Corethrella compacta Amaral & Pinho, 2025

Corethrella compacta Amaral & Pinho sp. nov.

urn:lsid:zoobank.org:act:

Figs. 1–2 View FIGURE 1 View FIGURE 2

Type material. Holotype: ♀ adult: COLOMBIA, Antioquia, San Roque, vereda Guacas Abajo, quebrada El Topacio , 880–1100m, bosque fragmentado, 6°29'27"N, 74°57'5"W. Pitfall baited with human feces. 4– 7. IV, 2013. A. Vélez-Bravo leg. (Colo19) ( CEUA) GoogleMaps . Paratypes: ♀ adult: as holotype, except: (Colo17) ( USNM) ; ♀ adult: as holotype, except: (Colo18) ( CEMHS) .

Etymology. The specific name is a reference to the very short proximal flagellomeres.

Diagnosis. Adult female. Only extant species of Corethrella with flagellomeres I–III globular, IV–XIII very elongated ( Fig. 1A View FIGURE 1 ); wings, legs with broad scales ( Fig. 1B, D View FIGURE 1 ).

Description

Adult female (n = 3).

Head ( Fig. 1A View FIGURE 1 ). Dark brown. Outline of head in anterior view laterally elongate; head W/L 1.34–1.39. Coronal suture complete, reaching ventral margin of interocular space ( Fig. 2A View FIGURE 2 ). Clypeus somewhat elongate, 0.76–0.88 times as wide as long, with 14–18 dorsal setae. Palpus more lightly pigmented than head; third segment swollen at midlength, about 2 times length of fifth. Mandibles serrate, lacinia sclerotized with smooth margins. Antenna ( Fig. 1A View FIGURE 1 ): pedicel dark brown, with at least one thicker, distinctive, elongate dorsal seta; flagellum more lightly pigmented than head; flagellomeres I–III very short; XI–XIII elongate; flagellomere XIII with apical bifurcation. Sensilla coeloconica distribution: 1(XII–XIII), 2 (II, VIII–XI), 3([IX]), 4(I). Cranial sensilla ( Fig. 2A View FIGURE 2 ): Ocular row with 2 thick offset setae at ventral part; 9–10 thick setae extending shortly beyond vertex; vertex without setae; few slender setae on frons. Subocular row inconspicuous. Postgenal row with 9–10 slender/intermediate setae. With 1 ventromedial thick seta.

Thorax ( Fig. 1C View FIGURE 1 ). Medium/dark brown. Prescutal suture short, ending halfway towards dorsocentral row of setae ( Fig. 2B View FIGURE 2 ). Anterior anepisternum divided longitudinally by sinuous suture. Posterior anepisternum divided by a diagonal suture, inferior portion triangular with anterodorsal margin thick. Sensilla ( Fig. 2B View FIGURE 2 ): Antepronotum with about 4 slender setae anteriorly. Postpronotum with 1 thick dorsal seta, 2 slender more posterior. Scutum, prescutal area with 2 thick setae anteroventrally and group of 3 thick setae near prescutal suture. Antealar area with cluster of 11–12 thick/intermediate setae centrally located. Supraalar area with 2–3 thick setae anteroposteriorly aligned, 4–6 intermediate/slender setae surrounding. Dorsocentral row, posterior part with 9–12 thick offset, longitudinally aligned setae; about 16 thick setae, 18 intermediates completing the row. Scutellum with 10 thick setae. Posterior anepisternum with 1–2 slender setae at dorsal part. Anepimeron without setae.

Wings ( Fig. 1D View FIGURE 1 ). Light brown, without any pattern of pigmentation. Non-marginal veins with broad scales. Apex of R 2 equal to apex of M 1. Halter as dark as scutellum. Wing length 1.46–1.51 mm. R 3 /R 1: 0.66–0.68. R 2+3 /R 2: 0.31–0.36.

Legs ( Fig. 1B View FIGURE 1 ). Light brown, base of midfemur somewhat darker; hind tibia uniformly pigmented. Femora, tibiae, tarsi with broad scales. Midleg tarsomeres 1–3 with thick subapical setae. Tarsal claws equal; apically inserted. Empodium with intermediate thickness; intermediate length; with 6 bifid branches ( Fig. 2C View FIGURE 2 ). Ta1/Ta2: 2.36–2.48. Ta3/Ta4: 1.29–1.4.

Abdomen ( Fig. 1E View FIGURE 1 ). Medium/dark brown, with cercus more lightly pigmented.

Adult male: Unknown

Immatures: Unknown

Remarks. This species keys to the couplet 18 - C. ramentum Borkent, 2008 ( peruviana group) in Amaral et al. (2023). Corethrella compacta sp. nov. belongs within the peruviana species group. The synapomorphic states shared with the other species in the group, as recognized by Borkent (2008), are the following: wing without pattern of pigmentation; ventral portion of ocular row with two setae; anepimeron without setae; femora with scales; and base of midfemur more darkly pigmented. Moreover, as discussed by Amaral et al. (2023), the arrangement of the scutellar setae on the antealar area is unique for the species in the peruviana group. Within the peruviana group, only C. truncata Borkent has very short flagellomeres I–III, however unlike C. compacta sp. nov., which has an elongate flagellomere IV, C. truncata also has a very short flagellomere IV. The two species can also be distinguished by the distribution of sensilla coeloconica on the flagellum; the presence of posterior anepisternal setae; the scales on the legs, which are broad in C. compacta sp. nov. and narrow in C. truncata ( Borkent 2008:381, Fig. 74A); and the pattern of pigmentation of legs.