Cerodontha (Dizygomyza) pseudonigrihalterata Boucher, n. sp.

(Fig. 6)

urn:lsid:zoobank.org:act: D8EB99BF-D8FE-442C-B9D8-16B4C8A5E4A2

TYPE MATERIAL. — Holotype. Guyane • ♂; Mitaraka, sampling site: MIT-E-savane roche 2; 02°13’59.8”N, 54°27’46.5”W; 471 m; open/ partially opened areas; 13-20.VIII.2015; MT (6 m); Pierre-Henri Dalens leg.; sample code: MITARAKA/230, sorted by M. Pollet; MNHN.

ETYMOLOGY. — The specific name is derived from the Greek word “Pseudo” meaning false and refers to the similarity of this species to Cerodontha (Dizygomyza) nigrihalterata Boucher, 2005 .

DIAGNOSIS. — This species can be differentiated from all other Cerodontha (Dizygomyza) species by the combination of the following characters: knob of halter completely brown, only one ors, wing infuscated in cell R 1 and R 2+3, only 2 dc, male with first flagellomere small, patch of reclinate orbital setulae at level of ori; frons not projecting in front of eye in profile.

DISTRIBUTION. — French Guiana.

HOST. — Unknown.

DESCRIPTION

Male

Orbital plate not projecting in front of eye in profile (Fig. 6A); orbital plate broad, 0.37 × width of frons at midpoint and only slightly widening anteriorly; width of frons including orbital plates 0.30 mm at midpoint; eye seemingly bare, at most with a few scattered hairs; lunule broad, partly covered by large orbital plate (Fig. 6B); lunule and anterior orbital plate with a patch of silvery pubescence (Fig. 6B) especially in posterodorsal view; orbital plate and ocellar triangle shining; frons with black microtomentum; one reclinate ors and three ori (anterior two inclinate and upper ori lateroclinate on one side); orbital setulae reclinate, numerous, forming a patch at level of ori; first flagellomere small (Fig. 6A), rounded apically with short white pubescence, longer posteriorly; arista long (0.5 mm) with long pubescence (Fig. 6A); small raised keel present between antennae; gena at midpoint about 0.16 × of maximum eye height; clypeus medium width with upper margin rounded, slightly projecting and distinctly visible in lateral view; palpus with 7-9 long hairs apically (Fig. 6A); two postsutural dc; prsc absent; acrostichal setulae in 7-8 rows; mid tibia with one long apical seta of approximately 0.15 mm (Fig. 6E); wing length approximately 1.9 mm (wing bent); last section of M 4 approximately 0.7 × length of penultimate section; wing conspicuously infuscated in cell R 1 and R 2+3.

Colour

Body completely brown, except for orbital plate yellowish anteriorly (Fig. 6B) and base of first flagellomere and base of arista yellowish; halter with knob completely brown, stalk paler; legs brown, with tarsi at most slightly paler; calypter yellow, fringe short and pale brown.

Male genitalia

Distiphallus in the form of two tubules, almost equal in length as mesophallus and with a short, square, terminal process (Fig. 6C, D); hypandrium broad and rounded; epandrium with apical long hairs (Fig. 6F); surstylus with five spines (only three visible in Fig. 6F); subepandrial sclerite (“Langfortsatz”) narrow, elongate (Figs 6F); anal projection of epandrium prominent, longer than wide; ejaculatory apodeme with short stalk (Fig. 6G).

REMARKS

This species is most similar to the Costa Rican C. (Diz.) nigrihalterata Boucher, 2005 (Fig. 7). An attempt was made to have both species barcoded, which ultimately failed (Boucher & Savage 2022). Externally the two species have a few important similarities including the presence of only one ors and three ori, dark knob of halter, wing infuscated in cell R 1 and R 2+3, lunule and anterior orbital plate with silvery pubescence and mid tibia with a strong apical spine. The phallus of both species is also similar. The holotype of C. nigrihalterata illustrated in Boucher (2005) has the distal tubules of the phallus divergent, but it is parallelsided (as seen in C. (Diz.) pseudonigrihalterara Boucher, n. sp.) in a paratype shown in Fig. 7C, D. Cerodontha (Diz.) nigrihalterata differs from the new species described here by having a projecting frons (Fig. 7A), the palpus with normal setae, the first flagellomere slightly enlarged in the male (Fig. 7B), tarsal segments paler yellow, mesonotum with three postsutural dc, the ejaculatory apodeme with a long and narrow stalk (Fig. 7E, paratype (slightly different from ejaculatory apodeme in holotype illustrated in Boucher 2005)) and apex of distal tubule more contiguous with tubule, not appearing as a separate sclerite. However, the unique characteristics that these species share make them distinct within the genus Cerodontha, suggesting a close evolutionary relationship.