Corethrella (Corethrella) inornata Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 77-79

Corethrella (Corethrella) inornata Borkent , new species

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the New World with third palpal segment pale and contrasting with light to medium brown fifth segment ( Fig. 7I), a plain wing (Figs. 62C, 67M), scutum medium brown with some mottled areas ( Fig. 43B), katepisternum completely medium brown or medium brown and with a posterior pale patch, and, nearly completely unpigmented legs but with the following slightly more darkly pigmented: base and apex of forefemur, foretibia, very base of midfemur, very base and, in some, the very apex of the hind tibia ( Fig. 43B).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 7I). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16D). Antenna either uniformly medium brown or with basal half of flagellomere 1 dark brown, remainder medium brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 20F, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus light to medium brown, with segment 3 pale, segment 4 pale to light brown; segment 3 of constant width. Thorax (as in Fig. 43B): Medium brown with scutum with darker patches, katepisternum uniformly pigmented or with pale posterior area, 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. 62C): Apex of R 2 slightly distal to apex of M 1. Plain, without pattern of pigmented veins and/or scales; veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 43B): Nearly completely unpigmented legs but with the following slightly more darkly pigmented: base, apex of forefemur, foretibia, very base of midfemur, very base and, in some, very apex of hind tibia. Femora, tibiae and at least some tarsomeres with broad 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 bilobed in dorsoventral view, with claws subapical (as in Fig. 75E). Elongate claw of foreleg shorter than that of midleg, both longer than those of hind leg. Each claw without inner tooth. Anterior claws of each leg without a basal prong. Foreleg claws unequal. Midleg claws unequal. Foreleg third tarsomere longer than fourth tarsomere. Empodia of intermediate thickness. Abdomen (Fig. 77D): Segments uniformly medium brown. Genitalia (Fig. 87A): Gonocoxite uniformly medium brown, strongly tapering; anteromedial area with distinctively elongate spicules; with well-defined dorsal row of setae, with 3 basal setae of row stout, enlarged and bent subapically, 2 more posterior setae slender, either equal or anterior of these two slightly longer, stouter than posterior one, with row restricted to dorsal portion of gonocoxite. With two dorsomedial stout setae, tapering from base but more abruptly near apex, anterior seta more stout, bases joined by sclerotized plate. Gonostylus (in retracted position) straight, somewhat thick, expanded near midlength or tapering from about midlength, rounded apically; one elongate, thick subbasal seta, situated posteroventrally; apical seta slender, elongate, simple. Aedeagus somewhat triangular, 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 elongate, extending ventrally past ommatida (as in Fig. 16D). Antennal flagellomeres as in Fig. 27E, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17V) squarish. Mandible with large, apically somewhat squared teeth. Palpus as in Fig. 33X. Wing (Fig. 67M). Legs: Apices of fore-, midleg fifth tarsomeres undivided, with claws situated slightly subapically to apically. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Segments uniformly medium to dark brown.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax without spherical sensory pits. Respiratory organ (Fig. 101C): Broadly flattened, with spiracles along outer margin. Abdomen ( Fig. 10C): Segments 3– 7 strongly expanded laterally. Paddle only moderately elongate; apex simple, without socketed spine.

Larva. Undescribed.

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella inornata is known from Costa Rica (Fig. 120B) at altitudes ranging from 1200–2480 m (one label - 2000–2600 m). Specimens have been collected using sweeping, light and Malaise traps, and the holotype and allotype were both reared from larvae collected in bromeliads .

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a common pigmentation pattern, have been collected together at the same locality and time, and the holotype and allotype both had very similar (indistinguishable) larval and pupal exuviae. Although it is likely that the holotype and allotype are conspecific, this name probably applies to two or more species. There was significant variation in the relative length of flagellomere 1, pigmentation of the katepisternum, relative lengths of the femora and tibiae, shape of aedeagus and relative sizes of the two posterior setae in the dorsal row on the gonocoxite. Some differences may be due to the fact that both the holotype and allotype were reared from larvae.

TYPES: Holotype, male adult with associated larval and pupal exuviae on microscope slide, labeled " HOLOTYPE Corethrella inornata Borkent , COSTA RICA, Prov. Alajuela, Upala, Bijagua, ACA-T, P.N. Volcán Tenorio, Falda N.E. del Volcán, 1200m, 28-V-2001, G. Chaverri, En bromelias, LN 295900 426650, LGCh-404" (INBC). Allotype, female adult with associated larval and pupal exuviae on microscope slide Sendero a Rancho Negro, Tapantí National Park, Paraíso, Prov. Cartago, Costa Rica, 1844m, 28-IV-2001 ( INBC). Paratypes: 1 ♂, Madreselva, Foa Los Lagos, Prov. San José, Costa Rica , 2000–2600 m , IX– X-1995 ( INBC); 1 ♀, Sector Cerro Tigre, Barbilla National Park, Cartago, Costa Rica , 1600 m , 19-V–24-VI-2001 ( INBC); 1 ♂, Bratsi, Refugio Valle del Silencio, Limón, Costa Rica , 2472 m , 11-X-2000 ( CNCI); 2 ♀, Refugio Valle del Silencio, Limón, Costa Rica , 2420 m , 6–31-I-1997 ( INBC, CNCI); 8 ♂, 7 ♀, from previous location but 2480 m , 20–26-IX-2003 (4 ♂, 4 ♀, CNCI; 4 ♂, 3 ♀, INBC); 6 ♀, from previous locality but 27-IX–3-X- 2003 ( INBC); 2 ♀, from previous location but 2460 m , 19-VI–5-VII-2003 ( INBC); 1 ♀, from previous locality but 2406 m , 27-VI–5-VII-2003 ( INBC); 6 ♂, 8 ♀, from previous locality but 2475 (or 2480) m , 20-IX–5-X- 2003 ( INBC); 1 ♀, from previous locality but Zona de acampar, 2400 m , 16-IX–16-X-2001 ( INBC); 1 ♀, La Represa, Torre del I. C.E. entre Porras y Villegas Cartago, Paraìso, Tapantí National Park, Costa Rica , 1800 m ,

III-1997 ( INBC); 1 ♂, Orillas Rio Terbi , Andarivel Trail, P.I.L.A., Limón, Costa Rica, 2472m , 27-VI–5-VII- 2003 ( INBC) .

DERIVATION OF SPECIFIC EPITHET: The name inornata (unadorned) refers to the relatively unpatterned appearance of the adults of this species.