Bittacomorphella esakii Tokunaga 1938

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 : 45-47

Bittacomorphella esakii Tokunaga 1938

Bittacomorphella esakii Tokunaga, 1938: 189 –190 (original description)

Bittacomorphella esakii Tokunaga, Peus 1958: 42 (redescription, illustration)

Bittacomorphella esakii Tokunaga, Nakamura & Saigusa 2009: 278 –279 (redescription, illustration)

Diagnosis. Adult ( Figs. 7 f, 14). Legs with three white bands, broad proximal band around upper portion of tibia; middle band at proximal extremity of 1 st tarsomere ; distal band distal tip of 1st, 2nd, 3rd & 4th tarsomeres. Epandrium with prominent epiproct, epandrial lobes rounded.

Description. Larvae and pupae unknown. Adult. Measurements (n=2). Overall length 10.45mm (9.68– 11.16mm); head width (n=1) 0.75mm, height 0.72mm (0.71–0.73mm), length 0.43mm (0.40–0.46mm); antenna flagellum length 8.96mm; flagellomere proportions 1.00, 0.73, 0.96, 1.04, 1.04, 1.00, 0.93, 0.93, 0.89, 0.84, 0.76, 0.68, 0.68, 0.68, 0.60, 0.54, 0.50, 0.10; maxillary palpus length 1.34mm, segment proportions: 0.18, 1, 1.59, 1.22, 2.09; thorax length 1.48mm (1.43–1.53mm), height 1.37mm (1.29–1.45mm); wing length (n=1) 6.6mm, wing width (n=1) 1.36mm, R3+4+5 stem 0.39mm, R4+5 stem 1.53mm, R4 after fork 1.18mm, R5 after fork 1.05mm, R3+4+5:R4+5-stem:R4 1.00, 3.92, 2.52; r-m 0.27mm, M distal to r-m 2.56mm, Mdistal:R3+4+5 5.90, 1.00; R4:Mdistal 0.42, 1.00; CuA2 1.15mm; leg proportions, femur 1.0, 1.03, 1.15mm; tibia 0.98, 0.91, 1.07; tarsomeres, foreleg 0.70, 0.23, 0.15, 0.03, 0.04; midleg 0.64, 0.22, 0.14, 0.03, 0.04; hind leg 0.73, 0.25, 0.17, 0.03, 0.03; abdomen length: 8.84mm (8.16–9.53mm), male tergite proportions 1.00, 4.31, 2.01, 1.85, 1.66, 0.74, 0.22; male genitalia width 0.67mm, height: 0.78mm. Frons medial suture absent. Antennal scape with three setiform sensilla subdorsally along anterior margin; 18 flagellomeres. Face indistinct. Clypeus smaller than eye, margins straight, extending nearly antennal base, uninflated. Hypopharynx conical, directed ventrally. Labium prominent, elongate, extending well beyond clypeus. Labella fused medially, large and bean-shaped, forming pad. Antepronotum dorsal margin straight. Scutum glabrous, shining, sienna slightly lighter at medial apices of transverse suture; prescutal pit not prominent.No prescutellum evident. Scutellum light yellow, ovoid. Mediotergite light chocolate brown. Paratergite broad, semi-circular narrowing anteriorly. Anepisternal cleft heavily sclerotized, generally triangular narrowing to anterior point ventrally; anepisternal suture not evident. Metapleuron with very fine incomplete suture (almost unnoticeable in some individuals) emerging from medioposterior margin in straight line; setose prominence below halter. Pleurites color uniform from sienna to muddy yellow based. Wing membrane with single row of macrotrichia at extreme apex of cells R1, R3, R4; veins C to wing apex, Sc, R s, R1, R3, R4 & R5 after forking with macrotrichia; alula undeveloped. Posthalter weakly developed, broadly triangular, webbing to halter welldeveloped. Coxae yellow, femur yellow fading to overall leg coloration of brown. Three white bands, first on tibia near femoral joint, second on proximal end of 1 st tarsomere , third distal tip of 1st, 2nd & 3rd & 4th tarsomeres as well as acropod. Empodium unnotched. Abdomen as described for genus. Male. Epandrium bilobate, emarginate posterior margin, overall 2x wide vs long (from anterior margin to base of posteromedial stylus), internal folds above epandrial clasper absent; epandrial lobes semicircular, wider than long, shining, posterior margin straight, rounding at medial and lateral margins; lateral and medial corners rounded, with posteriomedial stylet at apex; epiproct prominent, dividing epandrial lobes medially, weak emargination posteriorly; hypoproct platelike, ovoid, located immediately underneath epiproct with several stout setae directed posteriorly. Epandrial claspers articulated at lateral extremity of epandrial lobe, directed medioventrally, tapering to acute glabrous point, curved hooklike medially. Subepandrial sclerite divided, articulated at mediobasal apex of epandrial clasper, broad ovoid plate directed medioanteriorly. Paramere glabrous, laterally compressed, weakly narrowed near midpoint, straight, apex subacutely triangular, curving dorsally. Gonocoxite conical, expanding to gonostylus, shorter than gonostylus.

Gonostylus rounded at tip, inner apex sensilla single row of 8 traversing from directly medial at posterior apex towards dorsal surface anteriorly. Gonopod closely associated with hypandrium. Basal division of hypandrium narrow band, with emargination and trough below gonocoxite; terminal division weakly articulated, pouchlike in shape, tapering to broad point. Superaedeagal membrane not inflated. Aedeagus with sperm sac as described for subfamily. Ejaculatory apodeme very large for Bittacomorphinae , tapering to pointed apex. Lateral ejaculatory process with broadly triangular, swept anterior laterally, lateral apices rounded, broad as 1/2 length of aedeagal sclerites, posterior margin with triangular tooth midway along length; ventral lobe heavily sclerotized on medial margin, posterior apex rounded, ridge traversing from posterior apex dorsolaterally to merge with lateral portion. Aedeagal sclerites broad, tapering toward apex; apical apodemes not readily distinguished in specimens examined. Subaedeagal sclerite heavily sclerotized, internal portion trapezoidal with posterior margin weakly emarginate, ventrolateral extremeties rounded, lateral margins convergent posteriorly constricting at junction with external section, ventral arm heavily sclerotized, earlike in shape; external section turnip-shaped, flattened, tip slightly curved dorsally. Female. Epigynium broadly semicircular, arched dorsally, fusion with epiproct very weakly evident as U-shaped change of color at posterior margin, lateral margins broadly rounded at base, straight distally, medial suture absent; posterior margin of epiproct convex. Cerci broad with base tapered slightly, dorsal margin weakly convex, apex obtusely rounded, ventral margin convex, inflated posteriorly. Apical nodule cylindrical with single elongate trichoid sensilla; cercus epigynium ratio 0.66, 1, cercus length to height 2, 1. Hypoproct and genital fork not visible on specimen examined. Hypogynium trapezoidal, hypogynial valve base distinct as straight sulcus across hypogynium, with square margins on either side of medial notch; medial notch small, narrow V-shaped, slitlike.

Material examined. JAPAN. ECHIGO. Mt. Amakazari, 25.vi.1935, coll. Baba [pinned 3 ♂, 2 ♀; slide 1 ♂; USNM]

Taxonomic Notes. Bittacomorphella esakii can be easily identified by the three white bands present on each leg, with the distal band including all of the tarsomeres.

Distribution. Fig. 20 a.

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 20. Asian Bittacomorphella distributions. a. Bl. thaiensis (star) and Bl. esakii (circle); b. Bl. nipponensis. Stars indicates type locality.