Bittacomorphella furcata Fasbender & Courtney, 2017

Fasbender, Andrew & Courtney, Gregory W., 2017, A revision of Bittacomorphinae with a review of the monophyly of extant subfamilies of Ptychopteridae (Diptera), Zootaxa 4309 (1), pp. 1-69 : 38-40

Bittacomorphella furcata Fasbender & Courtney sp. nov.

Diagnosis. Adult ( Figs. 7 e, 11). Legs with white confined to distal part of 1st, 2nd & 3rd tarsomeres, 4&5th tarsomeres pale brown. Epandrium subquadrate, platelike, posteriorly emarginate; gonostylus subequal in length to gonocoxite, curved dorsally; basal apical sclerite platelike; parameres bifurcate, medial section convergent.

Description. Larvae and pupae unknown. Adult. Measurements (n=2). Overall length 10.82mm (10.51– 11.16mm); head width 0.90mm (0.84–0.97mm), height: 0.88mm (0.88– 0.88mm), length 0.50mm (0.44–0.55mm); antenna flagellum length 6.7mm, flagellomere proportions 1.00, 0.72, 0.88, 1.06, 1.02, 1.02, 1.06, 1.02, 1.00, 0.83, 0.81, 0.76, 0.67, 0.67, 0.67, 0.60, 0.58, 0.53, 0.46, 0.14; maxillary palpus length 1.57mm, palpus segment proportions 1, 1.27, 1.33, 1.15; thorax length 1.62mm (1.55–1.68mm), height 1.58mm (1.56–1.60mm); wing length 8.25mm (8.00– 8.50mm), width 1.88mm (1.88– 1.88mm); R3+4+5 stem 0.60mm, R4+5 stem 2.00mm, R4 after fork 1.70mm, R5 after fork 1.05mm; R3+4+5:R4+5-stem:R4 1.00, 3.33, 2.83, r-m 0.30mm, M distal to r-m 3.25mm, Mdistal:R3+4+5 5.41, 1.00; R4:Mdistal 0.52, 1.00; CuA2 1.57mm; leg proportions: femur 1.0, 1.01, 1.09mm; tibia 0.96, 0.96, 1.17; tarsomeres, foreleg 0.6, 0.19, 0.12, 0.04, 0.04, midleg 0.51, 0.17, 0.13, 0.04, 0.04, hind leg 0.56, 0.20, 0.13, 0.04, 0.04; abdomen length: 10.13mm, male tergite proportions 1.00: 4.11, 2.55, 2.05, 1.88, 0.65, 0.40; male genitalia width: 0.63mm, height 0.69mm. Frons with medial suture indistinct, most prominent between antennal bases; triangular field of trichoid sensilla emerging from anterior occipital margin, expanding posteriorly. Antennal scape with four regularly spaced setiform sensilla in transverse line midway along anterior surface; pedicel with single equatorial line of trichoid sensilla; 20 flagellomeres. Face incised by clypeus nearly to dorsal margin. Labrum subconical triangular, directed anteroventrally. Labium extending beyond clypeus. Labella elongate elliptical shape, yellow, anterolateral margins with elongate sensilla, not fused medially. Antepronotum trapezoidal, two small setose lobes extend anterior at dorsolateral apices. Scutum glabrous, pollinose, fuscous with lateral margins and sutures straw yellow. Scutellum ovoid muddy yellow; prescutellum absent. Mediotergite ruddy brown. Paratergite indistinct, narrow, scythe-like. Anepisternal cleft subquadrate, lightly sclerotized; anepisternal suture indistinct, incomplete, reaching neither anterior nor posterior margin. Metapleural suture running indistinctly to level of base of abdomen, distinct in a broad arc to halter. Pleurites ruddy brown. Wing membrane with scattered macrotrichia on distal 1/ 4 in cells Sc, R1+2, R3, R4, R5, macrotrichia apically in cell M; veins with macrotrichia C to wing apex, Sc, R1, R3, and R4 & R5 after forking; alula undeveloped. Posthalter moderately developed, triangular, with several long translucent sensilla apically, largely free of webbing posteriorly. Coxae yellow; femur straw yellow apically, becoming light brown at joint with tibia, tibia pale yellow basally becoming light brown distally, tarsomeres with white confined to distal tip of 1st, and complete 2nd & 3rd tarsomeres, base of 1 st tarsomere dull brown and 4th & 5th tarsomeres yellow-brown. Empodium notched proximally. Abdomen dark olive to fuscous, posterior margins of tergites with narrow dull straw yellow band, tergite VII completely straw yellow. Male. Epandrium about 1.25x as wide as long; heavily convex dorsally, emarginate across entire posterior margin, posteromedial stylus obtuse subconical lobe dorsomedial to epandrial clasper, internal suture extending posteromedially from lateral margin of posteromedial style; epiproct not readily apparent, hypoproct ovoid sclerotized plate. Epandrial clasper dorsal surface bulging, abruptly tapering to sub-acute point, apex curved anterodorsally, dorsal and medial surfaces with long setae. Parameres bifurcate at 1/3 of total length; lateral branch shorter, straight, gradually tapering to subacute point; medial branch laterally compressed, nearly ribbon-like, basal portion directed posteromedially, rising dorsally, distal portion parallel, tapering to subacute point. Gonocoxite conical, expanding to gonostylus. Gonostylus sub-equal to gonocoxite, expanded at base, curving dorsally at expanded apex, inner apex sensilla single row of 8–9 along dorsomedial margin, arcing around margin at apex. Basal division of hypandrium posterior margin emarginate at terminal division, joint broadly membranous. Terminal division articulated, sides parallel, cupped dorsally forming pouch, obtusely rounded apex invaginated; lateral surfaces heavily provided with setae. Sperm sac with ovoid windows posteroventrally. Lateral ejaculatory processes wing-like, weakly curved anteriorly towards apex, laterally compressed and angled anteromedially, ventral margin heavily sclerotized, lateral apex trapezoidal with rounded margins; ventral lobe process small, rounded, directed posteriorly; anterior protrusion bar-like, straight sided, apex recurved laterally to nearly a semicircle, extending into sperm sac. Ejaculatory apodeme teardrop shaped, expanding to rounded apex. Sclerites of aedeagus narrowly sclerotized, not tapered. Apical apodemes simple, upper lobe reduced, ventral lobe square, flaglike, apex broad; lateral apodemes absent. Subaedeagal sclerite poorly developed, association with ventral apical apodeme reduced, ventral arms form trapezoidal plate over posterior surface of apex of aedeagus. Female. Epigynium trapezoidal, flat dorsally, posterior margin straight, lateral margins straight, posterior margin indistinct, medial suture indistinct. Cerci with base indistinct, dorsal margin weakly convex, apex broadly rounded, ventral margin slightly convex, with an even arc. Hypoproct not visible on specimen examined Apex of cercus with short, cylindrical nodule with single elongate trichoid sensilla medially; cercus epigynium ratio 0.76, 1. Genital fork not visible on specimen examined. Hypogynium quadrate, hypogynial lobes indistinct, lateral margins formed into lateroposterior triangular lobes, constricted medially, medial notch incising hypogynium 1/3rd of length.

Material examined. Holotype. UNITED STATES. OREGON . Benton Co. 4 mi. up Woods Crk. Rd. jct. Hwy 20; sweep banks of Woods Creek , 9.v.2013, coll. S. Fitzgerald [pinned 1 ♂; USNM]; Paratypes: Same as holotype [pinned 1♂; 1♂ 2.v.2013; PNDL]; WASHINGTON . Mason Co. Lake Cushman, 27.vi.1917, coll. H.G. Dyar [pinned 2 ♂, 1 ♀; USNM]

Etymology. The specific epithet refers to the distinctive bifurcate structure of the paramere as viewed dorsally.

Taxonomic notes. Bittacomorphella furcata can be separated from the remaining Bl. sackenii group by the lack of pollinosity of the scutum, as well as the furcate paramere and reduced subaedeagal sclerite of the aedeagus in the male genitalia.

Distribution. Fig. 19 b.

Figures

FIGURE 7. Bittacomorphine male wings. a. Bittacomorpha clavipes; b. Bi. occidentalis; c. Bittacomorphella pacifica Alexander; d. Bl. sackenii Von Röder; e. Bl. furcata sp. nov.; f. Bl. esakii Tokunaga; g. Bl. fenderiana; h. Bl. jonesi Johnson; i. Bl. nipponensis Alexander; d. Bittacomorphella thaiensis Alexander. All scale bars 1 mm except “ b ” (2 mm).

FIGURE 19. Nearctic Bittacomorphella distributions. a. Bl. pacifica; b. Bl. furcata (star & square) and Bl. sackenii (circles); c. Bl. fenderiana; d. Bl. jonesi. Stars indicates type locality.