Drosophila billheedi, Grimaldi, 2016

Grimaldi, David A., 2016, Revision of the Drosophila bromeliae Species Group (Diptera: Drosophilidae): Central American, Caribbean, and Andean Species, American Museum Novitates 2016 (3859), pp. 1-56 : 25-27

publication ID	https://doi.org/ 10.1206/3859.1
DOI	https://doi.org/10.5281/zenodo.5460915
persistent identifier	https://treatment.plazi.org/id/64000D25-E92A-FF82-FE6C-FC18FC99FA94
treatment provided by	Carolina
scientific name	Drosophila billheedi
status	sp. nov.

Treatment

Drosophila billheedi , new species

Figs. 2B View FIG , 12A–C View FIG

DIAGNOSIS: A larger-bodied species (thorax length 1.02 mm); dull, dark yellowish/light brown; facial carina very thin, head narrow relative to depth (head width index 1.01); prescutellar setae 0.40× length of post dorsocentrals, no smaller lateral pairs; most distinctive on basis of short, thick aedeagus, length 6.0× the greatest width, slightly curved in lateral view, aedeagal angle 106°; distiphallus short and broad in full ventral view, length 1.3× the greatest width; surstylus with 7 large, pointed prensisetae; hypandrium trapezoidal with slightly concave lateral margins.

DESCRIPTION: Male: Head. Frontal length 0.29 mm; frontal index 1.11, top to bottom width ratio 1.81. Front mostly dark ochre in color, ocellar triangle and fronto-orbital plates dull, frontal vitae finely striated and golden; ocellar triangle barely raised above front of head, slightly darker than rest of front. Orbital setae dark brown (not black), or1:or3 ratio 1.00, or2:or1 ratio 0.58, postocellar setae 0.51 and ocellar setae 0.68× the frontal length, postocellars crossing at tips; vt index 1.29. Vibrissal index 0.54. Face same color and texture as fronto-orbital plates. Carina narrow, thinner than basal antennomeres; edge flattened, without sulcus. Cheek index about 0.09. Eye index 1.58. Occiput slightly darker than front of head. Basal antennomeres same color as face; arista with 4 dorsal and 2 ventral branches, plus small terminal fork. Proboscis lighter than face, lateral surfaces of labellum slightly darker; palpus light, with one apical and one subapical seta.

Thorax length 1.02 mm. Scutum dull dark yellowish; 6 rows of acrostichal setulae. One large pair of prescutellar setae, 0.40× length of posterior dorsocentral setae; setae lateral to this barely larger than acrostichals; h index 0.83. Scutellum slightly lighter than scutum; basal scutellars slightly convergent; apical scutellars crossing; scut index 0.62. Pleura generally lighter than scutum, with small, slight infuscate areas near mesopleural suture, sterno index 0.74. Halter darker than pleura. Legs light, tan, without distinctive setation.

Wing hyaline, veins light brown, length 1.78 mm, length to width ratio 2.22. Indices: C, 2.38; ac, 2.31; hb, 0.47, 4-C, 1.00; 4V, 1.72; 5x, 1.73; M, 0.59, prox. Wing tip slightly pointed; vein R 2+3 straight (vs. slightly sinuous).

Abdomen color mostly dark yellowish, posterior margins of tergites with faint, diffuse light brown coloration.

Male terminalia (fig. 12A). Epandrium with dense microtrichia, ventral lobe only with setae; ventral lobe small, apically blunt, with 7–8 setae. Cerci fused laterally to epandrium. Surstylus virtually bare of microtrichia (with only 4–5 microtrichia); inner marginal row of 7 prensisetae pegs, pegs large and pointed; surstylus with about 11 ventral setae. Hypandrium trapezoidal, lateral margins slightly concave; greatest width equal to length, width of anterior margin 0.5× the length. Gonopods fused to hypandrium and aedeagal apodeme, with small, fine apical seta. Aedeagus fused to aedeagal apodeme; aedeagus short and thick, length 6.0× the greatest width, slightly curved in lateral view, aedeagal angle 106°; distiphallus broadly ovoid in full ventral view, with thick rim, length 1.3× the greatest width. Aedeagal apodeme keel shaped.

Female: Unknown.

TYPE: Holotype, ♂: “ TRINIDAD: Arima Valley / 107.12 [field notebook number]/ W.B. Heed, Dec. 1955.” Specimen is in good condition, point mounted, abdomen removed and cleared; genitalia dissected by D.A.G. (no. DBG 2), stored in glass microvial on same pin as specimen. In AMNH.

OTHER SPECIMENS: Known only from the holotype.

ETYMOLOGY: Patronym for the late William B. Heed, who collected this and many other Drosophila specimens throughout Central and South America in the 1950s and early 1960s.

COMMENTS: The aedeagus of this species is similar to that of D. aguape Val from southern Brazil, but differs by having a broader distiphallus and a surstylus with seven large prensisetae (vs. 8–9 smaller ones). It is also similar to D. mexiflora and D. sevensteri , n. spp., from Central America, by the short, thick, slightly arched aedeagus. It differs from those species by the thicker shaft (as seen in lateral view), the broader distiphallus, the very large prensisetae, and by the lateral margins of the hypandrium being slightly concave (vs. convex). From the field notes of W.B. Heed, for specimen 107.12 (holotype): “ 400 ft. elev—sweeping over grapefruits in nice wooded ravine—also some nutmeg trees and fruit.”