Corethrella (Corethrella) urumense, Miyagi, 1980

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 126-127

Corethrella (Corethrella) urumense Miyagi

Corethrella urumense Miyagi 1980:16 . Type locality: Iriomotejima , Ryukyu Islands, Japan. Holotype (EIHU).

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the Palaearctic and Oriental Regions with the palpus dark brown ( Fig. 11C), a distinct midlength wing band (Figs. 63K, 70A), midfemur uniformly dark brown, midtibia dark brown and with somewhat darker pigmentation basally and apically, and the hind tibia with distinct basal and apical dark pigmentation ( Fig. 51A).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 11C). Four large setae on frons between ventromedial area of ommatida (as in Fig. 16G). Antenna light brown; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 22H, sensilla coeloconica distributed as in Table 1; flagellomere 13 with welldeveloped apical bifurcation. Palpus dark brown; segment 3 of nearly constant width. Thorax (as in Fig. 51A): Dark brown, pale sclerites around base of wing. Prescutal suture elongate, interrupted by area of pale cuticle. 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. 63K): 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 (no dark scales on R 4+5); veins (other than costa and wing margin) with well-developed scales. Halter as dark as scutellum. Legs (as in Fig. 51A): Medium brown with apex of foretibia, base and apex of midtibia, base and apex of hind tibia with non-discrete darker pigmentation, apical 0.3–0.4 hind femur somewhat paler, tarsomeres 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. 79B): Light brown with posterior margin of segment 7 medium brown, lateral margin of segment 8 pale, remainder of segment 8, all of segment 9 medium brown. Genitalia (Fig. 92B): Gonocoxite pale, with apical portion medium brown, parallel-sided for most of length; anteromedial area with spicules similar in length to those elsewhere on gono- coxite; with well-defined dorsal row of setae, with setae 2–5 slightly thicker than others, with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, tapering from base. Gonostylus (extended) slightly curved, slender, tapering from base to apex, somewhat pointed apically; two elongate, slender subbasal setae, situated anteriorly or anteroventrally; apical seta slender, short, simple. Aedeagus slender, elongate, tapering gradually to apex, 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 elongate, extending ventrally past ommatida (as in Fig. 16G). Antenna light brown with base and apex of flagellomere 1, apex of flagellomeres 2–7, all of flagellomeres 8–13 medium brown; with flagellomeres as in Fig. 29K, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 18J) wide. Mandible with small, pointed teeth. Palpus as in Fig. 34V. Wing (Fig. 70A). Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Light brown with segments 8–9 dark brown. Cercus dark brown.

Pupa. Described by Miyagi (1980). Thorax: Scutum, metathorax spherical sensory pits unknown. Respiratory organ: Tubular. Abdomen: Segments 3–7 somewhat expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Described by Miyagi (1980).

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella urumense is known from the southwestern Ryukyu Islands (Fig. 115A) at near sea level. Some paratype material, not examined here, was recorded by Miyagi (1980) from Ishigakijima, an island near the type locality. This site is not included in the distribution map. Male and female adults from the type locality were reared from immatures collected from a small ground pool. Females from Ishigaki, not studied here, were collected with a light trap. Toma et al. (2005) found female adults attracted to a series of frog-call traps, using the simultaneous calls of eight frog species, on Iriomote Island, Japan, June 15–18.

TAXONOMIC DISCUSSION: Males and females were associated through their shared pigmentation pattern and were reared from immatures collected at the same site. The holotype female, one male paratype, and 3 female paratypes were originally on pins and were slide-mounted for this study. Miyagi (1980) noted that some males have 3 subbasal setae on the gonostylus. Miyagi (1980) listed the following as paratypes: 4 ♂, 19 ♀, 11 pupal exuviae, and 12 larvae. I have examined 1 male and 3 females. There are an additional 2 male paratypes in the EIHU and the remainder appear to be missing (I. Miyagi, pers. comm.).

MATERIAL EXAMINED: Holotype, adult female on microscope slide, labeled “ Holotype Corethrella urmense (sic)“, “Ryukyus, Iriomote Is., 25 III 1978, I. Miyagi ” ( EIHU) . Paratypes: 1 ♂, 3 ♀, from type locality (1♂, 2 ♀, USNM; 1 ♀, EIHU) .

DERIVATION OF SPECIFIC EPITHET: The name urumense is derived from "Uruma", an old name for the Ryukyu Islands , which includes the type locality ( Miyagi 1980) .