Bicellaria dispar Oldenberg

Barták, Miroslav & Kubík, Štěpán, 2013, Species of Bicellaria Macquart (Diptera: Hybotidae) of Europe, with descriptions of four new species, Zootaxa 3647 (2), pp. 251-278 : 257-258

Bicellaria dispar Oldenberg

( Fig. 47 )

Bicellaria dispar Oldenberg, 1920: 221 .

Taxonomic notes. The species was described on the basis of two males and one female from Tschamintal (=Val di Ciamin, Italy) and one female from Linthal ( Switzerland). There are two specimens in Oldenberg’s collection (SDEI), one male from Tschamintal and one female from Linthal. The male labelled as “Tschamintal 19.6.14 ” “ dispar m.” “ dispar m. Old.”, “coll. Oldenberg” “ Type ” “ Syntypus ” and an unreadable label, was labelled as LECTOTYPE of B. dispar and it is herein designated. The female belongs obviously to a different species (leading in the key near to B. spuria , but it has an unusually pale grey thorax, almost globular broad part of third antennal segment and pale wings with M veins depigmented. This female syntype cannot be identified more precisely because a great part of the abdomen and halteres are missing).

Diagnosis. Small species (wing 1.9 mm long); thoracic setae very short (less than 0.05 mm); antennal stylus together with slender portion of third segment half as long as broadest portion of third segment ( Fig. 47 ).

Redescription. Male. Head black, brownish-grey microtrichose, black setose (occiput with somewhat paler setae). Eyes meeting on frons, facets on dorsal half much larger than on ventral half, about 18 facets in line of contiguity of eyes. One pair of short (0.11 mm) black ocellar setae. Occiput sparsely and short setose, setae approx. 0.06 mm long. Face slightly narrowing ventrally, dorsal part just below antennae about 0.04 mm broad and ventral part about 0.03 mm broad at narrowest point (but very slightly collapsed). Palpus short, brown, hardly visible (retracted within head), probably with 2 setae. Labrum short, brown, lustrous. Antenna black, peculiar and quite distinct among all known European species, with second segment short setose; third segment with single dorsal seta near apex ( Fig. 47 ); ratio of broad part of segment 3: stylus (in 0.01 mm scale) = 15: 6. Thorax brownish black, microtrichose, prescutellar area not paler than remaining parts of mesoscutum. All thoracic setae black, some setae on squama appear paler. Chaetotaxy: acrostichals narrowly biserial (11–12 setae in each row) and very short (0.04 mm); dorsocentrals evenly short and irregularly uniserial, only 2 last pairs somewhat longer; 6–7 setae in posthumeral and intrahumeral areas; 1 longer and 3 slightly shorter postpronotals; notopleura with 2–3 setae; several very short setae in supraalar and prealar areas; 2 pairs of scutellars. Legs including coxae brown, microtrichose and dark setose (some setae appear paler). Fore and mid femora with very short setulae, less than ¼ as long as depth of femur. Fore tibia conspicuously spindle-shaped dilated, very short setose (posteroventrals ¼ as long as depth of tibia). Mid tibia narrow and very short setose, without prominent setae. Hind femur with 18 anteroventrals slightly shorter than depth of femur, arising from small warts, posteroventrals slightly shorter than anteroventrals, dorsal setae not differentiated. Hind tibia very slightly swollen in apical half (0.06 mm at broadest point and 0.04 at narrowest), short setose (all setae shorter than depth of tibia). Tarsi of all legs thin and short setose. Wing clear including apical section of cell sc; vein M depigmented almost throughout length; clear stigma about 0.40 mm long; distance between tips of veins R1 and R2+3 = 0.21 mm. Squama brownish yellow with dark or somewhat faded fringes, halter yellow with dark stem. Abdomen brown, microtrichose, very short setose. Genitalia: (undissected) epandrium and cercus of usual shape and setosity; hypandrium scarcely visible, processes apparently long with long setae along inner margins (about 0.07 mm long); postgonites probably of triangular shape, both phallic hooks equal, rather long and simply bent. Female. Unknown. Length: body 1.8 mm (but somewhat collapsed), wing 1.9 mm.

Distribution. Italy.

Remarks. The specimen is rather immature and long time stored in collection. So it is difficult to decide if some setae are pale or only faded. We decided not to damage this specimen by genital dissection so its description is based on characters which are rather poorly visible. However, we hope that according to the key and redescription it is possible to recognize it easily. The species was omitted in previous studies including those of Tuomikoski (1955) and Chvála (1983) probably because syntypes were not found in the SDEI collection.

Figures

FIGURES 41 – 48. 41 – 44. Hypandrium (ventral view) and phallus with postgonites (lateral view). 41 – 42. Bicellaria uvens Melander. 43 – 44. Bicellaria vana Collin. 45 – 46. Distal part of front tibia and proximal part of front basitarsus (posterior view). 45. Bicellaria spuria (Fallén). 46. Bicellaria vana Collin. 47 – 48. Antennae. 47. Bicellaria dispar Oldenberg. 48. Bicellaria alpina Bezzi (microchaetae mostly omitted). Scale bars = 0.10 mm.