bands sometimes smaller.

Notomicrus interstinctus is easily distinguished by the combination of large eyes and elytral color pattern, darkened in anterior and posterior thirds with a yellow transverse band. This color pattern is unique among known species of Notomicrus. This species is also unusual in that it is one of the few known species (along with N. brevicornis, N. josiahi and members of the tenellus group), with males that present bifurcated anterior protarsal claws. The aedeagus, color pattern and more subtly the denser punctation, easily differentiates this species from N. josiahi. The aedeagus of N. interstinctus is similar to that of the N. traili group with the median lobe attenuated and the apex enlarged and bent in a left-dorsal direction, but other external characters, such as the color pattern, tarsal claws and large eyes, readily distinguish this species from the traili group. The elytral punctuation is somewhat similar to that of some members of the N. meizon group, being somewhat densely punctate posteriorly, with punctures fine, but the aforementioned combination of characters will differentiate N. interstinctus from these species as well.

Notomicrus interstinctus sp. nov. derives its name from the Latin adjective interstinctus, meaning checkered or variegated. This refers to the color pattern of the elytra of this species. It is treated as an adjective in the nominative singular.

Known from northern Brazil, Amazonas and Amapá states (Fig. 10).

The species seems to be a generalist in terms of habitat, but seems to prefer vegetated environments. It was collected from a very shallow open marshy area (Fig. 11c) in the Brazilian state of Amapá and the vegetated margins of a river in Amazonas (Fig. 11b).

Notomicrus interstinctus appears very similar to specimens misidentified as N. traili Sharp, 1882 by Guimarães and Ferreira-Jr (2019). This was due to the similarities of the size, punctation and shape of the aedeagus. The records from this work would potentially add to the distribution above, as most appear to be from the same regions of the Amazon Basin as the Amazonas specimens. Verification will be needed to confirm these individual records and these are not formally attributed to N. interstinctus here. Observations of the lone female syntype of N. traili (NHM) indicate that the species is as described by Young (1978), with males attributable to N. traili, appearing as in Fig. 2, with the head and elytra brown, without a pattern.

Members of this species group are most easily identified by their (1) monotone brown elytral color (Fig. 1a–c); (2) rounded, oval body shape; (3) rounded posterior lobes of the noterid platform (Fig. 4b–d); and (4) by their coarser microsculpture, consisting of isodiametric cells, appearing scale-like, rather than as a finer mesh of transversally elongated cells. This latter character is best viewed in light reflecting off the elytra. Even in species with finer variants of the cell-like microsculpture (e.g. N. sharpi), there is no iridescence. Punctation is largely indistinct, except for the discal series and sometimes sporadic punctures posteriorly.

Members of the N. nanulus group present a combination of characters that are variably shared with N. brevicornis, N. teramnus and the members N. tenellus group. This pattern, in tandem with our phylogenetic understanding, for example, tenellus group being sister to all other Notomicrus (Baca and Short 2020), suggest that N. nanulus species are united by a combination of characters that are plesiomorphic at some level within the genus. All share similar microsculpture consisting of isodiametric cells, often appearing scale-like to some degree. However, the N. nanulus group is distinguished from the N. tenellus group by the more rounded body outline (Fig. 1a–c, j) and from the N. tenellus group and N brevicornis by the shape of the noterid platform, with the nanulus group presenting posterior lobes that are rounded or squared (Fig. 4b–d). The rounded/squared lobes of the noterid platform character distinguish the nanulus group from N. teramnus (Fig. 4i) also, but more subtly. The nanulus group also typically presents a noterid platform with more longitudinally-elongated proportions than N. brevicornis (Fig. 4h). Males of the N. nanulus group present unbifurcated anterior protarsal claws, unlike N. brevicornis and the N. tenellus group. The aedeagi of known males of the N. nanulus group are easily distinguished; see Young (1978) and Manuel (2015).

N. chailliei Manuel, 2015; N. femineus Manuel, 2015; N. huttoni Young, 1978; N. nanulus (LeConte, 1863); N. sharpi Balfour-Browne, 1939.

Young (1978); Manuel (2015).

Future work on this group may prove difficult as many species are collected with high ratios of females to males. An example was N. femineus Manuel, 2015, in which extensive collecting yielded only females, raising the possibility of parthenogenetic reproduction. Personal observations indicate that multiple undescribed species are represented by females only. We note that females of this group can be especially difficult to distinguish and are often misidentified as N. brevicornis (see comments on N. brevicornis, below). Notomicrus teramnus is a potential member of this species group based on color, shape and microsculpture, but is treated separately in the key, pending further investigation (see insertae sedis species below).

Non-teneral specimens of this group tend to have the following combination of characters: (1) triangular pigmented area medially on the base of the elytra (Fig. 1g–i), similar to N. josiahi, but not as prominent and not always discernible in some populations or in teneral specimens; (2) dense, fine punctures bearing short setae on the posterior half of the elytra and sometimes extending far anteriorly (not as coarse as in members of the traili group); (3) microreticulation variably impressed, consisting of fine mesh-like reticulation; often iridescent; (4) posterior lobes of noterid platform with squared or rounded angles (Fig. 4e); if posterior angles of noterid platform more acute (Fig. 4f, g), protibia presents robust seta of outer margin approximately at half-length of outer margin, distance between robust seta and dorsoapical angle subequal to distance between robust seta and first seta from protibial insertion (Fig. 2d).

N. malkini Young, 1978; N. meizon Guimarães & Ferreira-Jr, 2019.

Young (1978); Guimarães and Ferreira-Jr (2019).

The meizon group is sometimes difficult to discern from the traili group, as the differences amongst diagnostic characters can be subtle. The darkened basal area of the elytra in the meizon group is helpful, but investigators may find great difficulty in diagnosing teneral members of this group, which often lack the pigmented triangular area on the elytra. It is important to note that this darkened area is truly pigmented, not just darker in appearance due to the folding of the wings under the elytra as often happens in lighter colored species (as in Fig. 1f, j, k). Fortunately, males of most individual species of the meizon group are easy to identify by their aedeagi in combination with other characters, such as tarsal claws. The male median lobes of the meizon group species are usually (but not always) very irregularly shaped (for example, see Young 1978 and Guimarães and Ferreira-Jr 2019). The aedeagus of most species of the traili group appear similar to Fig. 8, with a small club at apex, often hooked to the left (see Young 1978; Manuel 2015; Baca and Short 2018). Additionally, males of meizon species often present notable unequal lengths between the anterior and posterior protarsal claws. These are usually subequal in length in the traili group.

Non-teneral specimens of this group tend to have the following combination of characters: (1) lacking triangular pigmented area on the medial base of the elytra (Fig. 1d–f), lacking maculae; elytra with uniform shades of tan or brown; (2) irregular setose punctures in posterior half of elytral surface with density variable, increasingly coarse if extending on to anterior half of elytron; (3) microreticulation variably impressed, consisting of fine mesh-like reticulation; matte to shiny; elytral surface sometimes somewhat iridescent; (4) posterior lobes of noterid platform with angles acute (Fig. 4k, l); (5) protibia as in Fig. 2e, with robust seta of outer margin at ca. 2/3 length of margin, distance between robust seta and dorsoapical angle distinctly less than distance between robust seta and first seta from protibial insertion.

N. gracilipes Sharp, 1882; N. petrareptans Baca & Short, 2018; N. reticulatus Sharp, 1882; N. sabrouxi Manuel, 2015; N. traili Sharp, 1882.

Young (1978); Manuel (2015); Baca and Short (2018).

Species of the traili group are difficult to discern and constitute a widespread species complex (see Baca and Short 2020). Personal observations coupled with the phylogenetic reconstructions of Baca and Short (2020) show that the diagnostic power of the dorsal punctation (see Young 1978) is unreliable, with multiple clades within the complex sharing similar patterns of punctation; for example, the pattern of punctation attributed to N. gracilipes by Young (1978) arises in multiple places within the complex. The group will require careful taxonomic investigation. The members of the traili group can be difficult to distinguish from those of the meizon group, but mature members lack a pigmented triangular area at the base of the elytra and most males of the traili group have similarly-shaped median lobes of the aedeagus, distinct from the meizon group. See notes in remarks of meizon group above.

Syntypes: Male specimen on small rectangular card, “♂” is drawn around genitalia and other parts, prosternal process flanks the specimen. “Boa Sorta Nov./ Sahlberg 1850” [small rectangular label, handwritten], “Sharp Coll/ 1905-313” [small rectangular label, typed], “Notomicrus/ brevicornis Ind. typ./ D.S.” [small rectangular label, handwritten] “SYN/ TYPE” [small circular label with blue border, printed] (ex. NHM); female specimen on rectangular card, “S. America/ Brazil.” [small rectangular label with blue line across, typed], “Sharp Coll/ 1905-313.” Small rectangular label, typed], “Boa Sorta Nov./ Sahlberg 1850” [small rectangular label, handwritten], “Type 470/ Notomicrus/ brevicornis/ Boa Sorta” [rectangular label, handwritten], “SYN/ TYPE” [small circular label with blue border, printed], “TYPE” [small circular label with red border, printed], (ex. NHM); female specimen disarticulated on large card, “S. America/ Brazil.” [small rectangular label with blue line across, typed], “Boa Sorta Nov./ Sahlberg 1850” [small rectangular label, handwritten], “Notomicrus/ brevicornis, Sharp./ Co-type.” [rectangular label, handwritten], “SYN/ TYPE” [small circular label with blue border, printed], (ex. NHM); female specimen on small rectangular card, “Co-/ type” [small circular label with yellow border, printed], “S. America/ Brazil.” [small rectangular label with blue line across, typed], “Sharp Coll/ 1905-313.” Small rectangular label, typed], “Notomicrus/ brevicornis, Sharp./ Co-type.” [rectangular label, handwritten] “SYN/ TYPE” [small circular label with blue border, printed] (ex. NHM). Note: this latter specimen also with small label “Not brevicornis/ maybe gracilipes?/ Manuel det. 2016”. See notes below.

Notomicrus brevicornis would otherwise appear to be a member of the nanulus group by the aforementioned characters. However, it differs by the more acute posterior angles of the noterid platform, a character shared with members of the tenellus, josiahi and traili groups. The male syntype presents a bifurcate anterior protarsal claw (as in fig. 8A), a character shared by the josiahi and tenellus species groups. With the Old World and New World taxa being reciprocally monophyletic (Baca and Short 2020) and the plesiomorphic appearance of these characters, we would speculate that this species is likely to be sister to one of the New World species groups.

Based on observation of the single male of the syntype series, it is suspected that Young (1978) based his description, key and illustration of the aedeagus of N. brevicornis on the male of a different species. First, the illustration in Young (1978) of the aedeagus of N. brevicornis does not match that observed in the syntype. Second, Young (1978: 288–289) describes N. brevicornis as being sexually dimorphic in elytral punctation, with males being more punctate than females. However, as noted by Sharp (1882: 261), there is very little dimorphism observed between males and females of the syntype series beyond characters of the tarsi. The punctation and sculpture are very weakly dimorphic, both sexes being almost entirely impunctate, except for the weak discal rows and a few scattered punctures near the elytral apex. The punctation is slightly less impressed in females, with discal rows slightly less prominent. The relative difference of punctation between the male and female syntypes of this species is so slight that splitting them up in the key as did Young (1978: 288, couplet 7) seems largely unnecessary, wherein the couplet describing females of N. brevicornis also closely describes the male syntype (Young 1978: 288). The specimens of the UMMZ, observed by Young, were not observed for this study, but the stated differences by Young (1978) and the grouping of males of N. brevicornis with N. malkini in Young’s (1978: 288) key call the identity of the depicted male in Young (1978) into question. Further adding to this suspicion is the fact that some male specimens attributable to N. malkini or other undescribed species of the meizon group in the FSCA were identified as N. brevicornis by Young (date of determination not recorded). For aiding in identification, we have included images of the male syntype, labels and aedeagus (Figs 1k, 12). One specimen of the syntype series appears to be of a different species than the others; likely it is a member of the traili species group. See last listed specimen and note in the examined syntype material above.

Personal observations show that many members of the N. nanulus group are misidentified as N. brevicornis in collections. This is no doubt due to the superficial similarities of N. brevicornis to members of the nanulus group and scarcity of males in the nanulus group. With that, there are likely inaccuracies in literature with respect to records and distributions.

Notomicrus teramnus would also appear a member of the nanulus group, given the above-mentioned characters. An argument could be made that this is the case as it only appears to differ in the shape of the posterior lobes of the noterid platform being more angular than most species in the nanulus group. This species otherwise appears to lack characters that would unite it with other species groups, though this will require examination and/or phylogenetic investigation. We abstain from placing it as member of the nanulus group as N. teramnus is known only from a high elevation hygropetric habitat, which may present confounding morphological specialization. Aedeagal morphology is not here considered to be indicative of a particular placement, but the very unusual morphology of the aedeagus of N. teramnus (see Guimarães and Ferreira-Jr 2019) further raises questions of placement.