Gymnoclasiopa chiapas (Mathis) Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012, A revision of the New World species of Gymnoclasiopa Hendel (Diptera, Ephydridae), ZooKeys 248, pp. 1-69 : 23-25

Gymnoclasiopa chiapas (Mathis) comb. n. Figs 25-28

Ditrichophora chiapas Mathis 1997: 702.

Diagnosis.

This species is distinguished from congeners by the following combination of characters: Moderately small shore flies, body length 2.00-2.65 mm; generally shiny black. Head: Frons of male and female similar, moderately microtomentose on posterior portion, although bare at bases of setulae and small area just laterad of posterior ocelli, anterior third of frons bare, shiny, with 2 lunate indentations, medial area with pointed extension of moderately microtomentum from posterior portion; 1 proclinate, fronto-orbital seta, inserted just behind and laterad of reclinate seta. Antenna black; apical margin of pedicel and basal flagellomere invested with whitish gray microtomentum; arista bearing 5 dorsal rays. Face bearing 3 lateral, facial setae, dorsal seta longest, inserted at level of facial prominence, ventral setae progressively shorter, evenly spaced with distance between less than width of 1st flagellomere; face mostly black, shiny, but with pattern of silvery white microtomentose, vertical stripes; lateral facial stripe immediately adjacent to parafacial, other vertical stripe just laterad of midfacial vertical bare area; also silvery white microtomentose on dorsal portion of antennal grooves and along ventral, facial margin; parafacial bare, shiny black; gena-to-eye ratio 0.10-0.12. Mouthparts, including maxillary palpus, black. Thorax: Mesonotum generally sparsely microtomentose, golden brown, becoming bare laterally through supra-alar area and continuing ventral through pleural area; prescutellar acrostichal setae well developed. Wing hyaline; costal ratio 0.40-0.43; M vein ratio 0.70-0.73; halter stem blackish brown; knob yellowish to whitish. Legs except tarsi black, mostly shiny, femora with some surfaces very sparsely microtomentose; tarsi yellow except apical 1-2 brown; forefemur with row of numerous, very short, peglike setulae along posteroventral surface. Abdomen: Tergites black, generally shiny, especially laterally and ventrally. Male terminalia (Figs 25-27): Epandrium in posterior view (Fig. 25) moderately broadly as an inverted, robust U, dorsal portion nearly straight, narrower than lateral arms, ventral margins of arms slightly expanded, broadly rounded, in lateral view wider ventrally; cercus in posterior view (Fig. 25) semilunate, elongate, narrow, shallowly arched, parallel sided; aedeagus in lateral view (Fig. 27) slipper-like, base deeply and unevenly incised, tapered toward apex, apex moderately narrowly rounded, in ventral view (Fig. 26) broadly tapered on basal third, basal margin almost truncate, very shallowly arched, with thin, wing-like, narrow projections sub-basally, apical margin twice as broad as basal margin, shallowly crenulate; phallapodeme in lateral view (Fig. 27) more or less triangular, in ventral view (Fig. 26) as an inverted T; ejaculatory apodeme in lateral view (Fig. 27) obtusely L-shaped, tapered from wider apex to narrow base; postgonite in lateral view (Fig. 27) as a parallelogram, acutely narrow basally and apically, each lateral margin obtusely angulate, bearing 2 setulae along basoposterior margin and 1 setula along margin toward hypandrium; pregonite in lateral view (Fig. 27) moderately elongate, tapered, narrowed toward hypandrium, flared toward aedeagus, aedeagal end truncate, in ventral view shallowly arched medially, thereafter laterally slightly tapered, lateral margin rounded; hypandrium in ventral view (Fig. 26) broadly and shallowly rounded along anterior margin, in lateral view (Fig. 27) arched, posterior portion digitiform, thereafter anteriorly becoming wider, dish-like.

Type material.

The holotype male of Ditrichophora chiapas Mathis is labeled "MEXICO. Chiapas: El Triunfo (49 km S Jaltenango) 14 May 1985, 1800 m[,] Wayne N. Mathis/HOLOTYPE Ditrichophora chiapas W.N.Mathis USNM [red; species name handwritten]." The holotype is double mounted (minuten pin in block of plastic), is in excellent condition, and is in the USNM. The allotype female and four paratypes (4♂; USNM) bear the same locality label as the holotype. Other paratypes are as follows: MEXICO. Chiapas: El Triunfo (49 km S Jaltenango; 1300-2000 m), 13-15 May 1985, W. N. Mathis (3♂; UNAM, USNM).

Type locality.

Mexico. Chiapas. Biosfera El Triunfo (ca 49 km S Jaltenango; 15°39.5'N, 92°48.5'W; 1800 m).

Distribution

(Fig. 28). Neotropical: Mexico (Chiapas).

Remarks.

El Triunfo is a site in the cloud forest of southern Mexico (some of the only cloud forest that remains largely undisturbed in Mexico).

Based on external characters, this species was placed initially in the genus Ditrichophora , but structures of the male terminalia indicate a closer association with Gymnoclasiopa .

This species is distinguished from congeners, especially Ditrichophora bella , by the following combination of characters: Postpronotum and notopleuron of males are generally bare of microtomentum and shiny, similar to the mesonotum and anepisternum; the prescutellar acrostichal setae are well developed; males have the anterior third of the frons bare of microtomentum, shiny black; halteres are white; there is only one proclinate fronto-orbital seta; and by the pattern of silvery white microtomentum on face (see species description).