Corethrella (Corethrella) tarsata Lane, 1942

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 129-130

Corethrella (Corethrella) tarsata Lane

Corethrella tarsata Lane 1942:102 . Type locality: Camassary, Baia [= Bahia], Brazil. Holotype ♂ (BMNH). Lane 1953:71. Lane and Aitken 1956:537.

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the New World with a plain wing (Figs. 63L, 70B) and with the thorax nearly uniformly dark brown ( Fig. 51B) but with the scutellum lighter laterally and with a median, longitudinal, dark stripe.

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 11D). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16G). Antenna pale or very light brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 22I, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus dark brown; segment 3 of constant width. Thorax (as in Fig. 51B): Nearly uniformly dark brown, scutellum with darker anteromedial spot. Posterior portion of dorsocentral row with group of about 10 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. 63L): Apex of R 2 basal 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 scutum. Legs (as in Fig. 51B): Medium brown, with hind femur with apical half pale but with small ventral subapical patch of darker pigment, hind tibia with basal and apical darker, discrete pigmentation, tarsomeres 1–4 of fore-, midleg, tarsomeres 2–4 of hind leg each with basal darker band. With only setae, with some somewhat thicker (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. 79C): Nearly uniformly light to medium brown, with following darker: sternites 1–2, posterior margin of each of sternites 6, 7, and segment 8, all of segment 9. Genitalia (Fig. 92D): Gonocoxite pale, with apical 0.4 medium brown, strongly tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae stouter than other scattered setae on gonocoxite, with setae 2, 3 thicker than others, with row curving posteromedially with posteriormost seta of row positioned dorsomedially. With one dorsomedial stout seta, more or less of even thickness for most of length, tapering near apex. Gonostylus (in retracted position) straight for basal 3/4, curved apically, slender, tapering from base to apex, tapered apically; one elongate, slender, subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple. Aedeagus slender, elongate, tapering gradually to apex, rounded 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 1–2 pale, flagellomeres 3–13 light to medium brown; with flagellomeres as in Fig. 29L, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18K) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 34W. Wing (Fig. 70B). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Segments light brown, with sternite 2 darker, cercus pale or light brown.

Pupa. Described by Lane and Aitken (1956). Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 102E): Tubular. Abdomen (Fig. 107B): Segments 3–7 not expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Described by Lane and Aitken (1956).

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella tarsata is known from Trinidad and Tobago and Brazil (Fig. 129) at altitudes ranging from 0–40 m. The holotype was collected in a house and the remaining specimens, from the Belkin “Mosquitoes of Middle America” project ( Table 12), were reared from either a pupa (♂) or from larvae (♀) from bromeliads from Trinidad and Tobago .

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a distinctive pigmentation pattern and had similar pupal exuviae. The holotype was originally on a pin, with the genitalia in poor condition on a piece of coverslip on the pin. All parts are now on a microscope slide. The holotype is missing one wing, the hind tarsi, one palpus and segments 4–5 of the other, and the remaining parts are in poor condition. The male genitalia was sufficiently preserved to allow study of most parts, including the distinctive aedeagus. The pigmentation of the thorax, legs and abdomen was similar to the male from Trinidad and Tobago .

The specimens studied by Lane and Aitken (1956) were not reexamined here but their characterization of the distinctive female adult matches those described here. I therefore consider their description of the immature stages of this species to be correct. The three pupal and two larval exuviae studied here also match the description by Lane and Aitken (1956).

MATERIAL EXAMINED: Holotype, adult male on microscope slide, labeled “ Corethrella tarsata Lane, 1941 , holotipo, HOLO Type, Brasil: Bahia, Dr. H.W. Kumm. B.M. 1931–302, In house, Camassary” ( BMNH). 1 ♂, pupal exuviae, St. Andrew, Guaico-Tamana Rd. 12 3/4 milepost, 100 m, Trinidad and Tobago, 10-VI-1965 ( USNM); 2 ♀, each with pupal, larval exuviae, St. George , near Arima, Pinto Rd. , Trinidad and Tobago, 40 m, 8-VII-1965 ( USNM).

DERIVATION OF SPECIFIC EPITHET: The name tarsata likely refers to the patterned pigmentation on the tarsi of this species.