Drosophila (Sophophora) olmeca, Grimaldi, 2024

Grimaldi, David A., 2024, The Drosophila (Sophophora) obscura species group in the Americas (Diptera: Drosophilidae): review, revisions, and three new species, American Museum Novitates 2024 (4015), pp. 1-44 : 30-32

Drosophila (Sophophora) olmeca , new species

Figures 5D , 9K ; 12C, D ; 15B, E

DIAGNOSIS: Facial carina very thin, small; acrostichal setae in 6 rows; sex comb with 4 teeth on ta1, 1 on ta2. Known only from male. Like D. narragansett , male with silvery frons and relatively small body size (0.74 for D. olmeca type, mean of 0.88 mm thorax length for narragansett ), D. olmeca distinguished by the distinctively longer outer lobes of ventral epandrial lobe, whose tips nearly touch ventrally; postgonites shorter, length 0.60× that of hypandrium (vs. 0.77–0.80× in D. narragansett ). Further distinguished from D. narragansett by several wing indices, as given in the description below.

DESCRIPTION: Coloration (♂ only): Frons with silvery pollinosity over entire front, including frontal vittae, fronto-orbital plates, and ocellar triangle (most obvious in frontal view, in dorsal view frontal vittae are darker); antennae, face, ventral margin of cheek light brown (cheek dorsally lighter); clypeus and palps light brown. Scutum and scutellum medium brown, dull, with dusting of pruinescence; postpronotal lobe, notopleural area, anepisternum similarly brown; katepisternum lighter. Legs light yellow; halter knob light brown; abdomen uniformly brown in ♂.

Head: Arista with 4 dorsal, 2 ventral branches, plus terminal fork; pedicel with 3 longer setae. HD/HW 0.80. Anterior reclinate orbital seta slightly posterolateral to proclinate orbital; posterior reclinate slightly closer to proclinate than to inner vertical setae; proclinate 1.7× length of anterior reclinate, posterior reclinate 1.07× length of anterior reclinate. Ipsilateral vertical setae close; inner vertical in line with proclinate and posterior reclinate, IV/OV 0.95. Ocellar setae sockets on tangent between median and posterolateral ocelli; postocellars of moderate length, shorter than ocellars, OC/POC 1.33, parallel, pointing backward; 4 small setulae in ocellar triangle. Frons with 5 setulae near anterior margin. FL/LFW 1.00, UFW/LFW 1.50. Face relatively short, FD/FW 1.15, frontal W-index 2.95; facial carina very narrow, short (0.3× length of face); vibrissa well developed, 1st genal seta small, GS1/VL 0.38, gena with ~6 rather short setae. Cheek of moderate depth, ED/CD 8.2. Palp with 1 long apical seta. Eye broadly oval in lateral view, EW/ED 0.75.

Thorax: Length 0.74 mm. Acrostichals in 6 even rows between anterior dorsocentrals, lengths slightly increasing posteriad; acrostichals in front of scutellum or anterior dorsocentrals not enlarged. Anterior dorsocentrals 0.67× length of posterior ones; distance between ipsilateral dorsocentrals less than that between contralateral ones. Postpronotum with 2 strong setae, UPS/LHS 0.77; 2 strong notopleural setae near notopleural suture, plus longer seta dorsally, another, long postsutural seta; katepisternum with 2 large setae, posterior one nearly 2× the length (S-index 0.57), sclerite with 4–5 small setulae. All scutellar setae parallel, posterior scutellars longer, ASC/PSC 0.82. Legs: profemur with short, ventral row of 3 setae (lengths slightly less than femur width); mid and hind tibiae with stout, ventroapical setae, thinner dorsal-preapical seta; lengths of ♂ protarsus ta1 and ta2 nearly equal; ta1 with 4 teeth, ta2 with 1; ta1 teeth touching, greatest length of teeth 1.3× the width of tarsomere. Wing: C-index 2.44 (vs. 2.65 in D. narragansett ), hb-index 2.86 (vs. 2.49), 4V-index 2.23, 5X-index 2.50 (vs. 2.15).

Abdomen: Male terminalia: epandrium slightly higher than wide; cerci relatively flat, without distinct ventral lobe, ventrally with tuft of ~8 setulae; outer lobe of ventral epandrial lobe long, curved inward such that distal tips almost touch; margin of inner lobe of ventral epandrial lobe hardly defined from surstylus, base of inner lobe with fine furrows; surstylus with row of 7–8 prensisetae; aedeagus and valves only slightly shorter than postgonites; [presence of microtrichia on aedeagus not observable]; aedeagal valves without micropapillae. hypandrium length 1.45× the width. Female terminalia: unknown.

TYPE: Holotype ♂: San Cristobal, Chiap [as], MEX [ICO] / May 1959, M. Wasserman. Dissected ( ASG25 ), in AMNH.

ETYMOLOGY: Derived from the Olmec people, who lived 1200–400 BCE in southeastern Mexico and are well known for their carvings of monumental stone heads.

SPECIMENS EXAMINED: Known only from the type specimen.

DISTRIBUTION: Chiapas, Mexico.

Figures

FIG. 5. Frontal view of heads of Drosophila narragansett (including seminole, new synonym) and the related species D. olmeca, n. sp. A. D. narragansett, female paralectotype (ASG 11); B. D. narragansett, male paralectotype (ASG 10); C. D. seminole, male holotype; D. D. olmeca, n. sp., male holotype (ASG 25).

FIG. 9. Protarsal male sex combs (tarsomeres ta1 and ta2, and ta3 for D. chibcha from Peru) of species in the affinis subgroup. A. D. affinis (ASG 29); B. D. algonquin (ASG 32); C. D. athabasca (ASG 31); D. D. azteca (ASG 13: San Franciso, CA); E. D. azteca (ASG 06: Leticia, Colombia); F. D. chibcha, n. sp. (ASG 04: Zurqui, Costa Rica); G. D. chibcha, n. sp. (ASG 05: Las Alturas, Costa Rica); H. D. chibcha (ASG 07: Rancho Grande, Venezuela); I. D. chibcha (ASG 08: Wayqecha, Peru); J. D. narragansett (ASG 10); K. D. olmeca (ASG 25); L. D. tolteca (ASG 23). All to the same scale.

FIG. 12. Epandria and associated structures in representative species of the affinis subgroup. A. D. narragansett (ASG 10); B. Details of A; C. D. olmeca, n. sp. (ASG 25); D. Detail of C; E. D. tolteca (ASG 23).

FIG. 15. Hypandrium, aedeagus and other appendages of representative species of the affinis subgroup (ventral views). A. D. narragansett (ASG 10: paralectotype, Massachusetts); B. D. olmeca (ASG 25: holotype); C. D. tolteca (ASG 23); D. D. narragansett (ASG: Virginia); E. D. olmeca (ASG 25: holotype, detail of B). A–C to same scale; D and E to same scale