Corethrella (Corethrella) dicosimoae Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 195-197

Corethrella (Corethrella) dicosimoae Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with the clypeus nearly square (as in Fig. 18 AU), flagellomere 3 without a sensillum coeloconicum and 10–12 each with one sensillum coeloconicum, a distinct midlength wing band (Fig. 65J), thorax dark brown (as in Fig. 60B), halter pale and lighter than scutellum, midfemur dark brown and equal to that of base of hind femur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur), tarsomeres uniformly brown (as in Fig. 60B), midfemur without scales, and segments 8, 9 and base of gonocoxite similarly pigmented and with gonocoxite lightening apically (Fig. 81E). Female adult: only extant species of Corethrella in the New World with the clypeus nearly square ( Fig. 18 AU), flagellomeres 2 and 3 elongate ( Fig. 32J), flagellomere 3 without a sensillum coeloconicum, flagellomeres 9–12 each with one sensillum coeloconicum, a distinct midlength wing band, with dark scales basal to the midlength band restricted to anterior veins (so that the scales along the posterior margin of the wing basal to the midlength band are more or less unicolorous, except for some darkened posterior scales at very base of wing) (Fig. 72L), thorax dark brown ( Fig. 60B), halter pale and lighter than scutellum, midfemur dark brown (with very apex pale) and equal to that of base of hind femur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) but this pigmentation not discrete, tarsomeres uniformly brown ( Fig. 60B), and midfemur without scales.

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 15D). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16F). Antenna medium brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 25B, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus pale or light brown; segment 3 of nearly constant width. Thorax (as in Fig. 60B): Dark brown, pale sclerites around base of wing. 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. 65J): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margins of wing bands), with more basal dark scales on C, Sc, M, distinct midlength band present; veins (other than costa and wing margin) with well-developed scales. Halter pale. Legs (as in Fig. 60B): Medium to dark brown, with fore-, midleg knees pale, hind femur with apical 0.4 pale, hind tibia pale with basal and apical non-discrete dark brown 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. 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. 81E): Medium brown. Genitalia (Fig. 99A): Gonocoxite medium brown basally, with apical portion more lightly pigmented, parallel-sided for most of length; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 2, 3, 4 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 (in retracted position) straight for most of length, slightly curved apically, somewhat narrowed at midlength, 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). Antenna; with flagellomeres as in Fig. 32J, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18 AU) squarish or somewhat wider than long. Mandible with small, pointed teeth. Palpus ( Fig. 35 AA) somewhat swollen, pigmentation as for male. Wing (Fig. 72L): as for male or without dark scales basal to midlength band. Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Medium brown with segments 8–9 dark brown. Cercus dark brown.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 103K): Tubular. Abdomen (Fig. 111D): 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 dicosimoae is known from the Bahama Islands , French Guiana and Peru (Fig. 124) at altitudes ranging from 5–106 m. Specimens have been collected using light and Malaise traps. The specimens from the Bahama Islands were reared from a semipermanent pond in full sun, with clear water, flotage present and the bottom with mud and dead plant matter. Material from the Belkin “Mosquitoes of Middle America” project is listed in Table 12 .

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a common pigmentation pattern and antennal structure and were reared together from one locality in the Bahama Islands.

Nearly all specimens from South America differed from the specimens from the Bahama Islands in lacking dark scales basal to the midlength band. One specimen from French Guiana had slightly darkened scales on R, Sc and R but lacked those on M (present in the Bahamian material). This may indicate that there are two species present under this name.

TYPES: Holotype, male adult on microscope slide, larval and pupal exuviae on separate slide labeled " HOLOTYPE Corethrella dicosimoae Borkent ”, “ Corethrella sp. 30 USNM”, “Gambier, New Providence, Bahama Islands, 26-VII-1972, S.J. Chew, T.E. Rogers. Pond, semipermanent water”, “BAH 6–11 Bahamas 72 Mosq Mid Amer” (USNM). Allotype, female adult on microscope slide, pupal exuviae on separate slide, labeled as for holotype but BAH 6-105 ( USNM) . Paratypes: 1 ♀ with larval and pupal exuviae, 1 ♀ with pupal exuviae, from type locality ( CNCI) ; 7 ♀, 24 km SW Cayenne , Guyane, French Guiana, 5 m, 1–2-II-1965 ( USNM) ; 1 ♀, 23 km S Cayenne , Guyane, French Guiana, 5 m, 4–5-II-1965 ( USNM) ; 2 ♀, Quisto Cocha , Iquitos, Loreto, Peru, 8–10-II-1984 ( CNCI) .

DERIVATION OF SPECIFIC EPITHET: The name dicosimoae is named for Joanne DiCosimo, President and Chief Executive Officer of the Canadian Museum of Nature, in recognition of her support of studies of biodiversity both in Canada and at INBio in Costa Rica.