A review of the North American genus Epimartyria (Lepidoptera, Micropterigidae) with a discussion of the larval plastron

Abstract The indigenous North American micropterigid genus Epimartyria Walsingham,1898 is revised. Three species are recognized, including Epimartyria auricrinella Walsingham, 1898 which occurs widely over much of the northeastern United States and Canada, a new species, Epimartyria bimaculella Davis & Landry from northwestern United States and Canada, and Epimartyria pardella (Walsingham, 1880) from northern California to northern Oregon. The larva of Epimartyria auricrinella is described in detail, supplemented with illustrations of the external structure of the larval integument. The larval plastron is described and illustrated for Epimartyria, and this is compared with the plastrons of Neomicropteryx Issiki, 1931 and Micropterix Hübner, 1825. COI barcode sequences show that the three species are genetically distinct, congruent with morphological differences. Marked haplotype divergence within some Epimartyria auricrinella populations appears to be unrelated to morphology, geography or phenology.


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The archaic moth family Micropterigidae constitutes the only member of the suborder Zeugloptera and is one of three extant families whose adults are partially characterized as possessing articulated mandibles and in having never developed a coilable proboscis (Kristensen 1998). The oldest fossil remains of Micropterigidae are known from lower Cretaceous Lebanese amber of ~ 140 mya (Whalley 1977(Whalley , 1978. Approximately 21 genera and 160 species of Micropterigidae are now known, with more than 100 additional species recognized but not described (Nieukerken et al. 2011). The family is widely distributed , with no records yet reported from Amazonia, or equatorial Africa. However, the recent discovery of two undescribed genera from lowland (and montane) Costa Rica indicates that the family can also occur in more equatorial, tropical rainforests.
Micropterigidae typically occur in humid habitats where their larvae frequently feed on foliose liverworts or possibly on fungi within rotten logs or soil (Gibbs (2010). Heath (1976) reported larvae of Micropterix Hübner, 1825 at depths down to 10 cm. in loose soil. Occasionally fresh as well as decaying angiosperm leaves may be consumed by larval Micropterix. Lorenz (1961) reared larvae of Micropterix calthella (Linnaeus, 1761) on decayed plant detritus as well as upon fresh leaves of Veronica agrestis L. Carter and Dugdale (1982) found that successful rearing of two species of British Micropterix was dependent upon a supply of fresh, photosynthetic angiosperm tissue, particularly chickweed (Stellaria media (L.). The number of larval instars is known to vary between 3 in Epimartyria (Tuskes and Smith, 1894) and 4 in Micropterix (Klausnitzer et al, 2002), Kurokopteryx Hashimoto, 2006and Neomicropteryx Issiki, 1931, (Hashimoto 2006. Adult Micropterigidae are known to feed on plant pollen from a broad range of angiosperm families (Zeller-Lukashort et al. 2007). Members of the southwestern Pacific Sabatinca group have also been reported feeding on fern spores (Kristensen 1998, Gibbs 2010). Adults of a few new species of Micropterigidae have been recently discovered in Costa Rica feeding on fern spores (Wagner and Davis in prep.).
Major portions of the larval integument of Epimartyria auricrinella have been found to be densely covered with minute, irregularly shaped micropapillae (Davis 1987). Because the minute size and distribution of these cuticular structures closely resemble those of other insects known to inhabit aquatic or occasionally flooded habitats, it is believed that portions of the integument of Epimartyria may also serve in assisting respiration as has been demonstrated in those species (Thorpe 1950, Hinton 1969. These specializations are discussed further under the larval morphology of E. auricrinella. Five monophyletic lineages have been determined within the Micropterigidae based on analysis using the 16S rRNA gene (Kobayashi et al. 2000, Gibbs et al. 2004. Epimartyria is a member of the northern hemisphere group which is represented by five genera in Japan: Issikiomartyria Hashimoto, 2006, Kurokopteryx, Neomicropteryx, Palaeomicroides Issiki, 1931, and Paramartyria Issiki, 1931, with a single genus each known from Vietnam (Vietomartyria Hashimoto & Mey, 2000), and North America (Epimartyria) (Gibbs 2010). numbers are listed in Appendix 1. Neighbour-Joining (NJ) trees for all barcode data were constructed using the quicktree algorithm (Howe et al. 2002) and under the Kimura two-parameter (K2P) model of base substitution (Kimura 1980). Genetic distances were estimated with MEGA 5.05 (Tamura et al. 2011) using the K2P model. Maximum parsimony (MP) analyses was performed with PAUP* 4.0d100 (Swofford 2003) on selected sequences representing distinct haplotypes. Only full-length barcode sequences without ambiguous sites were analyzed. Heuristic searches for MP analysis were carried out with all positions equally weighted and under the tree bisection-reconnection (TBR) swapping algorithm with 100 random addition sequences. Bootstrapping of 1000 replicates was conducted under the parsimony criterion with the default setting starting with a random seed and the TBR branch-swapping algorithm.
Bremer support values were calculated using Treerot v.3 (Sorenson and Franzosa 2007). Haplotype diagrams were constructed in TCS 1.21, with a 95% confidence limit for parsimony (Templeton et al. 1995). Shorter sequences or those with ambiguous bases were excluded from the haplotype analysis.

Type species. Micropteryx pardella Walsingham, by original designation.
Diagnosis. Epimartyria appears closely allied to the Asian genus Paramartyria as suggested by the similar elongate process arising from the inner base of the male valvae (Fig. 78) and by similar larval chaetotaxy (Hashimoto 2006). More significantly, close affinities of these two northern genera were also indicated from the molecular study initiated by Kobayashi et al. (2000) and Gibbs et al. (2004), based on the 16S rRNA gene. At least one species of the Asian genus Vietomartyria, V. nankushana Hirowatari & Hashimoto (Hirowatari et al. 2009), also posseses a similar basal process on the valva, as pointed out by one reviewer. The forelegs of Vietomartyria also lack an epiphysis as do two species of Epimartyria. Epimartyria differs from all other micropterigid genera in possessing a deeply divided phallus, and from Paramartyria in particular by possessing a pair of lateral projections near the apical one third of the distal phallus and in having tergum X divided into dorsal and ventral processes (Hashimoto 2006). Hashimoto (2006) also mentioned the presence of an epiphysis in Paramartyria as one feature that distinguishes the latter from Epimartyria. Two of the three species of Epimartyria lack an epiphysis, but an epiphysis is present in E. pardella (Fig. 17).
Thorax: Scales of mesonotum broad, appressed. Metanotum mostly naked except for a few long, piliform scales. Tegulae rather sparsely covered with long piliform scales. Forewing length: 4.2-5.5 mm; forewing ( Fig. 16) with humeral vein present; Sc deeply bifurcate; R simple; Sc-R crossvein present near fork of Sc; Rs with 4 veins; Rs3-4 fused to ~ basal 1/3; accessory cell present; M with 3 branches; 1A and 2A fused over distal half; 3A extending across base of moderately small jugal lobe. Wing scale morphology of the primitive, generally non-glossatan type (Kristensen and Simonsen 2003) consisting of fused dorsal and ventral surfaces (without internal chambers), and with a herringbone pattern formed by oblique-longitudinal crests overlying a dense layer of transverse microribs . Hindwing venation similar to forewing except with Sc and R fused; 1A and 2A completely fused; anal crossvein connecting to CuP near distal 2/3; scales over distal third of hindwing dark fuscous and nearly as broad and iridescent as in forewing; scales gradually becoming more slender, gray, and without iridescence over basal 2/3. Legs (Fig. 17) with tibial spur pattern of 0-0-4; a short epiphysis ~ 1/3 the length of tibia arising slightly beyond its midlength present in E. pardella; epiphysis absent in E. auricrinella and bimaculella; consisting of a pair of strongly curved claws; a lateral pair of pad-like pulvilli densely covered with long spinose setae; a median arolium with apical surface densely lined with minute grooves (Fig. 27); pseudempodial seta ( Fig. 25) with longitudinal grooves.
Abdomen: Cuticle dark brown, sparsely covered with long, piliform scales. A pair of glands present, opening on sternum V in both sexes (Philpott 1925); glands similar to those present in Paleomicroides, Paramartyria, and Neomicropteryx in not protruding and possessing a narrow slit-like opening within a smooth, hyaline area (Kristensen 1984a).
Male genitalia: Tergum X (uncus) ~ half the median ventral length of IX; apex deeply divided nearly half its length into two broad lobes. Sternum X (venter X) variously bilobed, with or without short lateral lobes. Segment IX a completely sclerotized ring, with dorsal median length ~ 1/6 of ventral length. Sternum IX (vinculum) a broad plate with subparallel lateral margins; anterior end as broad or broader than caudal end. Valva with a subacute to rounded apex; base of valva with a long digitate process from mesal surface. Medial plate (juxta) with a slender stalk-like base gradually expanding anteriorly to a small, flat, oval plate. Distal phallus divided into two slender branches ~ half the total length of phallus; shorter dorsal branch of phallus terminating in gonopore (phallotreme) with thickened radial folds; a pair of minute, acute spines present laterally near distal third of dorsal branch; apex of longer ventral branch densely covered with numerous minute flattened scutate processes with rounded apices directed basad; phallobase moderately inflated, as long as or slightly longer than divided branches.
Female genitalia: Abdominal segment IX a complete ring with mid dorsal length ~ 0.5-0.6× the mid ventral length. Segment X consisting of a pair of lateral, setose plates; cloaca ending terminally; X often telescoped into IX and VIII in repose. Apophyses absent. Genital chamber with thickened walls surrounding a variably shaped slerite; caudal end of sclerite furcate. Ductus spermatheca with a moderately enlarged, spindle-shaped reservoir (utriculus) located at varying distances along ductus. Corpus bursae gradually enlarging anteriorly, membranous, with four tridentaform signa equally spaced around middle of corpus bursae; enlarged bases of signa projecting externally beyond wall of corpus bursae, with spinose branches projecting internally.
Remarks. For many years John Heath, formerly employed at the Experimental Research Station at Monks Wood in England, pursued research on the family Micropterigidae, resulting in about 20 papers on this group (Emmet 1987). Heath had partially completed a revision of the genus Epimartyria, but this was never published. We had not viewed a copy of this manuscript until our publication was in review. In his manuscript, Heath recognized an additional new species from New Jersey, based on specimens collected at Essex County Park by W. D. Kearfott. Our studies found no morphological justification for this species.
Because this is the first taxonomic revision of Epimartyria, there remain some gaps in our knowledge about their biology which cannot be answered with available material and evidence.

1
Forewing without spots, uniformly dark fuscous with coppery to purplish luster ( Fig. 1)  Diagnosis. Adult E. auricrinella are easily distinguished from those of the other members of Epimartyria in possessing uniformly dark fuscous forewings without the yellowish spots present in those species.
Thorax: Dark fuscous with coppery to purplish luster. Tegula concolorous with head. Forewing dark fuscous with coppery or golden to purplish luster dorsally, less iridescent ventrally; fringe paler, more gray. Forewing length: 4.2-5.6 mm. Hindwing with scales over distal third nearly as broad, dark fuscous and iridescent as in forewing; scales gradually becoming more slender, more gray, and less iridescent over basal 2/3; fringe gray. Legs medium to dark brown dorsally, light brown ventrally and at apices of tarsomeres; epiphysis absent.
Abdomen: Piliform scales uniformly brown dorsally and ventrally. Paired glands of sternum 5 with muscle for opening glands originating on anterior edge of sternum 6 and inserted into each gland duct just inside aperature; gland reservoir slightly larger and more ovoid in female, but surrounding layer of secretory cells better developed and 2-3× thicker in female (Djernaes 2011, Djernaes andSperling 2011).
Male genitalia (Figs 74-78): Caudal lobes of tergum X broadly rounded. Caudal apex of sternum X deeply divided, with apex of lobes acute, recurved; a pair of short, lateral lobes present near base. Valvae moderately long, ventral length nearly half the maximum length of segment IX; apex subacute and bearing a short, slender, recurved spine; a short, triangular, rounded process arising midway from mesal surface; elongate basal process ~ 4/5 the length of valva; distal margin of valva variable within populations from slightly concave to convex (Figs 78a-d). Dorsal branch of phallus cylindrical and smooth.   sive plastron surface laterally (Fig. 52). Primary setae longitudinally ribbed, moderately slender, long, clavate.
Head: Prognathous and capable of being retracted into prothorax. Antenna elongate, slender, 3-segmented, arising posterior of clypeal margin and dorsal to stemmata;    Haplotype network for 10 distinct haplotypes detected in two species of Epimartyria (7 for E. auricrinella, 4 for E. bimaculella). Circles are labelled with the haplotype name (capital letter), and the number of specimens per haplotype; lower case letters refer to localities indicated on the distribution map (Fig. 32). The single sequence of E. pardella, which separated out, is not shown. second segment the longest, ~ 2× the length of basal segment; all antennal segments without sensory setae except for elongate terminal spinose seta. Five stemmata present, arranged in a tight circle. Adfrontal sutures vestigial, not extending to vertex; adfrontal ridges similarly undeveloped. Ecdysial lines externally indistinct. Tubular spinneret absent; external opening of labial salivary gland circular, relatively large, diameter ~  equal to length of second segment of labial palpus. Cranial setae reduced in length and number and concentrated over anterior third of head; stemmatal setae absent; a single medial (M) seta arising midway between antennae, without homology in other Lepidoptera but possibly homologous to campaniform sensillum in Trichoptera larva (Kristensen 1998). Labrum with 6 pairs of primary setae and numerous spines along anterior margin; seta La 1 arising distad of anterior margin of labrum (Fig. 38). Mandible generally triangular in form with 3 acute cusps, the basal-most cusp the most reduced. Maxillary palpi relatively well developed, 3-segmented, with apical sensillae as in Fig. 46. Labial palpi reduced, 3 -segmented with minute apical segment bearing a long sensillum (Fig. 47). Intersegmental membrane between head and thorax covered with flattened, multidentate, scutate outgrowths .
Thorax: Prothorax with 7 primary tactile setae and 4 peg-like microsetae, the latter located along anterior margin of prothorax near the head-prothoracic fold; XD1 and XD2 greatly reduced to peg-like microsetae along dorso-anterior margin of prothorax below D2; L1 posterior to XD1; L2 below L1 and anterior to spiracle. MV1 and MV2 short, peg-like, below SV2 and closer to anterior margin of prothorax; MV2 about 2 × length of MV1. Subdorsal setae absent on all body segments. Meso-and metathorax with 5 primary setae and one microseta (SV2); L1 and 2 well developed and equal in size. Legs with 3 well defined segments and large pretarsal segment; 4-segmented including reduced coxa; pretarsal claw curved, elongate, ~ 1/3 the length of remainder of leg; axial spine at base of claw well developed; femur and trochanter fused, as well as tibia and tarsus; coxa with a bilobed and possibly eversible tactile vesicle located posterior-mesally near base of femur (Figs 48-49); Abdomen: Segments 1-8 with 4 primary setae and 2 peg-like (L2) to spherical microseta (SV2); segment 9 with only D1 and L1; segment 10 with 2 microsetae, possibly representing D1 and L1. Spiracles peripneustic, located anteriorly in intersegmental fold on segments 1-8; spiracle raised to form a small dome with walls subdivided into ~ 10-12 fimbriated bands. Abdominal segments 1-8 with short, fleshy, nonmuscular prolegs with rounded apices (Fig. 50); crochets absent in all genera of Micropterigidae, Larval hosts. Hepaticophyta: Lepidoziaceae: Bazzania trilobata (L.) S. Gray. Pupa. Unknown. Biology (Figs 9-10). The species occurs in shaded locations, in wet swampy woods, boggy ditches, or creek sides where leafy (moss-like) liverworts, the probable larval host, grow. Such habitats can be periodically or seasonally flooded. Larvae possess a plastron which indicates the capacity to live for short periods in a subaquatic environment or, at least in a habitat that is water-saturated. Adults are diurnal and are best obtained by gently sweeping the understory or clumps of liverworts (Landry and Landry 1992). They can be seen perched on low foliage during the day and can be active even in early morning after sunrise (Figs 1-2). Mating was observed in the afternoon between 1200-1700H (JFL pers. obs.). Larvae obtained (by JFL) by placing in a Berlese funnel clumps of the liverwort Bazzania trilobata collected on 3 September 2000 at Lac Brûlé (Quebec) yielded larvae of two different size classes (3.4 mm vs 1.8 mm overall body length). This supports the previous observations by Davis (1987) that larval development probably spans over two years, at least in the northern part of the range, although adults emerge every year. One larva was found on the tip of a liverwort leaflet at the same locality in early October when the air temperature was around 5°C. Adults generally begin to emerge in mid May in the southern part of their range (Georgia, North Carolina) with April 30 being the earliest date recorded (from southern Maryland near Washington, DC). Further north the flight period is gradually delayed, with adults in northern New York and all of Canada active during the summer between mid-June and mid-July.
Holotype   Distribution (Fig. 32). Epimartyria auricrinella occurs widely over eastern North America, in Canada from Nova Scotia to Ontario, and in the U.S. from Maine to Michigan and south to Tennessee and Georgia.
Remarks on larval morphology. Chaetotaxy: Because the larvae of Micropterigidae lack some thoracic and abdominal setae present in higher Lepidoptera, determining the homology of those setae present is subject to uncertainty. Various assumptions have been made as to which setae are present, based in part on their position to longitudinal muscle groups or to various body ridges (Hashimoto 2001(Hashimoto , 2006Gibbs 2010), as well as to the generally accepted chaetotaxy of glossatan Lepidoptera (Hinton 1946, Stehr 1987 which was followed by Davis (1987). Greatest uncertainty persists with the prothoracic chaetotaxy, where the number and relative development of setae can vary between different genera of Micropterigidae. Hashimoto (2001) concluded that the XD (of the prothorax) and the SD groups are absent in Micropterigidae, with the possibility that the two most dorsal of the four pairs of peg-like microsetae along the anterior margin of the prothorax in Epimartyria could be vestiges of one or more of these groups. The more ventral of the two microsetae along the anterior margin of the prothorax are believed to represent MV1 and MV2 present in most Lepidoptera, but homology of the dorsal pair is questionable. Because microsetae in this region are not known to occur on the prothorax of other Lepidoptera (Hinton 1946), we have considered the dorsal pair to be homologous to XD1 and XD2 as suggested by Hashimoto (2001). Hinton (1946) briefly discussed the possibility that the XD group in higher Lepidoptera might be homologous to the microsetae of other body segments, but he argued that long tactile setae along the front margin of the prothorax represented instead a special setal group essential for protecting larvae, especially in those species with prognathous, retractable heads. In Micropterigidae it appears as if this protection has been compensated by several of the prothoracic tactile setae being directed strongly forward (Fig. 33). It may also be possible that several proprioreceptor (microscopic) setae homologous to those of higher Lepidoptera do not occur in Micropterigidae, and that all or most of the relatively stout microsetae present may represent greatly reduced tactile setae. Such reductions have occurred with the abdominal L2 and SV2 setae of Epimartyria (Fig. 33), D1 and D2 of Austromartyria (Gibbs 2010), and D2 of Agrionympha (Gibbs and Kristensen 2011). All microsetae of Epimartyria auricrinella are similar to the prothoracic microsetae in being relatively stout and greatly reduced it length (Fig. 33). Consequently, in this study we have largely followed the protothoracic chaetotaxy proposed by Hashimoto (2006) for the closely related genera Paramartyria and Neomicropteryx. The number and distribution of the prothoracic microsetae have not been well studied or illustrated in most genera of Micropterigidae. Better resolution of the prothoracic setal homology might become possible as larvae of more genera are discovered and studied.
Prolegs: The larval prolegs of Micropterigidae, which occur on abdominal segments 1-8 and 10, differ in their morphology from those of all other Lepidoptera where crochet-bearing prolegs are typically present only on segments 3-6 and 10. Hinton (1958) also reported muscles to be lacking in micropterigid prolegs, although this probably should be examined further in some genera such as Micropterix where the prolegs appear more developed and with more melanized, acute, clawlike apices (Figs  66-68). The anal prolegs of Micropterix are also distinct in forming a relatively broad, trilobed sucker ( Fig. 66; Zeller-Lukashort et al. 2007).
Integumental specializations: Larvae of Micropterigidae often occur close to the ground in habitats more likely to be subjected to periodic flooding and drying. As an adaptation to such conditions, the larvae have developed an unusual cuticular morphology in the form of a physical gill, or plastron (Thorpe 1950, Davis 1987, which provides extensive air-water interface for gaseous exchange. The aquatic larvae of several species of Crambidae have also developed special gills and plastron cuticles for breathing underwater (Wichard et al. 2002).
An extensive plastron area has been observed in Epimartyria (Davis 1987), and similar cuticular structures with various modifications appear in other genera of Micropterigidae examined. The plastron in Epimartyria auricrinella extends as a broad band laterally around the body between the level of the lateral (L1) and subventral (SV1) setae and then dorsally over the posterior margin of the prothorax (Fig. 33). The abdominal spiracles are located near the dorsal margin of the band at the extreme anterior edge of the segment (Fig. 52). The surface of the integument within this zone is densely covered with minute, irregularly shaped micropapillae (Figs 52, 55). Radiating out between adjacent micropapillae are dense series of even smaller ridges, aligned ~ 0.4-1.0 µm apart. Each ridge bears a single row of elongate, erect, knobby microtubercules ~ 0.2-0.4 µm in diameter and ~ 0.8-1.2 µm in length (Fig. 56). These minute structures are believed to help form an air film around that portion of the body (when submerged) that excludes water under normal hydrostatic pressure. Minute openings in the epicuticle are visible between the ridges (Fig. 57). These lead internally into an unusually complex, multichambered exocuticle reported by Kristensen (1990Kristensen ( , 1998 in the larvae of Sabatinca and Micropterix. The basal layer of the exocuticle was found in these genera to possess small pores in each chamber which opened into a fluid-filled space between the exo-and endocuticle. Kristensen hypothesized the function of these unique cuticular specializations may be to assist in maintaining a water balance for larvae in a habitat subjected to periodic drying. An extremely thin, extracuticular pellicle covers much of the dorsal, lateral, and part of the ventral larval trunk to which small particles may adhere. The function and origin of the pellicle remain unknown. Immediately beneath the abdominal pellicle of E. auricrinella the exocuticle is divided into a series of honeycombed chambers (Fig. 58) resembling the condition Kristensen discovered in the larvae of Sabatinca and Micropterix.
The multidentate, scale-like cuticular outgrowths (Figs 41-42) covering the intersegmental membrane between the head and prothorax of Epimartyria auricrinella may further assist in a respiratory function. These structures superficially resemble the plastron scales present in certain Coleoptera (Hinton 1969(Hinton , 1976. The spiracles in Epimartyria (Figs 53-54) are also modified to prevent water entry. Each spiracle is raised into a small dome with finely divided, fimbriated walls. The spiracles in later instars of Neomicropteryx larvae are also conical with fimbriated walls, but the spiracular walls of the first instar are completely fused (i.e., solid) (Hashimoto 2006) as they are in later instars of Sabatinca and Micropterix (early instars not examined). Spiracles of the first instar of Epimartyria have not been examined but may be similar to those of Neomicropteryx.
The larval plastron of Neomicropteryx nipponensis Issiki is similar to that of Epimartyria auricrinella in possessing a dense zone of minute, irregularly shaped micropapillae interconnected by dense radiations of smaller ridges bearing rows of knobby microtubercules (Figs 60-62). Scutate outgrowths also arise from the intersegmental headprothoracic membrane (Fig. 63) as in Epimartyria. It is likely that larvae of all members of the northern hemisphere group of micropterigid genera proposed by Kobayashi et al. (2000) and Gibbs et al. (2010) have developed similar plastron specializations. In contrast, the external surface of the exocuticle of Micropterix (Figs 70-72) possesses a more extensive, regular arrangement of micropapillae, each ~ 10-20 µm in diameter, with ~ 6-8 relatively stouter, often bifurcate, arm-like ridges radiating from a central disk. The ridges in Micropterix do not continue with those of adjacent ridges, but the extremities of each ridge are densely covered with microtubercules. Minute openings of variable size are present in the exocuticle of Micropterix (Figs 71-72), similar to those observed in Epimartyria and Neomicropteryx. Epimartyria bimaculella sp. n. urn:lsid:zoobank.org:act:6A40EFD1-BC6D-4DF3-AB1C-D4031870E61D http://species-id.net/wiki/Epimartyria_bimaculella Figs 2,[6][7]11,32,[81][82][83][84][85][86][87] Diagnosis. Adults of E. bimaculella most resemble those of E. pardella in possessing dark fuscous forewings marked by pale golden spots. A total of two yellowish spots occur in bimaculella, with only a single large costal spot present beyond the middle of the forewing. Four spots are present on the forewing of pardella, with two of these located across the distal third of the wing on the costal and dorsal margins respectively.
Thorax: Dark fuscous with coppery to purplish luster. Tegula concolorous with head. Forewing mostly dark fuscous with coppery to purplish luster dorsally, marked with two pale yellowish spots; the largest, irregularly oval to rectangular spot extends from the costa approximately halfway across the distal third of wing; a second smaller, more slender spot extends diagonally from about midway along dorsal margin to midway on discal cell; a slight suffusion of pale yellowish scales may be sometimes evident at the base of the forewing, but only seldom does this occur; forewing less iridescent ventrally; fringe pale yellow along termen, fuscous along dorsal margin. Forewing length: 4.6-5.3 mm. Hindwing mostly gray, becoming darker and slightly iridescent toward apex; fringe gray. Legs medium to dark brown dorsally with a slight purplish luster, light brown to cream ventrally; epiphysis absent.
Male genitalia : Tergum X similar to E. auricrinella, broadly bilobed. Caudal apex of sternum X deeply divided, with apex of lobes acute, only slightly curved; a pair of short, lateral lobes present near base. Valva moderately long, ventral length ~ half the maximum length of segment IX; apex subacute and bearing a short, slender, recurved spine similar to E. auricrinella; a short but broader and more triangular, rounded process arising midway from mesal surface; elongate basal process ~ 4/5 the length of valva; distal margin of valva variable within populations from slightly convex to ~ straight. Dorsal branch of phallus cylindrical and smooth.
Female genitalia (Figs 86-87): As described for genus. Caudal end of genital sclerite moderately furcate as in E. auricrinella; length of furcations ~ 0.3 that of moderately long, undivided base.
Larva and pupa. Unknown. Biology (Figs 6-7, 11). At the type locality, specimens were captured by sweeping low lying vegetation or during diurnal flight along a shaded seepage in a Douglas Fir-Western Red Cedar forest where leafy liverworts grew. Adults were also observed perching on lower parts of plants such as Salmonberry (Rubus spectabilis Pursh) no more than approximately 25 metres from the liverwort habitat (D.G. Holden, pers. comm.). In different parts of the range, specimens were collected from late April to mid August, with most records in June. Late records (July and August) are from higher elevations.
Holotype  Distribution (Fig. 32). Epimartyria bimaculella is known from northwestern Washington and southern British Columbia. Most British Columbia records are from the southwesternmost corner in the periphery of the Vancouver area, reflecting a more intense collecting effort in that region. One record from the Rocky Mountains of Glacier National Park, BC suggests a significantly broader distribution.  Etymology. The species name is derived from the Latin bi; (two, double) and maculella (little spot) in reference to the two, small, pale yellowish spots present on the forewings.

Diagnosis:
Adults of E. pardella most resemble those of E. bimaculella in possessing dark fuscous forewings marked by pale golden spots. Four spots are present on the forewing of pardella with two of these located across the distal third of the wing. In contrast, a total of two yellowish spots occur in bimaculella, with only a single large costal spot present beyond the middle of the forewing. In the male genitalia, the caudal lobes of sternum X (uncus) are more simple than those of the other members of Epimartyria in consisting of more shallow, rounded lobes compared to being curved and more slender in the males of auricrinella and bimaculella. Adult (Figs 3, 8). Head: Vestiture light orange brown. Antenna with vestiture of scape and pedicel concolorous with head; scales of flagellum pale golden yellow. Labial palpus pale brown to cream.
Thorax: Dark fuscous with coppery to purplish luster. Tegula concolorous with head. Forewing dark fuscous with coppery to purplish luster dorsally, marked with four, pale yellowish spots; the largest, irregularly rectangular and slightly oblique spot extends from costa approximately halfway across the distal third of wing; a smaller, more oval spot opposite costal spot on dorsal margin; an oblique basal spot arising midway along dorsal margin and extending halfway across wing to base of radial vein; a fourth, smallest spot at base of wing; forewing less iridescent ventrally; fringe pale yellow along termen, more gray along dorsal margin. Forewing length: 5.0-5.5 mm. Hindwing mostly gray, becoming darker and slightly iridescent toward apex; fringe gray; fringe light to dark gray. Legs medium to dark brown dorsally, paler brown ventrally and over tarsomeres; epiphysis present, ~ 1/3 the length of foretibia and arising slightly beyond its midlength.
Abdomen: Piliform scales light to dark brown. Male genitalia : Tergum X with more slender caudal lobes. Caudal apex of sternum X (gnathos) not deeply divided, with short, triangular caudal lobes and without accessory lateral lobes. Valva short, ventral length less than 1/3 the maximum midventral length of segment IX; apex rounded and bearing a short, stout subapical spine; mesal surface smooth, without median process; elongate basal process nearly equal to length of valva. Dorsal branch of phallus more depressed, with subapical margins bearing short, paired spines, gonopore with less thickened radial folds than in previous two species.
Female genitalia: (Figs 93-96): As described for genus. Caudal end of genital sclerite deeply furcated; length of furcations exceeding length of short, undivided base. Egg. White; dimensions 0.44 × 0.44 mm. Tuskes and Smith (1984) report the ova are flattened, circular and smooth when first deposited but soon become spherical and covered with numerous minute projections similar to those reported for Micropterix calthella (L.) by Lorenz (1961). The eggs were observed to hatch in 21 days at 22°C.
Larva. Not examined. The following description has been summarized from Tuskes and Smith (1984): Body length 4.3 to 4.6 mm; width 1.4 mm; height 1.2 mm. The body tapering at both ends with highest and broadest point at abdominal segment 4. Dorsal and lateral surface brown to dark brown, ventral surface light brown.
Head. Length 0.5 mm, diameter 0.27 mm. Brown. Antennae prominent, 3-segmented and situated on small tubercles located on dorsal lateral portion of head. Stemmata with 5 facets and located near base of antenna. Labrum simple with a pair of 3-segmented palpi. Mandibles simple and dark brown. Head diameter of first and second instar larvae 0.11 and 0.22 mm, respectively.
Thorax: Prothorax distinctly narrower than mesothorax. Prothoracic shield with 10 peg-like setae, 8 on the anterior and lateral border and 2 dorsally. Mesothorax with 8 setae, 6 on dorsal and lateral anterior portion of gray brown pigmented area, and 2 just ventral to this pigmented area. Setae of metathoracic segment similar to those of mesothorax except subdorsal (D2) seta is greatly reduced in size. All thoracic segments have additional small micro-seta just dorsal to each true leg. Thoracic legs brown, with 3 segments (excluding coxa) and simple claw.
Abdomen: Abdominal segments Al to A8 (and T2 and T3) with serrated knobs which form a dorsal and lateral ridge; areas between ridges concave. The mid-dorsal area concave with a small dark depres sion present on posterior of segments T2 to A8. Segments Al to A8 each with one dorsal seta (length 0.18 mm) atop dorsal ridge. Segments Al to A8 with reduced, almost microscopic subdorsal (D2) seta (length 0.04 mm) and prominent lateral seta (length 0.12 mm) on lateral ridge. Dorsal. subdorsal and lateral setae occur in brownish pigmented area which has rough and wrinkled appearance. Dorsal and lateral intersegmental area constricted and may contain series of 8 to 20 microscopic dots. Cuticle ventral to lateral ridge smooth and light brown. Series of brown dots form pattern around protuberance that usually support a small seta. Conical ventral prolegs occur on segments Al to A8, with a small, sclerotized protuberance present on ventral surface of each. Segments A9 and Al0 fused and with enlarged simple sucker. Spiracles posterior and ventral to lateral setae.
Pupa. Not examined. Exarate, decticous; white to light brown. Cocoon. Not examined. Brown, oval in general form, measuring 5.5 × 4.5 mm; primarily of silk with small fragments of vegetation attached.
Biology (Fig. 8). Tuskes and Smith (1984) observed the eggs of E. pardella to be deposited in June on the underside of liverwort thalli singly or in small clusters of up to five eggs. They are white, measuring ~ 0.40 × 0.44 mm, and are flattened, circular, and smooth when first deposited but become spherical within a short time and covered with a series of small projections. First instar larvae ~ 0.75 mm long were reported to emerge in about 21 days (at 22°C). The larvae are rather inactive (in captivity) and are usually found on the underside of the thalli during the day. When disturbed or inactive the head may be withdrawn into the thorax. Pupation occurs within a thin walled, tightly woven brown cocoon close to the ground and attached to vegetation with strands of coarse silk.
Adults begin to emerge in late May with the flight season ranging from late May to mid-July and peak flight activity in June at the Prairie Creek State Redwood Park locality. Tuskes and Smith reported the adults to be relatively inactive, remaining motionless for hours and seldom travelling more than 30 cm. They are known to be diurnal and most active between 0900 and 1930 h. Adult feeding by E. pardella has not been reported, but the adults were observed drinking water by lowering their heads to the moisture. Moths can die in less than two days if deprived of moisture but may survive in captivity from 9 to 18 days when provided with water.
Tuskes and Smith concluded that E. pardella possessed a two year life cycle similar to that proposed for E. auricrinella (Davis 1987). In captivity eggs deposited in June 1981 became adults in June 1983. In the field they frequently collected second instar larvae during the adult flight period.
Lectotype. ♂ (present designation), "OREGON: Klamath Co: nr. Redwood Creek, Coast: 26 June 1872, Wlsm. 90591; B.M. Genitalia Slide No. 25352; Epimartyria (= Micropteryx Wlsm.) pardella Wlsm. PARATYPE; Lectotype ♂, Epimartyria pardella Wlsm. (BMNH)." The lectotype has been selected from a series of five syntypes collected "on the borders of the forest of "redwood" (Taxodium sempervirens) near the coast, in southern Oregon, at the beginning of June 1872" (Walsingham 1880 Distribution (Fig. 32). Epimartyria pardella is known from northwestern California and northern Oregon. California localities and the type locality in Oregon are near the coast in redwood forests. The most northern Oregon locality occurs in the Columbia River valley.
Remarks. Information included in this report on the immature stages and life history of E. pardella has been quoted or summarized from the thorough study of this species by Tuskes and Smith (1984) at the Prairie Creek State Redwood Park, California. In addition to possible color differences, two major morphological differences noted in their description of the larva of E. pardella from that observed for E. auricrinella include: (1) 10 versus 11 (in auricrinella) peg-like setae on each side of the prothorax, and (2) D2 of metathorax and abdominal segments 1-8 greatly reduced in pardella (as reported also in Austromartyria, Gibbs 2010, and for the abdomen in Agrionympha, Gibbs and Kristensen 2011). Although examples of the larva, pupa, and cocoon of this species were reportedly deposited in the collections of the California Academy of Sciences, San Francisco, CA by Tuskes and Smith (1984), attempts to locate and borrow this material for study were unsuccessful. The skeletomuscular anatomy of the male genitalia of E. pardella was reviewed by Kristensen (1984b).

DNA barcoding
A total of 44 specimens yielded barcode sequences, of which 40 were full-length at 658 bp (Appendix 1). Geographic representation of barcoded specimens was primarily dictated by the availability of recently collected material (<20 years), and consequently restricted to a few localities which do not represent the entire range of the species (Fig.  32). Three barcode sequences of Epimartyria were available in GenBank, two for auricrinella and one for pardella (from Lees et al. 2010). The auricrinella sequences were identical to haplotype A1 from specimens collected at Gatineau Park, QC, a locality from which a series was examined but not barcoded (see 'Material examined' under auricrinella). The pardella sequence was one base pair different from haplotype P1 from a specimen collected at the same locality although on a different date. These sequences were not included in the analyses because the vouchers could not be examined and their haplotype similarity would not have affected the outcome of the analyses.
Neighbour-joining analysis resulted in three distinct clusters that corresponded to the three species as defined here on the basis of morphology (Fig. 12a). Epimartyria pardella was the most distant species with mean distances of 4.52% and 5.09% from E. bimaculella and E. auricrinella, respectively. Morphologically it is the most distinct of the three species in genitalia. Epimartyria auricrinella and E. bimaculella seemed to be genetically closer to each other, with a mean distance of 2.57%. Morphologically, their genitalia are also more similar. Intraspecific sequence variation was small in E. bimaculella at 0.2% ± 0.1 and a minimum of three haplotypes could be distinguished. Two specimens with either short sequences or ambiguous sites were not assigned as haplotypes. In contrast, E. auricrinella showed a high amount of sequence divergence resulting in 7 subclusters representing different haplotypes. Pairwise divergence ranged from 0.16-2.69% (1.63% ± 0.832), with 9 out of 21 comparisons showing over 2% divergence (Table 1).
To assess whether the high amount of intraspecific divergence may be correlated with morphological variation, geography, or both, representatives of each haplotype were further subjected to a parsimony analysis. Maximum-parsimony analysis performed on unique haplotypes (7 for auricrinella, 3 for bimaculella, 1 for pardella) resulted in three most parsimonious trees, of which the strict consensus is illustrated (Fig. 12b). Of the 658 base pairs of the full barcode dataset, 607 were constant and 51 were variable, of which only 25 were parsimony-informative. The MP cladogram was similar to the NJ tree in that the three morphospecies were retained as separate, well-supported clades. Despite high sequence variation within the auricrinella clade, support for internal nodes was generally weak.
The haplotype network (Fig. 12c) resulted in a similar topology, with the three species separated from each other. In some cases, several haplotypes were present among specimens from the same locality (Fig. 32). For bimaculella, there were three haplotypes with 1-2 base pair differences from the type locality of Belcarra, BC, which were collected microsympatrically, two of which on the same date (Appendix 2). Similarly, for auricrinella, four haplotypes were present at Lac Brûlé, QC, of which three were 1-2 base pair apart but one (A5) was more than 10 bp divergent. At that locality haplotypes A1, A2 and A5 were present among specimens collected microsympatrically on the same date on two consecutive years (8 Jul 2002, 29 Jun 2003. Haplotype A4 from Tennessee, was closer to haplotypes A1-A3 from Lac Brûlé than to A5 from the same locality. The two localities are over 1300 km apart. Haplotypes A6 and A7 from Michigan were the most divergent, despite being geographically closer to Lac Brûlé than to Tennessee. The majority of barcode sequences came from a single locality for each of auricrinella and bimaculella. Thus it appears that higher haplotype diversity is associated with denser barcode sampling at single localities. Genitalia were examined in several specimens of auricrinella representing the different haplotypes (Appendix 2). This showed slight variation in the shape of the male valva, in which the inner margin varied from evenly rounded to medially angulate . Several specimens showed various intermediate states of this condition from having a barely suggested median angle to a sharp one. The angulation differed slightly between the two valvae on some specimens. Likewise slight variation was observed in the depth of the apical notch of the uncus, which was a little deeper or a little more sharply V-shaped in some whereas it was proportionally shallower and more obtusely V-shaped in others. The lateral dentation and recurved distal lobes of the gnathos also displayed minor variations. The variation observed in male genitalia was present across haplotypes from the same locality and seemed unrelated to geography. Males were predominant in all series examined, thus fewer females were compared. No detectable variation was observed in the latter.
Thus we consider the variation in both haplotypes and morphology to be intraspecific. Although a 2% minimal divergence threshold is commonly observed to separate species, and in particular Lepidoptera ), this rule of thumb is not universal and instances of high intraspecific divergence (Schmidt and Sperling 2008)  or shared haplotypes among closely related species (Lumley and Sperling 2010) are known. It has been hypothesized that geographical isolation is likely a major factor in the speciation and diversification of Micropterigidae due to their low vagility, narrow habitat requirement, and frequent allopatry (Imada et al. 2011). Further study involving much broader haplotype sampling of mtDNA and possibly nuclear genes will be required to elucidate the genetic structure of Epimartyria populations and whether cryptic species may be present.