Corethrella (Corethrella) caribbeana Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 124-126

Corethrella (Corethrella) caribbeana Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World a midlength wing band and no other bands on the wing (some darker scales more basally but not as a distinct subbasal band) (Fig. 63J), with dark brown pleura (as in Fig. 50D), with the apical 0.25 of the midfemur, the apical half of the hind femur and basal 3/4 of the hind tibia equally pale (as in Fig. 50D), abdomen entirely medium brown (sternites 1–2 slightly more darkly pigmented) (Fig. 79A), and the gonocoxite medium brown for at least basal third and lightening apically. Female adult: only extant species of Corethrella in the New World with flagellomeres 1– 3 each short ( Fig. 29J), a midlength wing band and no other bands on the wing (some darker scales more basally but not as a distinct subbasal band) (Fig. 69N), with dark brown pleura ( Fig. 50D), with the apical 0.25 of the midfemur, the apical half of the hind femur and basal 3/4 of the hind tibia equally pale ( Fig. 50D), and the abdomen entirely medium brown (sternites 1–2 not more darkly pigmented).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 11B). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16G). Antenna medium brown); pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 22G, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus pale, with segment 5 slightly pigmented; segment 3 somewhat ovoid, swollen at or near midlength. Thorax (as in Fig. 50D): Medium brown to dark brown with scutum, scutellum slightly lighter, pale sclerites around base of wing, scutellum with darker anteromedial spot. Posterior portion of dorsocentral row with group of about 5 elongate setae. 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. 63J): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of midlength band), with midlength band, some darker scales more basally but not as a distinct subbasal band; veins (other than costa and wing margin) with well-developed scales. Halter pale, paler than scutellum. Legs (as in Fig. 50D): Dark brown with following pale or paler: apex of forefemur, base of foretibia, apical 0.25 of midfemur, basal 0.25 of midtibia, apical half of hind femur, basal 0.75 of hind tibia (some with slight pigmentation at base); slight indication of mid-, hind tarsi with tarsomeres 2–4 with banding. 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 shorter than fourth tarsomere. Empodia slender. Abdomen (Fig. 79A): Light brown, with sternites 1–2 slightly darker, segment 9 dark brown. Genitalia (Fig. 92A): Gonocoxite dark brown basally, light brown apically, gently tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with seta 2 thickest, with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, more or less of even thickness for most of length, tapering near apex. Gonostylus (partially extended) straight for most of length, curved for apical 1/4, slender, expanded subapically, tapered apically; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple. Aedeagus slender, elongate, tapering gradually to apex, pointed apically, with lateral margins fused subapically.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture elongate, extending ventrally past ommatida (as in Fig. 16G). Antennal flagellomeres as in Fig. 29J, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18I) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 34U. Wing (Fig. 69N). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Medium brown, with sternites 1–2 slightly darker, segments 8–9 dark brown. Cercus medium brown.

Immatures. Unknown..

DISTRIBUTION AND BIONOMICS: Corethrella caribbeana is known from the St. Kitts, Dominica, and Costa Rica (Fig. 124) at altitudes ranging from 443–450 m (possibly as high as 500 m). Specimens have been collected by sweeping, Malaise trap and a light trap. The specimens from St. Kitts were swept from near the base of the waterfall of the stream providing water for Sugar Factory.

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a common pigmentation pattern, were collected together in St. Kitts and Dominica (light trap). There is significant variation in the relative sizes of flagellomeres 1–3 in the female specimens from the Dominica (longest), St. Kitts and Costa Rica (shortest) and pattern of sensilla coeloconica on both male and female antennae, suggesting that more than one species may be included under this name.

TYPES: Holotype, male adult on microscope slide, labeled " HOLOTYPE Corethrella caribbeana, Borkent ”, “ 1.6 km N. Basseterre, St. Kitts, 11-XI-1985, A. Borkent, CD454” ( CNCI) . Allotype, female adult on microscope slide, labeled as for holotype (CNCI). Paratypes: 3 ♂, 3 ♀ from type locality ( CNCI) ; 2 ♂, 2 ♀, Harris Soulton Estate , Pont Casse, St. Paul, Dominica, 450 m, 18–19-VI-1965 ( USNM) ; 1 ♀, Estación Quebrada González , Braulio Carrillo National Park, Limón, Costa Rica, 400–500 m, 15-X-2002 ( INBC) .

DERIVATION OF SPECIFIC EPITHET: The name caribbeana is proposed to reflect the partially Caribbean distribution of this species.