Corethrella (Corethrella) pauciseta Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 191-192

Corethrella (Corethrella) pauciseta Borkent , new species

DIAGNOSIS: Male adult: unknown. Female adult: only extant species of Corethrella in the Oriental, Australasian, and Oceanic Regions with a clypeus with about 5 setae, plain wing (Fig. 72H), veins (other than along the wing margin) with definite but slender scales (as in Fig. 73B), and uniformly medium to dark brown thorax ( Fig. 59B).

DESCRIPTION: Male adult. Unknown.

Female adult. Descriptive statistics: see Tables 6–11. Head: Outline in anterior view laterally somewhat circular ( Fig. 14I). Coronal suture elongate, extending ventrally past ommatida (as in Fig. 16B). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16B). Antennal flagellomeres 1–4 medium brown, remainder unknown; pedicel without distinctive, more elongate, stout, dorsal or dorsolateral setae; flagellomeres as in Fig. 32F, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18 AQ) squarish or somewhat wider than long. Mandible with small, pointed teeth. Palpus ( Fig. 35W) brown; segment 3 likely of nearly constant width (partially compressed in preparation). Thorax ( Fig. 59B): Uniformly medium to dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with 2 elongate setae situated somewhat lateral to one another. Prescutal suture elongate, thick, uninterrupted, extending to near dorsocentral row of setae. Anterior anepisternum divided diagonally by sinuous suture, dorsal portion about equal to ventral portion. Ventral portion of posterior anepisternum triangular, uniformly brown, with anterodorsal margin thick. Wing (Fig. 72H): Apex of R 2 slightly distal to apex of M 1. Plain, without pattern of pigmented veins and/or scales; veins (other than costa and wing margin) with slender scales. Halter as dark as scutellum. Legs ( Fig. 59B): Medium brown, but slightly lighter on midportion of fore-, mid-, hind tibiae. With only slender setae, lacking scales (except for some in patch of whip-like setae on posterior portion of hind tibia). Midleg with thick, subapical setae on each of at least tarsomeres 1–3. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Empodia slender. Abdomen: Uniformly medium to dark brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella pauciseta is known only from the single holotype from Hospital Creek, Wau, Papau New Guinea (Fig. 115B) at an altitude of 1250 m. It is uncertain how the specimen was collected. The recently examined female very similar to C. pauciseta noted below indicates that C. pauciseta likely belongs to at least a clade of frog-biters (it is presently unplaced phylogenetically).

TAXONOMIC DISCUSSION: The holotype was originally on a pin and subsequently placed on a microscope slide. It is missing flagellomeres 5–13 of its right antenna and all of its left antenna. A female similar to C. pauciseta was collected on a tributary of Sungai Belalong in the Temburong district of Brunei Darussalam, Brunei (115° 09'E, 4° 33'N, 50 meters, 7-VIII-2006, U. Grafe; 1 ♀, to collector) using a frog-call trap broadcasting the call of Hyla gratiosa . It had only 2 setae on the clypeus and well-developed scales on the wing. It almost certainly represents an undescribed species.

TYPES: Holotype, female adult on microscope slide, labeled " HOLOTYPE Corethrella pauciseta Borkent ”, “NE NEW GUINEA: Wau , Hospital Ck. 1250 m, 10.IV.1965 ”, “ P. Shanahan Collector BISHOP” ( BPBM).

DERIVATION OF SPECIFIC EPITHET: The name pauciseta refers to the few setae present on the clypeus of the female adult of this species.