Penthetria yakima Fitzgerald, 2021

Fitzgerald, Scott J., 2021, Penthetria Meigen (Diptera: Bibionidae): Revision of the New World species and world catalog, Zootaxa 4926 (4), pp. 451-500 : 482-484

Penthetria yakima Fitzgerald n. sp.

( Figs. 31 , 36–37, 39, 41, 56, Map 3 )

Type Material. Holotype: Male ( Fig. 31 ), point-pinned ( USNM), USA, Washington, N. Yakima, 25 September 1903, Eldred Jenne [white label] / A.L. Melander Collection, 1961 [white label] / USNMENT 01556096 [white barcode label] / HOLOTYPE, Penthetria yakima Fitzgerald [red label]; terminalia dissected, missing middle and right front legs. Paratypes: Same data as holotype except USNMENT 01556099 & 01556098 (2 males, USNM) .

Additional material examined: CANADA: “Can.,” Coquillett, 1M ( USNM); BRITISH COLUMBIA: Robson , 19 VIII 1957, H. R . Foxlee, 1M ( CNCI); 6 km E Salmon Arm, 7 IX 1989, A. Borkent, CD1071, 1M ( SFC); ONTARIO: Moose Factory , 11 IX 1949, J. R . Vockeroth, 1M ( CNCI); SASKATCHEWAN: Christopher L., 26 VIII 1948, A. R . Brooks, 1M, 1F ( CNCI) ; USA: WYOMING: Uinta Co., Bear River State Park , 13 Sept 1996, B.O. Huntsman, 1M ( BYUC), 1F ( SFC), C. Wallace, 1F ( BYUC) .

Description. Male ( Fig. 31 ). Body length: approx. [6.0] mm. Head. Black. Compound eye holoptic, covering virtually all of dorsal and lateral surface of head, with lateral longitudinal step dividing upper and lower portion of eye. Eyes nearly bare, with some very minute, very sparse ommatrichia present. Antennae dark brown to black, nine flagellomeres with black setae. Flagellomeres wider than long except first flagellomere more elongate, about twice as long as wide, and apical flagellomere which is slighter longer than wide and tapers to a rounded point. Three ocelli on well-developed tubercle. Thorax matte dark brown to black with light brown highlights on humeral ridge and posterior portions of pleurae. Thorax largely bare except fine short dark hairs on scutellum and in broad dorsocentral rows. Legs. Slender elongate. Entirely dark brown with dense short dark appressed hairs. Hind femur gradually slightly thickened (clavate) on apical half. Hind tibia slender elongate virtually parallel-sided. Hind basitarsus slender elongate to slightly robust, but not swollen, about five times as long as wide ( Fig. 31 ). Wings ( Fig. 31 ). 6.0–[6.5] mm (n=4), evenly brown fumose except slightly darker costally and cell sc which is slightly more pale. Veins dark brown, pterostigma brown, slightly contrasting to concolorous with membrane. Sc long, complete. R 2+3 elongate, subparallel to R 4+5, without basal appendix. CuA reaching wing edge, CuA and CuP parallel apically, not distinctly convergent or meeting. Abdomen. Dark brown with blackish areas. Terminalia (Figs. 36–37, 39, 41) dark brown to black. Tergite nine broader than long, posterior margin with v-shaped emargination on posterior edge that is about one-third to slightly over one-half the length of the tergite; lobes resulting from emargination broadly rounded posteriorly. In ventral view, posterior edge of medially fused gonocoxites + hypandrium with a pair of small, rounded, weakly to moderately projecting, ventromedian lobes, separated by a shallow, broad ventromedian cleft. In dorsal and ventral views, gonostylus elongate, relatively narrow, gently curved, apically minutely truncate or with small notch (Figs. 36–37). In posterior view, gonostylus relatively slender, tapering apically ( Fig. 41 ). In dorsal and ventral views fused parameres (dorsal sclerite) typically projecting slightly beyond genital capsule, shiny, brown, heavily-sclerotized, dome-like, roughly diamond-shaped (broadest medially), apically coming to a broadly rounded point, without divergent horn-like lobes apically ( Fig. 39 ). Cerci fleshy, apically rounded with setae.

Female. Similar to male. Body about 5.0 mm and wing 6.0 mm (n=1). Eyes dichoptic. Antennae with 7–8 flagellomeres (apically flagellomeres somewhat fused and difficult to enumerate). Female hind basitarsus slender elongate. Abdomen stout. Terminalia ( Fig. 56 ): Tergite nine present dorsally as a very narrow transverse strap medially subdivided; tergite more produced ventrolaterally. Tergite ten minute, longitudinally elongate. Cerci two-segmented, ultimate segment relatively short. Subgenital plate (= sternite eight) large, longitudinally subdivided, posterior margin with a pair of broad lobes medially.Y-shaped genital fork present. Sternite 10 broadly rounded posteriorly. Three rounded, sclerotized, capsule-like, spermathecae present.

Diagnosis. Males of P. yakima can be distinguished from all New World congeners by the following combination of characters: gonostylus relatively slender, apically truncate and sometimes notched (Figs. 36–37, 39, 41), paramere diamond-shaped ( Fig. 39 ), tergite nine posteromedially cleft about one-third to slightly over one-half its length, without shelf-like development or a field of densely-set, short, black, spine-like setae, and ventromedian lobes of gonocoxites weakly to moderately developed.

Remarks. Males of P. yakima are most similar to P. heteroptera , but can be differentiated by the narrower gonostylus and more diamond-shaped paramere (compare Figs. 38–41 ).

Females of P. yakima ( Fig. 56 ) are indistinguishable from females of P. heteroptera and P. arizonensis . However, unassociated females from the northwestern USA (west of the Rocky Mountains) likely belong to this species as it is the only species currently recorded from this area.

Etymology. The specific epithet yakima is based on the name of the type locality “N. Yakima,” Washington.

Geographic & Seasonal Distribution. Northwestern USA (Washington & southwestern Wyoming) and British Columbia east to Ontario in Canada ( Map 3 ). Based on current distribution records, P. yakima and the similar P. heteroptera are allopatric in the USA and sympatric across most of Canada. The P. yakima specimens known from western Wyoming, USA occur at the southwestern edge of the Wyoming Basin which is essentially high desert habitat along the Bear River in the low areas between the Wyoming Range to the North and the Uinta Mountains of Utah to the South; this is the farthest eastern and southern record for this species in the USA. P. yakima has been recorded in August and September ( Table 1).

Figures

MAP 3. Distribution of P. heteroptera (black circle) and P. yakima (star).

FIGURES 30–32. Holotype males, lateral. 30. P. neonigrita n. sp.. 31. P. yakima n. sp.. 32. P. arizonensis n. sp.. Scale bars = ca. 1.0 mm. Abbreviations: hb, hind basitarsus.

FIGURES 38–41. Male terminalia. 38. P. heteroptera, dorsal, tergite nine removed, topotypic (Maryland, USA). 39. P. yakima n. sp., holotype, dorsal, tergite nine removed. 40. P. heteroptera, posterior, topotypic (Maryland, USA). 41. P. yakima n. sp., holotype, posterior. Scale bar = ca. 0.5 mm.Abbreviations: c, cerci; ea, ejaculatory apodeme; ga, gonocoxal apodeme; gc, gonocoxite; gs, gonostylus; p, paramere; t9, tergite nine.

FIGURES 54–57. Female terminalia and eggs. 54–56. Female terminalia. 54. P. neonigrita n. sp., dorsal. 55. P. neonigrita n. sp., ventral. 56. P. yakima n. sp., ventral. 57. P. heteroptera, eggs (dissected from abdomen). Scale bars = ca. 0.25 mm. Abbreviations: c1, cercus 1; c2, cercus 2; s7, sternite seven; s8, sternite eight; s10, sternite ten; sp, spermatheca; t7, tergite seven; t8, tergite eight; t9, tergite nine.