Corethrella (Corethrella) pallitarsis Edwards

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 92-94

Corethrella (Corethrella) pallitarsis Edwards

Corethrella pallitarsis Edwards 1930: 532 . Type locality: Lagos, Nigeria. Lectotype female, here designated (BMNH).

Freeman 1962: 43.

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the Afrotropical Region with a midlength wing band (Figs. 62I, 68F) and the hind tibia with poorly defined darker pigmentation at its base and apex of hind tibia and with these blending into medium brown pigmentation at midlength ( Fig. 45B). Also the male is the only Afrotropical species with a midlength wing band (Fig. 62I) and the dorsal row of gonocoxal setae all slender and equal in size (Fig. 88C).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view somewhat circular (as in Fig. 8G). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16F). Antenna light brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 21C, sensilla coeloconica distributed as in Table 1; flagellomere 13 with welldeveloped apical bifurcation. Palpus light brown; segment 3 of nearly constant width. Thorax (as in Fig. 45B): Dark brown. 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. 62I): 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; veins (other than costa and wing margin) with somewhat slender scales. Halter pale, paler than scutellum. Legs (Fig. as in Fig. 45B): Dark brown, with apical 1/5 hind femur somewhat lighter, hind tibia basally, apically darker with non-discrete pigmentation; tarsi light brown. 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. 77J): Medium brown. Genitalia (Fig. 88C): Gonocoxite 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 slender, equal in diameter, length, 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 4/5, evenly curved for apical 1/5, slender, of more or less equal thickness for entire length, tapered apically; without subbasal seta; with short apical peg. Aedeagus slender, elongate, tapering near base, with apical half of constant width, rounded 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 medium brown; with flagellomeres as in Fig. 27L, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17 AC) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 33 AE. Wing (Fig. 68F). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Medium brown, with segment 8, 9 darker. Cercus dark brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella pallitarsis is known from Nigeria and Uganda (Fig. 114) at altitudes ranging from 34 m in Nigeria (types) to at least 621 m in Uganda (its lowest elevation). The latter specimens were merely labeled as “Rift Valley, western Uganda ” and the dot on the distribution map is in that general vicinity. Specimens have been collected using light and Malaise traps. Freeman (1962) additionally recorded a male of this species from Porot Novo, Benin but I was unable to reexamine this specimen to confirm that identification .

TAXONOMIC DISCUSSION: The male and females were associated through the shared presence of a common pigmentation pattern and were collected together in western. The lectotype was originally on a pin but was placed on a microscope slide for this study. The label by J.E. Chainey indicating the specimen is a holotype was an error (Chainey, pers. comm.). A second female from the type series is housed in the BMNH (D. Nooton, pers. comm.) but was not seen; a paralectotype label has been placed on that specimen, which is mounted on a microscope slide.

MATERIAL EXAMINED: Lectotype, here designated, adult female on microscope slide, labeled “ Corethrella pallitarsis Edwards , Lectotype, desig. A. Borkent ”, “ Holotype ”, “Type”, “ Holotype Corethrella pallitarsis Edwards det. J.E. Chainey, 1995", ” Corethrella pallitarsis Edw., F.W. Edwards. det. 1930", “ Nigeria: Lagos, 1-V-1929, C.B. Philip. B.M. 1929-592" ( BMNH). 1 ♂, 2 ♀, Rift Valley , western Uganda, VII-1972 ( CNCI).

DERIVATION OF SPECIFIC EPITHET: The name pallitarsis (pale tarsis) certainly refers to the more lightly pigmented tarsi noted by Edwards (1930).