Tachytrechus alatus
Creators: name: Brooks, Scott E.
name: Cumming, Jeffrey M.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Dolichopodidae
Tachytrechus
Tachytrechus alatus

description: Key to species of the Tachytrechus alatus species group
1. Two notopleural bristles, posterior bristle sometimes very reduced ........................................................... 2
- One notopleural bristle ............................................................................................................................... 4
2. Palpus with large, stout seta on lower margin (Fig. 8A); face and upper third of clypeus metallic greenishcoppery, abruptly pale yellow on lower part of clypeus; mid tarsus with tarsomere 2 subequal or shorter than basitarsus. Male: clypeus with strong medial carina, lower margin truncate (Fig. 8A); wing with two adjacent costal swellings (Fig. 8B); hypandrium lacking elongate ventral projection and subapical process (Figs. 9 C, 9D) (southern Mexico and Guatemala, Fig. 12) .................................. transversus (Van Duzee)
- Palpus lacking large, stout seta on lower margin (Figs. 3A, 3B, 10A); face and clypeus not as above; mid tarsus with tarsomere 2 longer than basitarsus. Male: clypeus lacking medial carina, lower margin rounded (Figs. 3A, 10A); wing without costal swelling (Figs. 3C, 10B); hypandrium with elongate ventral projection and lamellate subapical process on right side (Figs. 4 A, 4B, 11A, 11B) ................................... 3
3. M with distinct S-shaped bend; R4+5 and M subparallel in distal portion (Figs. 3C, 3D); tibiae and tarsi
mainly dark; upper part of face metallic greenish or bluish, lower part of face and clypeus silvery. Male: wing membrane unevenly infuscated (Fig. 3C); fore tibia mainly dark, apex slightly swollen with silvery anterodorsal patch; male fore tarsomeres 2 and 3 enlarged with anterior surface bare and silvery (Fig. 3E) (northern Costa Rica, Fig. 12) ...................................................................... costaricensis Brooks sp. nov. - M with weak sinuous bend; R4+5 and M slightly converging distally (Fig. 10B); tibiae and basal part of tarsi pale; face and clypeus brownish. Male: wing membrane evenly infuscated (Fig. 10B); fore tibia pale, apex unmodified; fore tarsomeres 2 and 3 not as above, tarsomere 2 with anterodorsal row of long curved hairs (Fig. 10D) (southern Costa Rica, Fig. 12) ................................................. zumbadoi Brooks sp. nov.
4. M with two 90° bends (Figs. 1A, 1B); R2+3 of male very short, ending at costa before midpoint of wing; crossvein dm-cu of male close to wing base, well before midpoint of wing (Fig. 1A); crossvein dm-cu of female just before midpoint of wing, slightly shorter than distal part of CuA1 (Fig. 1B); right basiventral epandrial lobe with prominent basal projection; hypandrium with a pair of sickle-shaped projections on right margin just beyond middle (Fig. 1C) (Peru, Fig. 13) ................................................. alatus (Becker)
- Bends in M obtuse; R2+3 of male ending at costa well beyond midpoint of wing; crossvein dm-cu at or slightly beyond midpoint of wing in both sexes, longer than distal part of CuA1 (Figs. 2A, 5A, 6A, 6B, 7A, 7B); right basiventral epandrial lobe lacking prominent basal projection; hypandrium either lacking pair of sickle-shaped projections on right margin (Figs. 2B, 6D, 7C), or with single elongate sickle-like projection near middle and lamellate subapical process both on right side (Figs. 5C, 5E)........................ 5
5. M with weak sinuous bend; R4+5 and M convergent distally (Figs. 6A, 6B); hind femur dark metallic green; larger flies (body length 7.9–8.5 mm, wing length 10–11 mm). Male: wing with elongate costal swelling (Fig. 6A); clypeus parallel sided and truncate below (Fig. 6C); hind femur with 2–3 preapical bristles; right and left basiventral epandrial lobes greatly elongated, symmetrical, curved and tapered distally; apicoventral epandrial lobe short, projected posteriorly (Fig. 6E); cercus round (Colombia, Fig. 13) ........................................................................................................................................ giganteus (Brooks)
- M with pronounced S-shaped bend; R4+5 and M subparallel distally (Figs. 2A, 5A, 7A, 7B); hind femur mainly or entirely pale; smaller flies (body length 5.0– 5.7 mm, wing length 5.1–5.8 mm). Male: wing lacking costal swelling; clypeus rounded below; hind femur with 1 preapical bristle; right and left basiventral epandrial lobes relatively short, asymmetrical with right lobe more developed; apicoventral epandrial lobe elongate, projected ventrally (Figs. 2C, 5C, 5D, 7D); cercus subrectangular (Fig. 5D) ..... 6
6. Male fore tarsus with tarsomeres 4 and 5 enlarged (Fig. 5B); hypandrium with lamellate process subapically on right side, with lamellate process along left lateral margin, and with elongate sickle-like projection near middle on right side (Figs. 5C, 5E) (Peru, Fig. 13) ...................................... dios Brooks sp. nov.
- Male fore tarsus with tarsomeres 4 and 5 not enlarged; hypandrium not as above, simple, at most with weak dentiform projection on right margin (Figs. 2B, 7C) ......................................................................... 7
7. Face mainly metallic green. Male: basitarsus of foreleg with weak silvery reflections anteriorly, basitarsus and tarsomere 2 with curved setae ventrally; M and CuA1 not thickened basally (Fig. 2A); apicoventral epandrial lobe extremely well-developed with pointed apex, medial seta positioned near base, lateral seta near middle (Fig. 2C); hypandrium wide, right margin with dentiform projection (Fig. 2B) (Colombia, Fig. 13)................................................................................................................................... analis (Parent)
- Face mainly brownish with weak silvery-green reflections. Male: fore tarsus distinctly silvery anteriorly, basitarsus lacking curved ventral setae; M and CuA1 thickened in basal section (Fig. 7A); apicoventral epandrial lobe with blunt apex bearing medial and outer setae (Fig. 7D); hypandrium narrow, right margin lacking projection (Fig. 7C) (Peru, Fig. 13) ........................................................... peruicus Yang & Zhang
description: Published as part of Brooks, Scott E. & Cumming, Jeffrey M., 2008, The Tachytrechus alatus species group (= Syntomoneurum Becker) revisited: new species and revised species group limits (Diptera: Dolichopodidae), pp. 1-27 in Zootaxa 1676 on pages 3-4, DOI: 10.5281/zenodo.180314