Corethrella (Corethrella) incompta Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 182-184

Corethrella (Corethrella) incompta Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with flagellomeres 9-12 each with two sensilla coeloconica, a distinct midlength wing band (Fig. 65G), thorax dark brown (as in Fig. 57C), halter and scutellum equally dark brown, 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), with apical 0.3-0.4 of hind tibia pale (as in Fig. 57C), midfemur without scales, and base of gonocoxite medium brown and similar in pigmentation to segment 9 (Fig. 81B). Female adult: only extant species of Corethrella in the New World with flagellomeres 2 and 3 moderately elongate ( Fig. 32A), flagellomeres 9-12 each with two sensilla coeloconica, a distinct midlength wing band with dark scales present on all veins and more basal dark scales only on C, Sc, R and in some, on M (Fig. 72A), thorax dark brown ( Fig. 57C), halter and scutellum equally dark brown, midfemur thick, dark brown and equal to that of base of hind femur, with apical 0.3-0.4 of hind tibia pale, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) ( Fig. 57C), and midfemur without scales.

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2-5. Head: Outline in anterior view laterally elongate (as in Fig. 14B). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16E). Antenna light to medium brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 24J, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus medium brown; segment 3 of nearly constant width, slightly swollen apically. Thorax (as in Fig. 57C): Medium to 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. 65G): 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, more basal dark scales only on C, Sc, R and in some, on M; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 57C): Dark brown, with fore-, midleg knees pale, apical 0.3-0.4 hind femur pale, hind tibia with non-discrete to somewhat discrete basal and apical dark pigmentation. With only slender setae, these slightly thick, 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. 81B): Medium brown, with posterior margins of each of tergites 5-7 slightly darker, segment 9 more darkly pigmented. Genitalia (Fig. 98B): Gonocoxite with base medium brown (equal or slightly lighter than tergite 9), uniformly pigmented or in some slightly lightening apically, gently tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 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) straight or gently curved, slender, of more or less equal thickness for entire length, pointed apically; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple or plumose. 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, barely extending to area between ommatidia (a bit long than in Fig. 16E). Antenna medium to dark brown; with flagellomeres as in Fig. 32A, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18 AJ) squarish. Mandible with moderately sized, pointed teeth. Palpus as in Fig. 35P. Wing (Fig. 72A). 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.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella incompta is known from Mexico, Cayman Islands, Costa Rica, Ecuador, French Guiana , and Brazil (Fig. 130) at altitudes ranging from 0-269 m. Specimens have been collected using light, Malaise , and frog-call traps. I found this species to be relatively common in frog-call traps at La Selva Biological Station, Costa Rica on March 2, 2004 but otherwise collected only two females with a frog-call trap at Cahuita National Park, Costa Rica on Oct. 30, 1993 (the trap was run Oct. 28- 30, 1993 without otherwise sampling this species). The serrate mandibles of the female adults and their attraction to Hyla gratiosa calls suggest that they feed on frog blood in nature. The specimens from the Belkin “Mosquitoes of Middle America” project are identified in Table 12 .

A female from Tocumen, Panama (USNM) keyed to C. incompta but the first two flagellomeres were somewhat shorter than was otherwise present in this species. It had been previously identified as C. selvicola . It may represent a new species but further collecting and study is needed.

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a common pigmentation pattern and the presence of two sensilla coeloconica on flagellomeres 10–12. Males and females have been collected together in Mexico and in Costa Rica.

Some Mexican specimens had been previously identified by H. Huerta as C. laneana but these were misidentifications. Much of the Mexican material was dehydrated in alcohol and the heads, thoraces and abdomen could not be completely cleared when preparing slide mounts.

The female holotype of C. striata (DEFS) was similar to C. incompta but was unfortunately missing its antennae so that it could not be confidently interpreted. The female of C. striata had a relatively longer third palpal segment 3 and the wing was also longer (1.24 mm) than that of C. incompta (0.94-1.10 mm). The holotype was previously on a pin but has been mounted on a microscope slide for this study. Lane (1942) described a paratype female which I was unable to locate. If it is located it may allow for the accurate identification of C. striata .

TYPES: Holotype, male adult on microscope slide, labeled " HOLOTYPE Corethrella incompta Borkent ”, “ COSTA RICA, Prov. Puntarenas, R.V.S. Rio Piro, Entrada a Finca Catlino, 40 m, 14-21 SEP 2004, B. Gamboa, D. Briceño, M. Moraga., Y. Cardenas. Malaise, LS 262284 535746, #78237” (INBC). Allotype, female adult on microscope slide, labeled as for holotype (INBC). Paratypes: 1 ♂, Loma Bonita , Reserva Celestun , Yucatán, Mexico, 5-6-IX-1995 ( IDRE) ; 4 ♀, from previous locality but 5-6-XII-1995 (3 ♀, IDRE; 1 ♀, CNCI) ; 3 ♂, Las Coloradas, km 10 Carretera Ria Largartos, Peten Tucha, Mpio Ria Largartos, Reserva Ria Largartos , Yucatán, Mexico, 0-15 m, 4-IV-1997 (2 ♂, IDRE; 1 ♂, CNCI) ; 1 ♂, 1 ♀, km 15 Carretera Celestun- Kinchil , Celestun , Reserva Ria Celestun , Yucatán, Mexico, 0-15 m, 24-X-1996 ( IDRE) ; 2 ♂, from previous locality but 14-15-X-1996 ( IDRE) ; 1 ♂, Ojo de Agua , Reserva Ria Celestun , Yucatán, Mexico, 0-15 m, 30- VIII-1995 ( IDRE) ; 2 ♂, 1 ♀, Peten Tucha, Reserva Ria Celestun , Yucatán, Mexico, 0-15 m, 1-IX-1995 ( IDRE) ; 1 ♂, Reserva Ría Lagartos, km 10 Carretera , Río Lagartos-Las Coloradas , Yucatán, Mexico, 0-15 m, 1-IX-1995 ( IDRE) ; 3 ♀, km 7.5 Carretera Celestun-Kinchil, Celestun , Reserva Ria Celestun , Yucatán, Mexico, 0-15 m, 8-9-IV-1997 ( IDRE) ; 1 ♀, Trail N South West Sound mangrove area, Georgetown , Grand Cayman, Cayman Islands, 4 m, 9-IX-1968 ( USNM) ; 1 ♀, Estación Los Patos, Corcovado National Park , Golfito, Costa Rica, 70 m, 25-XII-2000 - 13-II-2001 ( INBC) ; 1 ♀, Quebrada a Rio Madrigal, Corcovado National Park ,

Golfito, Costa Rica, 40 m, 14-III-6-IV-2003 (INBC); 5 ♀, La Selva Biological Station , Puerto Viejo de la Sarapiqui, Heredia, Costa Rica, 40 m, 1-III-2004 ( CNCI) ; 10 ♀, as for previous locality but 2-III-2004 (4 ♀, CNCI; 3♀, USNM; 3 ♀, INBC) ; 5 ♀, 5 km E Cahuita , Costa Rica, 3 m, 30-X-1993 ( CNCI) ; 3 ♀, previous locality but 29-X-1993 ( CNCI) ; 1 ♀, 5 km SE Cayenne , Guyane, French Guiana, 5 m, 2-3-II-1965 ( USNM) ; 1 ♀, IPEAN, Belem, Para, Brazil, 30 m, 28-29-IX-1970 ( USNM) ; 1 ♀, Pastaza, Napo River, Ecuador, 14-22-V- 1965 ( CNCI) .

DERIVATION OF SPECIFIC EPITHET: The name incompta (unadorned) refers to lack of obvious distinctive features to separate this from other similar species.