Corethrella (Corethrella) fusciradialis Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 192-193

Corethrella (Corethrella) fusciradialis Borkent , new species

DIAGNOSIS: Male adult: unknown. Female adult: only extant species of Corethrella with flagellomere 1 very short and nearly globular and flagellomere 3 length about 0.8 of flagellomere 4 ( Fig. 32G), most of wing with dark scales (pale area basal of r-m) and with anterior margin with only slightly differently pigmented scales (Fig. 72I), and hind tibia with distinct subbasal and subapical pigmentation ( Fig. 59C).

DESCRIPTION: Male adult. Unknown. Female adult: Descriptive statistics: see Tables 6–11. Head: Outline in anterior view laterally elongate ( Fig. 15A). Coronal suture short, extending ventrally about midway along area between ommatidia to ventrally past ommatidia (as in Fig. 16F). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16F). Antenna uniformly brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 32G, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Clypeus ( Fig. 18 AR) wide. Mandible with large, triangular teeth. Palpus ( Fig. 35X) pale to very light brown; segment 3 somewhat ovoid, swollen at or near midlength. Thorax ( Fig. 59C): Nearly uniformly 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 short, not extending more than half way to 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. 72I): Apex of R 2 basal to apex of M 1. Anterior margin with nearly uniformly pigmented scales, with a few pale scales distal to darker scales at R 1, otherwise mostly plain, holotype with paler scales along M near m-cu; veins (other than costa and wing margin) with slender scales. Halter as dark as scutellum. Legs ( Fig. 59C): Medium brown, slightly darker at apex of fore-, midtibiae, apical third of hind femur pale, hind tibia with subbasal, subapical darker pigmentation. 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: Segments either uniformly medium brown (holotype) or with tergites 1–3, most sternites light brown, remainder medium brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella fusciradialis is known from three localities in Costa Rica (Fig. 121B) at altitudes of 50–560 m. The holotype and one paratype were collected with an ABC trap using light and octenol. The remaining paratypes were collected with Malaise traps .

TAXONOMIC DISCUSSION: The specimen from Hitoy Cerere was more lightly pigmented than the others in the type series. The coronal suture varied from partially developed to complete in the two specimens from the Osa Peninsula, as well as between the two remaining females. Otherwise, this feature was generally consistent within other species of Corethrella (variable otherwise only in C. ananacola ).

TYPES: Holotype, female adult on microscope slide, labeled " HOLOTYPE Corethrella fusciradialis Borkent , COSTA RICA, Prov. Puntarenas, Osa, Sierpe, ACOSA, P.N. Corcovado, Estación Los Planes, 180 m, 23–24-Julio-2002, G. Chaverri, Trampa ABC-octenal-Luz, LS-287300/499100, #70618" (INBC). Paratypes: 1 ♀ labeled as for holotype ( CNCI) ; 1 ♀, Bosque Ancianos, Boca Tapada, San Carlos , Prov. Alajuela, Costa Rica , 50–100 m, 23-VI–23-VII-2004 ( INBC) ; 1 ♀, Sendero Espavel, Hitoy Cerere, Costa Rica , 560 m, 18-IX–4-X-2003 ( INBC) .

DERIVATION OF SPECIFIC EPITHET: The name fusciradialis (dusky, radius) refers to the darkened wing of the female of this species.