Corethrella (Corethrella) vittata Lane, 1939

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 151-153

Corethrella (Corethrella) vittata Lane

Corethrella vittata Lane 1939b: 390 . Type locality: Juquiá, São Paulo, Brazil. Holotype ♂ (DEFS). Lane 1942: 124, 1953: 92.

Corethrella tripunctata Lane 1942: 120 . Type locality: Carolina, Puerto Rico. Holotype ♂ (USNM). Lane 1953: 89. Lane and Aitken 1956: 538. New synonym.

DIAGNOSIS: Male and female adults: only extant species of Corethrella in the New World with a subapical wing band (with no dark scales on these veins extending to the apex of the wing) (Figs. 64G, 70M) and with the base of the hind tibia pale (dark pigmentation restricted to its apex) ( Fig. 54A).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 12F). Two large setae on frons between ventromedial area of ommatida (as in Fig. 16B). Antenna light brown with flagellomere 1 base, flagellomeres 11–13 slightly darker; pedicel with at least one distinctive, more elongate, stout, dorsal or dorsolateral seta; flagellomeres as in Fig. 23G, sensilla coeloconica distributed as in Table 1; flagellomere 13 with well-developed apical bifurcation. Palpus pale; segment 3 of nearly constant width. Thorax (as in Fig. 54A): Medium brown. Posterior portion of dorsocentral row with group of about 3 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. 64G): Apex of R 2 basal to apex of M 1. Anterior margin with differently, discretely pigmented scales (indicating anterior margin of bands), with four bands of dark scales: basal, subbasal, midlength and subapical, with latter not extending to apex of wing in at least most (possibly in some, the subapical band may extend to the wing apex); veins (other than costa and wing margin) with well-developed scales. Halter pale to light brown, lighter than scutellum. Legs (similar to that in Fig. 54A but see female below): Pale to light brown with following more darkly pigmented: forefemur, apical 1/4 foretibia, midfemur, midtibia with base light brown graduating to medium brown apically, basal ½ hind femur, apical 1/4 hind tibia. Tarsi too rubbed to determine pigmentation pattern. 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. 79L): Medium brown with posterior margin of tergite 7 more darkly pigmented. Genitalia (Fig. 94D): Gonocoxite pigmentation uncertain, likely light brown, parallel-sided for most of length; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with setae 1, 2, thicker than others, with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, tapering from base. Gonostylus (in retracted position) straight for basal 5/6 evenly curved for apical 1/6, slender, narrower at midlength, rounded apically; one elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple. 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 elongate, extending ventrally past ommatida (as in Fig. 16B). Antenna not present. Clypeus ( Fig. 18V) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 35B. Wing (Fig. 70M). Legs ( Fig. 54A): With forefemur, foretibia, midfemora, midtibia dark brown (with pale knees); basal 0.6 hind femur dark brown, apical 0.4 pale; basal 4/5 hind tibia pale, apical 1/5 hind tibia dark brown, at least mid-, hind leg tarsomeres 2–4 with banding. Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Medium brown. Cercus medium brown.

Immatures. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella vittata is known from Puerto Rica, Guyana and Brazil (Fig. 131) at altitudes ranging from 5–85 m. Adult specimens were either reared or were collected by an unknown method. The specimen from the Belkin “Mosquitoes of Middle America” project is identified in Table 12.

Lane (1953) noted that larvae of C. vittata (as C. tripunctata ) were found in crab-holes under rocks but no immature stages were associated with the holotype (the only specimen listed) and the original description did not mention larvae ( Lane 1942). A label on the holotype of C. tripunctata states “crabholes under rocks”, possibly referring only to where the adult was collected. Nevertheless, the holotype appears to be teneral, with the antennae and legs poorly sclerotized, perhaps indicating that the crabholes are indeed the habitat of the immatures (with the adult recently emerged from these).

The single female of C. vittata , from Guyana, was reared from a canal but I could not determine if the exuviae of the immatures were in the collection.

TAXONOMIC DISCUSSION: Males and and the single female were associated through the shared presence of a subapical wing band and pigmentation restricted to the apex of the hind tibia. The association is tenuous, especially considering the geographical distance between all three adult specimens and the fact that the holotype of C. tripunctata appears to be teneral. Because I could not be certain of the extent of the subapical wing band in some specimens, I have keyed the species twice.

The holotype of C. vittata was originally pinned with its genitalia on a microscope slide. All parts are now on the same slide. It is in good condition but is missing one wing and one hind leg. The holotype of C. tripunctata was originally on a pin with its genitalia mounted between two small glass coverslips and also placed on the pin. All parts are now on one microscope slide. The specimen is in poor condition, with one wing and one midleg missing, appearing to be teneral (see above) and with the previously mounted genitalia in bad condition, with only a crushed gonocoxite and part of segment 9 remaining.

The male genitalia of the holotype of C. tripunctata had a more slender dorsomedial seta than the holotype of C. vittata but it is uncertain what this means. Clearly, more specimens are needed to confirm the synonymy proposed here.

Lane (1939b:391) recorded a female allotype and 2 female paratypes for C. vittata which I have not been able to locate. Lane and Aitken (1956) designated a female allotype for C. tripunctata but it has no formal status because it was designated after the original description by Lane (1942).

MATERIAL EXAMINED: Holotype, adult male now all on microscope slide, originally pinned portion of specimen labeled “ Corethrella vittata Lane , 39", “holotypo”, “ S. Paulo, Juquiá, J. Lane col.”, “1.042”, “1.148”, “S.97, T.955”, male genitalia on slide labeled “Universidade de S. Paulo Instituto de Higiene parasitologia, Corethrella vittata Ln, 1939 , S. Paulo, Juquiá, Lane, 1.148 Hyg ♂, No. 1042, Lamina 268, Divisao 5, Gavela 135” ( DEFS) . Holotype, adult male on microscope slide, labeled “ Corethrella tripunctata Lane , 41”, “holotipo”, “ Carolina Porto Rico alt. 100 ft ”, “Thru Miss Ludlow”, “crabholes under rocks Sep. 11, 1914 ” ( USNM) . 1 ♀, Botanical Gardens , Demerara, Georgetown, Guyana, 5 m, 7-XI-1967 ( USNM) .

DERIVATION OF SPECIFIC EPITHET: The name vittata (bound with a ribbon) may refer to the stripes on the thorax of the dried specimens Lane (1939b) described for this species.