Corethrella (Corethrella) squamifemora Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 134-136

Corethrella (Corethrella) squamifemora Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with a pale palpus (as in Fig. 11H), a distinct midlength wing band and with or without more basal dark scales (Fig. 64A), with a dark brown thorax (as in Fig. 52B), dark brown midfemur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) ( Fig. 52B), all femora with slender scales (as in Fig. 74C), and a gonocoxite with a dark base and lightening apically (Fig. 79F). Female adult: only extant species of Corethrella in the New World with a distinct midlength wing band and with or without more basal dark scales on C, Sc and M (Fig. 70F), with a dark brown thorax ( Fig. 52B), dark brown midfemur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur), hind femur with basal 0.58–0.67 darkly pigmented ( Fig. 52B), and all femora with slender scales (Fig. 74C).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 11H). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16F). Antenna pale to light brown, with basal half of flagellomere 1 dark brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 23A, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus pale; segment 3 of nearly constant width. Thorax (as in Fig. 52B): Dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 8 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. 64A): 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 with darker more basal scales restricted to veins C, Sc, M; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 52B): Dark brown with knees of fore-, midlegs pale, basal 0.61–0.68 of hind femur dark, base and apex of hind tibia with non-discrete dark pigmentation, pale at midlength, at least mid-, hind leg tarsomeres 2–4 with banding. Femora, tibiae with slender scales (also 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. 79F): Dark brown. Genitalia (Fig. 93B): Gonocoxite dark brown basally, pale apically, gently tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 1, 2 or 1, 2, 3 slightly thicker than others, 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) to slightly but evenly curved, more curved near apex, slender, of more or less equal thickness for entire length, expanded apically, rounded to somewhat pointed 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 at apex.

Female adult. Descriptive statistics: see Tables 6–11. As for male, with following differences. Head: Coronal suture short, extending ventrally about midway along area between ommatidia (as in Fig. 16F). Antennal flagellomeres as in Fig. 30D, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18O) wide. Mandible with small, pointed teeth. Palpus as in Fig. 34 AA. Wing (Fig. 70F). Legs ( Fig. 52B): As for male but with basal 0.58–0.67 of hind femur dark. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Dark brown. Cercus dark brown.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 102G): Tubular. Abdomen (Fig. 107D): Segments 3–7 somewhat expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Undescribed.

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella squamifemora is known from Mexico south to Costa Rica (Fig. 129) at altitudes ranging from 50–500 m. All adults were reared from bromeliads, except for two males from Costa Rica, one of which was reared from a tire and the other from a plastic container. The specimens from the Belkin “ Mosquitoes of Middle America ” project are identified in Table 12 .

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a common pigmentation pattern and were reared together in Mexico and Nicaragua.

There may be two species present under this name. The specimens from Mexico had dark scales on wing veins C, Sc, and M which were absent in the Nicaraguan and Costa Rican specimens. In addition, the Mexican specimens had two sensilla coeloconica only on flagellomere 12 while the Nicaraguan and Costa Rican specimens had two sensilla coeloconica on each of flagellomeres 10–12. The pupal exuviae of these two groups also differed in details of pigmentation.

TYPES: Holotype, male adult on microscope slide, larval and pupal exuviae on separate slide, labeled " HOLOTYPE Corethrella squamifemora Borkent ,", “ 16 km N. Boca de Tomatlan , El Tuito, Jalisco, Mexico, 500 m, 30-VIII-1972, J.N. Belkin, from bromeliad”, “MEX 723-65, Mexico, 72, Mosq Mid Amer”, “ Corethrella sp. 10 USNM” ( USNM) . Allotype, female adult on microscope slide, larval and pupal exuviae on separate slide, labeled as for holotype but MEX 723-67 ( USNM) . Paratypes: 4 ♂ each with larval and pupal exuviae, 3 ♀ each with larval and pupal exuviae, 3 ♀ each with pupal exuviae, from type locality (2 ♂, 2 ♀ each with larval and pupal exuviae, CNCI; remainder to USNM) ; 2 ♂ each with larval and pupal exuviae, 3 ♀ each with larval and pupal exuviae, 1 ♀ with pupal exuviae, from Bluefields , Zelaya, Nicaragua, 50 m, 23-XI-1971 ( USNM) ; 1 ♂ with pupal exuviae, Carmona Finca Agua Fria , Nandayure, Guanacaste, Costa Rica, 60 m, 5-X- 2000 ( INBC) ; 1 ♂, 1 ♂ with larval and pupal exuviae, 1 ♂ with pupal exuviae, Estación Isla del Caño , Corcovado National Park, Puntarenas, Costa Rica, 90 m, 28-VIII-2000 ( INBC) .

DERIVATION OF SPECIFIC EPITHET: The name squamifemora (scaled femora) refers to the slender scales on the midfemora of adults of this species.