Plecia abruptavena Fitzgerald, 2021

Fitzgerald, Scott J., 2021, New species of Neotropical Plecia Wiedemann (Diptera: Bibionidae) and delineation of the americana-, nigra-, and xyele- species-groups, Zootaxa 5005 (1), pp. 21-40 : 22-25

Plecia abruptavena Fitzgerald sp. n.

( Figs. 1–5 )

Type Material. Holotype: Male , point-pinned ( USNM), “ COLOMBIA, Capueta, pass at Gabineta, 2 Sept. 1969, D.H. Messersmith ” [white label]. 11E [white label]. USNMENT 01556010 [white data matrix label] . HOLOTYPE, Plecia abruptavena Fitzgerald [red label], terminalia dissected.

Description. Holotype Male ( Fig. 1 ). General coloration. Entirely black. Thorax dark matte velvet black with abdomen slightly lighter blackish-dark brown. Legs slightly shiny black. Head. Three ocelli on tubercle. Antenna with eight black, bead-like flagellomeres with short dark setae, basal flagellomere about twice as long as broad, apical flagellomere round, minute. Compound eye holoptic with minute sparse ommatrichia, divided into upper and lower section of larger and smaller facets by slight depression. Face not produced anteriorly. Mouthparts not elongated, clypeus + proboscis shorter than antennae; clypeus rectangular, about twice as long as wide. Face, clypeus, and 5-segmented palps with short dark setae. Thorax. Mesonotum matte with a subtle median and a pair of more distinctive dorsocentral grooves. Mesonotum largely bare with short dark sparse setae in median and dorsocentral grooves as well as laterally. Thoracic pleurae bare except katepisternum with patch of dorsal setae and anepisternum with a few small dorsal setae. Legs. Missing middle legs. Remaining legs slender, long, with dense short dark setae. Hind femur only slightly clavate distally. Hind tibia slender, parallel-sided. Hind basitarsus slender, parallel-sided, approximately six times as long as wide. Wing ( Fig. 2 ). 9.5 mm, dark brownish fumose, darker anteriorly. Anterior veins dark brown, except basal half of M before r-m, remainder of M fork just beyond r-m, most of M 4, CuA, and CuP unpigmented (concolorous with wing membrane). A 1 dark brown, short, terminating even with crotch of anal lobe of wing. Pterostigma dark brown. R 2+3 short, curved (bent most strongly at midpoint), strongly divergent from R 4+5, ending in C. Halters blackish. Abdomen. With short dark hair. Terminalia ( Figs. 3–5 ). Epandrium (tergite nine) posteromedially with deep, broad, U-shaped cleft; bottom (anterior end of cleft) with a short, broad, shining, shelflike, posteroventrally-directed flap. Apex of epandrial lobes apically broadly rounded in dorsal view. Anterior edge of epandrium with a deep broad U-shaped cleft leaving most of the median area of epandrium (anterior to posteromedian cleft) membranous, so that sclerite is nearly divided medially. Gonocoxites ventrally continuous without a median projection, but with a pair of very small rounded setose submedian lobes forming part of the socket of the gonostyli (a small v-shaped notch present inbetween these two lobes but extending only about as deep as the bottom of the gonostylar socket). In ventral view, lateral lobes of gonocoxites taller than gonostyli, slender, with patch of dense setae on medial surface; lobes apically rounded in lateral view. In ventral view, gonostylus somewhat dagger-like, smooth, shinning, tapering apically, with a broad basolateral lobe bearing a patch of short minute hairs on outer edge. Gonostylus somewhat dorsoventrally flattened (best seen in dorsal view), but slightly tilted medially so that in posterolateral view the nearer gonostylus can be seen to be flat beyond the basolateral lobe while the farther gonostylus appears broad throughout (compare gonostyli in Fig. 5 ). In posterolateral view, very apex of gonostylus digitate and minutely hooked.

Female. Unknown.

Diagnosis & Remarks. This species is most similar to P. imperialis Schiner from Venezuela ( Hardy 1967), but is distinguished by the form of the gonostylus; in P. abruptavena the gonostylus has a basal lobe on the outer edge with the inner edge straight, whereas the gonostylus of P. imperialis is symmetrical; gonostylus bulbous at the base and distinctly constricted into the digitate apical portion ( Hardy 1945, fig. 145a). P. abruptavena is also similar to P. apoxys Fitzgerald from Peru ( Fitzgerald 1998), but can be distinguished by the shape of the gonostylus; dorsoventrally flattened, tapered to a digitate, slightly hooked apex in P. abruptavena and laterally compressed, more gradually and evenly hooking apically and with an acute apex in P. apoxys . P. abruptavena belongs to the nigra - species-group (see Discussion) and will key to couplet 24 in Hardy’s 1945 key.

Etymology. The specific epithet is from the Latin abruptus (broken off) and vena (vein) for the odd wing venation of this species which has portions of some veins which abruptly change from strong and distinctly pigmented to thin and hyaline.

Distribution. Known only from the holotype collected in Colombia.

Figures

FIGURES 1–2. P. abruptavena sp. n., holotype male. 1. Habitus. 2. Wing. Scale bars = ca. 1.0 mm.

FIGURES 3–5. P. abruptavena sp. n., holotype male, male terminalia. 3. Ventral (not dissected). 4. Dorsal (dissected). 5. Posterodorsal (not dissected). Scale bar = ca. 0.5 mm. Abbreviations: gc, gonocoxite; gs, gonostylus; llgc, lateral lobe of gonocoxite; t9, tergite nine.