Discocerina ceraceps (Cresson) Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2013

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2013, A revision of the shore-fly genus Hydrochasma Hendel (Diptera, Ephydridae), ZooKeys 363, pp. 1-161 : 109-110

Discocerina ceraceps (Cresson) comb. n. Figs 200-203

Hecamedoides ceraceps Cresson, 1938: 27 [ “Brazil”; HT ♂, ANSP (6534)].

Hydrochasma ceraceps . Cresson 1946: 141 [generic combination]. Wirth 1968: 8 [Neotropical catalog]. Mathis and Zatwarnicki 1995: 182 [world catalog].

Diagnosis.

This species is distinguished from congeners by the following combination of characters: Generally densely microtomentose, whitish gray to blackish gray. Moderately small shore flies, body length 2.55 mm. Head: Frons mostly yellow, ocellar triangle gray; area immediately laterad of ocellar triangle brownish yellow; fronto-orbits whitish gray; pseudopostocellar setae well developed, length subequal to proclinate fronto-orbital seta. Antenna yellow; arista bearing 5-6 dorsally branching rays. Face mostly faintly yellow, becoming more whitish yellow ventrally and on dorsal portion of antennal grooves; bearing 3 larger setae in vertical row and with a small seta at ventral extent of row. Eye ratio 0.80. Gena high, mostly silvery white, gena-to-eye ratio 0.35. Thorax: Mesonotum mostly faintly grayish tan, becoming grayer laterally; pleural areas gray. Wing ratio 0.42; costal vein ratio 0.41; M vein ratio 0.54. Femora gray with extreme apex yellowish, medial surface of hindfemur shiny, reddish yellow; tibiae mostly yellowish with some sparse whitish to whitish gray microtomentum, especially hindtibia medially; tarsi yellow. Abdomen: Tergites 2-4 with wide medial stripe bronzish brown, gray laterally; tergite 5 mostly gray, truncate apically, bearing 4 larger apical setulae, length of larger setulae equal to width of tergite at apex. Male terminalia (Figs 200-203): Epandrium in posterior view (Fig. 200) more or less cordate, wide on dorsal half, tapered ventrally to a narrow, truncate ventral apex, dorsal margin broadly connected, width of dorsal connection in lateral view equal to width of a cercus, epandrium in lateral view (Fig. 201) becoming widest at midheight, thereafter tapered to point ventrally; cercus semi-hemispherical in posterior or lateral views (Fig. 200-201), height about twice width, overall height about 1/3 length of epandrium; phallapodeme and aedeagus fused, in ventral view (Fig. 202) rectangular, lateral margins parallel sided, apex truncate, base rounded, in lateral view (Fig. 203) as a fish tail apically; gonite in lateral view (Fig. 203) broadly bifurcate with dorsal and posterior prongs, both narrow, digitiform, ventral prong slightly longer and more robust, in ventral view (Fig. 202) rod-like, shallowly curved, with a midlength, short, bud-like prong.

Type material.

The holotype male of Hecamedoides ceraceps Cresson is labeled "551/TYPE Hecamedoides CERACEPS E.T.Cresson,Jr. [red; species and generic names handwritten]." The holotype is double mounted (minuten in a rectangular block of pith), is in good condition (some vertigis near exit and entrance of minuten; some mesonotal setae broken; abdomen removed and dissected with the parts in an attached microvial of glycerin), and is deposited in the ANSP (6534).

Type locality.

“BRAZIL.”

Other specimens examined.

URUGUAY. Montevideo: Montevideo (34°53'S, 56°11'W), 21-22 Jan 1927, F. and M. Edwards (1♀; USNM).

Distribution.

Neotropical: Brazil, Uruguay (Montevideo).

Remarks.

This species and Discocerina buccata are apparently closely related, as evidenced by the high gena, which is unique within Discocerina and which was also the reason why both species had been placed in Hydrochasma . Like Discocerina buccata and other congeners in Discocerina , however, Discocerina ceraceps has the phallapodeme fused with the base of the aedeagus, a synapomorphy for these species and other congeners in Discocerina .