Corethrella trivittata Amaral & Pinho sp. nov.

urn:lsid:zoobank.org:act: 24AD1114-30CF-4DE1-A35D-91A8BA9C4865

Figs. 11–12

Type material. Holotype: ♂ adult: CUBA, Guantanamo province, Baracoa Municipality, Alejandro de Humboldt National Park, Monte Iberia, 20°27'22.30"N, 74°44'16.88"W. Malaise trap. VI.2017, Orestes Bello-González leg. (Cuba25) (PERC).

Etymology. The specific epithet refers to the presence of three bands on the wing.

Diagnosis. Adult male. Only extant species of Corethrella with the wing without dark scales just distal to the arculus (Fig. 11E); with dark scales making a subapical band (with no dark scales on these veins extending to the apex of the wing); hind femur with the base pigmented, apical 0.4 pale (Fig. 11C); with abdominal segment VIII with same degree of pigmentation as segment IX (Fig. 11F).

Description

Adult male (n = 1).

Head (Fig. 11A). Medium brown. Outline of head in anterior view laterally elongate; head W/L 1.65. Coronal suture complete, reaching ventral margin of interocular space (Fig. 12A). Clypeus elongate, 0.79 times as wide as long, with 1 dorsal seta (Fig. 12A). Palpus more lightly pigmented than head; third segment roughly cylindrical, about 1.5 length of fifth. Mandibles serrate, lacinia sclerotized with smooth margins. Antenna (Fig. 11B): pedicel dark brown, with at least one thicker, distinctive elongate dorsal seta; flagellum medium brown, with apex of flagellomeres I–III more lightly pigmented; flagellomeres I–III moderately elongate; XI–XIII elongate; flagellomere XIII with apical bifurcation. Sensilla coeloconica distribution: 1(II, X–XIII), 2(I). Cranial sensilla (Fig. 12A): Ocular row with 1 thick offset seta at ventral part; 1 more dorsal; 13 thick setae extending shortly beyond vertex; vertex with several setae. Subocular row inconspicuous. Postgenal row with 6 intermediate setae. With 2 ventromedial thick setae.

Thorax (Fig. 11D). Medium/dark brown. Prescutal suture not clearly visible. Anterior anepisternum divided longitudinally by sinuous suture. Posterior anepisternum undivided, dorsoventrally elongate. Sensilla (Fig. 12B): antepronotum with 3 intermediate ventral setae, 1 posterodorsal. Postpronotum with 1 dorsal thick seta, 2 small/ intermediate more ventrally. Scutum, prescutal area, with 4 thick, 4 intermediate setae scattered. Antealar area anterior portion with 2–3 thick setae dorsoventrally aligned, with 8 thick/intermediate setae more posteriorly, forming U-shape on ventral portion, with 5 intermediate setae surrounding. Supraalar area with 4 intermediate setae aligned longitudinally. Dorsocentral row, posterior part with cluster of 6 thick setae; about 12 thick, 12 intermediate setae completing the row. Scutellum with 14 thick setae. Posterior anepisternum without setae. Anepimeron with 6 slender setae.

Wings (Fig. 11E). Light brown, with three bands of darker scales: subbasal band on C, Sc, R 1, M; midlength band on all veins; subapical band on all veins. Non-marginal veins with broad scales. Apex of R 2 basal to apex of M 1. Halter lightly pigmented, distinctly lighter than scutellum. Wing length 1.24 mm. R 3 /R 1: 0.40. R 2+3 /R 2: 1.00.

Legs (Fig. 11C). Light/medium brown with knees pale; hind femur with apical 0.4 pale. Legs without scales. Midleg tarsomeres 1–3 with thick subapical setae. Tarsal claws on foreleg unequal; mid-, hind leg equal; apically inserted. Empodium slender, intermediate length, with 3 bifid branches (Fig. 12C). Apices of fore-, midtarsi not bilobed. Ta1/Ta2: 3.13. Ta3/Ta4: 0.75.

Abdomen (Fig. 11F). Uniformly medium brown.

Genitalia (Fig. 11F). Gonocoxite (Fig. 12D) brown at base, pale at apex, slender; without distinctively elongate spicules on anteromedial area; dorsomedial row well-defined proximally, with two distal setae similar in size to other surrounding setae. With 5 dorsal to dorsomedial setae, somewhat thicker than other setae on gonocoxite, strongly tapering distally. With 1 dorsomedial stout seta, tapering from base, located at 0.27 gonocoxite length from base; without sclerotized plate at base. Gonostylus slender, curved subapically; subbasal seta simple, elongate; anteriorly located. Apical seta or peg absent. Aedeagus elongate; fused subapically; with pointed apex (Fig. 12E).

Adult female: Unknown

Immatures: Unknown

Remarks. This species keys to couplet 5 - C. whartoni Vargas / C. belkini Borkent in Amaral et al. (2023). It can be distinguished from C. whartoni by having one ventral seta on the ocular row (two in C. whartoni); presence of a sensillum coeloconicum on flagellomere II, lacking on IX; posterior portion of dorsocentral row with six thick setae (four in C. whartoni, but this is a highly variable character in other species); subbasal band on wing not extending to posterior part; apical 0.4 of hind femur pale (hind femur completely pigmented in C. whartoni). Corethrella trivittata sp. nov. can be distinguished from C. belkini by lacking uniformly pigmented tarsi (in C. belkini, at least mid-, hind leg tarsomeres 2–4 with banding); abdominal segments VIII and IX equally pigmented (segment IX darker in C. belkini); gonostylus evenly tapering from base (with abrupt apical tapering in C. belkini); apical seta of gonostylus absent or very reduced (slender and elongate in C. belkini). The new species shares the distinctive wing pigmentation pattern of the quadrivittata species group, including one synapomorphy recognized by Borkent (2008), which is the presence of a subapical band of dark scales. Similarly to C. belkini, though, it does not have synapomorphies of the quadrivittata group, so its position in the phylogeny of the family remains somewhat uncertain.