Corethrella (Corethrella) blandafemur Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 65-66

Corethrella (Corethrella) blandafemur Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella with a stout, elongate, and apically expanded bristle on flagellomere 6 ( Fig. 20B). Female adult: only extant species of Corethrella in the New World with a circular head (in anterior view) ( Fig. 7C), with flagellomere 1 moderately elongate ( Fig. 26J), sensilla coeloconica present only on flagellomeres 1, 9–13 and with only a single sensillum coeloconicum on each of 9–13, wing with only setae (Fig. 73C), with uniformly pigmented wing (Fig. 67E), scutum, katepisternum (with or without a very narrow dorsal pale band) (Fig. 71B), and legs (Fig. 71B).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view nearly circular (as in Fig. 7C). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16C). Antenna uniformly medium brown; pedicel without distinctive, more elongate, stout, dorsal or dorsolateral setae; flagellomeres as in Fig. 20B, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation; flagellomere 6 with very elongate stout seta, flattened at apex, broadly bifid at apex ( Fig. 20B). Palpus brown; segment 3 swollen apically. Thorax (as in Figs. 36B, 41B): nearly uniformly brown, dorsal margin of katepisternum with narrow pale margin, posterior portion of posterior anepisternum pale, pale sclerites around base of wing. Posterior portion of dorsocentral row with 2 elongate setae situated somewhat lateral to one another. Prescutal suture elongate, interrupted by area of pale cuticle. Anterior anepisternum divided diagonally. Ventral portion of posterior anepisternum not differentiated from dorsal portion, anterior margin more darkly pigmented than posterior margin. Wing (Fig. 61J): Apex of R 2 basal to apex of M 1. Plain, without pattern of pigmented veins and/or scales; veins (other than wing margin) with only setae. Halter paler to slightly paler than scutellum. Legs (as in Fig. 41B): Uniformly pigmented. 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. Apices of fore-, midleg fifth tarsomeres undivided, with claws slightly subapical to apical (as in Fig. 75F). Claw of foreleg longer than those of mid-, hind leg. Each claw without inner tooth. Anterior claws of each leg without a basal prong. Foreleg claws unequal. Midleg claws equal. Foreleg third tarsomere longer than fourth tarsomere. Empodia thick. Abdomen (Fig. 76J): Tergites, sternites nearly uniformly pigmented brown, with very narrow band of dark brown on posterior margin of each of tergites and sternites 6–7. Genitalia (Fig. 85B): Gonocoxite uniformly medium brown, gently tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with anterior setae of similar thickness as some other setae on gonocoxite, posterior setae slightly thicker, with row curving posteromedially with posteriormost seta of row positioned dorsomedially. With one dorsomedial stout seta, tapering from base. Gonostylus (in retracted position) nearly straight but outer margin slightly concave, thick; of more or less equal thickness for entire length, rounded apically; one elongate, thick subbasal seta, situated posteroventrally; with well-developed apical peg. Aedeagus slender, elongate, tapering gradually to apex, pointed apically, with lateral margins fused at apex.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture absent (as in Fig. 16C). Antennal flagellomeres as in Fig. 26J, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17N) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 33P. Wing (Fig. 67E). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Uniformly brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella blandafemur is known from two localities in Costa Rica: one on the west coast and the other on the east coast (Fig. 119A) at altitudes of 5– 300 m. Specimens have been collected using frog-call and light traps about 200 meters north of where Camino El Peresos crosses Quebra La Catarata in Carara National Park. The holotype male was collected at a light trap run beside the frog-call trap. The specimens from Barbilla National Park were collected with a yellow pan trap. The serrate mandibles of the female adults and their attraction to Hyla gratiosa calls suggest that they feed on frog blood in nature.

TAXONOMIC DISCUSSION: Male and females were associated through the presence of shared pigmentation and were collected together at both known locations. The distinctive and highly modified seta on the male flagellomere 6 ( Fig. 20B) is unique in the Culicomorpha . The male of C. remiantennalis also has a modified seta on flagellomere 10 of its antenna.

TYPES: Holotype, male adult on microscope slide, labeled " HOLOTYPE Corethrella blandafemur Borkent, Manuel Antonio Nacional Park , Costa Rica, 17-XI-1993, A. Borkent , CD1672" ( CNCI) . Allotype, female adult on microscope slide, labeled as for holotype ( CNCI). Paratypes: 2 ♀ labeled as for holotype but CD1671 ( CNCI) ; 1 ♂, 1 ♀, 2 km S. de Estación por la Quebrada, Barbilla National Park , Turrialba, Cartago, Costa Rica, 300 m, 15–18-I-2001 ( INBC) .

DERIVATION OF SPECIFIC EPITHET: The name blandafemur refers to the uniformly pigmented midfemora of this species, a feature shared with many other Corethrella species.