Corethrella (Corethrella) briannae Borkent, 2008

Published, First, 2008, The Frog-Biting Midges of the World (Corethrellidae: Diptera), Zootaxa 1804, pp. 1-456 : 103-104

Corethrella (Corethrella) briannae Borkent , new species

DIAGNOSIS: Male adult: only extant species of Corethrella in the New World with a distinct midlength wing band (Fig. 62N), with the scutum mostly light brown but with the posterior anepisternum, most of the anepimeron and the katepisternum dark brown, midfemur light to medium brown and equal to that of base of hind femur, base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) (as in Fig. 47A), gonocoxite pale and contrasting with medium brown tergite 9 (Fig. 78C). Female adult: only extant species of Corethrella in the New World with each of flagellomeres 1–3 moderately elongate ( Fig. 28G), flagellomere 3 without a sensillum coeloconicum, flagellomere 12 with 2–3 sensilla coeloconica, a distinct midlength wing band (Fig. 68M), with the scutum mostly light brown but with the posterior anepisternum, most of the anepimeron and the katepisternum dark brown, midfemur uniformly light to medium brown and equal to that of base of hind femur, and the base of hind tibia darkly pigmented (contrasting with pale apex of hind femur) ( Fig. 47A).

DESCRIPTION: Male adult. Descriptive statistics: see Tables 2–5. Head: Outline in anterior view laterally elongate (as in Fig. 9E). 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. 21H, sensilla coeloconica distributed as in Table 1; flagellomere 13 with welldeveloped apical bifurcation. Palpus pale; segment 3 somewhat ovoid, swollen at or near midlength. Thorax (as in Fig. 47A): Scutum light brown, with very anterolateral area medium brown; scutellum, mediotergite light brown; pleura mostly light brown with posterior portion of anterior anepisternum, most of posterior anepisternum, most of anepimeron, all of katepisternum dark brown, pale sclerites around base of wing. Posterior portion of dorsocentral row with group of about 6 elongate setae. Prescutal suture elongate, interrupted by area of pale cuticle. 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. 62N): 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, some with more basal darker scales on C, A; veins (other than costa and wing margin) with well-developed scales. Halter pale. Legs (as in Fig. 47A): Mostly light brown, with slightly darker pigmentation on apical portion of foretibia, base and apex midtibia, hind femur with apical 2/3 pale, hind tibia with basal and apical dark brown discrete pigmentation, at least mid-, hind leg tarsomeres 2–4 with banding. 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. 78C): Light brown, with sternites 1–2 dark brown, tergite 9 medium brown. Genitalia (Fig. 89D): Gonocoxite pale, strongly tapering; anteromedial area with spicules similar in length to those elsewhere on gonocoxite; with well-defined dorsal row of setae, with seta 2 or setae 2–4 thicker than others, with row restricted to dorsal portion of gonocoxite. With one dorsomedial stout seta, more or less of even thickness for most of length, taper- ing near apex. Gonostylus (partially extended) straight for most of length, curved apically, slender, slightly tapering for most of length, somewhat expanded apically, apex pointed; one somewhat elongate, slender subbasal seta, situated anteriorly or anteroventrally; apical seta slender, elongate, simple. Aedeagus slender, elongate, tapering from base, 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 short, extending ventrally about midway along area between ommatidia (as in Fig. 16F). Antennal flagellomeres as in Fig. 28G, sensilla coeloconica distributed as in Table 1. Clypeus ( Fig. 17 AJ) squarish. Mandible with small, pointed teeth. Palpus as in Fig. 34F. Wing (Fig. 68M): similar to male but with additional somewhat darkened scales in basal band. Legs: Claws of each leg equal to those of others; equal on each leg, simple (without inner teeth). Abdomen: Light brown with sternites 1–2, segments 8–9 dark brown. Cercus pale.

Pupa. Mostly undescribed. Thorax: Scutum, metathorax each with spherical sensory pit (as in Fig. 100A). Respiratory organ (Fig. 101I): Tubular. Abdomen (Fig. 105D): Segments 3–7 somewhat expanded laterally. Paddle only moderately elongate; apicodorsal thick spine articulating; apicoventral seta longer than thick spine.

Larva. Undescribed.

Egg. Unknown.

DISTRIBUTION AND BIONOMICS: Corethrella briannae is known only from the type locality in Ecuador (Fig. 123) at an altitude of 280 m. Specimens have been reared from immatures collected from the leaf axils of Heliconia and Montrichardia (a terrestrial aroid). The specimens from the Belkin “Mosquitoes of Middle America” project are identified in Table 12.

TAXONOMIC DISCUSSION: Males and females were associated through the shared presence of a distinctive pigmentation pattern and were reared together from the same locality. One male paratype (ECU 164) had deformed gonostyli with these being compressed and more curved apically and one with two subbasal setae (one of these small).

TYPES: Holotype, male adult on microscope slide, larval and pupal exuviae on separate slide, labeled " HOLOTYPE Corethrella briannae Borkent , 86 km E Guayaquil on Tr. 8, Cochancay , Canar, Ecuador, 280 m, 13-II-1966, J.N. Belkin, Leaf axils of Heliconia ", “ Corethrella sp. 14”, “ECU 165-20, Ecuador, 65–66, Mosq Mid Amer” ( USNM) ; allotype, female adult on microscope slide, larval and pupal exuviae on separate slide, labeled as for holotype ( USNM) . Paratypes: 2 ♂ each with pupal exuviae, 1 ♂, 1 ♀ with pupal exuviae, 1 pupal exuviae, 5 fourth instar larvae, all from type locality (1 ♂ with pupal exuviae to CNCI; remainder to USNM) .

DERIVATION OF SPECIFIC EPITHET: The name briannae is proposed for my wonderful daughter-inlaw Brianna Borkent, not only because I am so proud to have her in my life and to experience her love but also in recognition of her lively spirit and talented writing (as Brianna Brash-Nyberg).