Corethrella (Corethrella) atricornis Borkent, 2008

Amaral, André P., Mariano, Rodolfo & Pinho, Luiz Carlos, 2023, Description of five new species of frog-biting midges (Diptera, Corethrellidae) from Brazil and examination of new morphological characters with utility for taxonomic and phylogenetic studies, European Journal of Taxonomy 874 (1), pp. 1-120 : 81-82

Corethrella (Corethrella) atricornis Borkent, 2008

Fig. 40 ; Appendix 1

Material examined

BRAZIL – Rio Grande do Sul State • 1 ♀, adult; Derrubadas, Parque Estadual do Turvo , Riacho Salto ; 27°08ʹ22ʺ S, 53°52ʹ52ʺW; 8 Oct. 2013; V. Caldart leg.; frog-call trap ( Scinax perereca ); CE-MHS • 1 ♀, adult; same collection data as for preceding, except 16 Dec. 2013; RB2N, control; CE-MHS .

Description

Female adult (n = 2)

HEAD. Sensilla ( Fig. 40A ): Ocular row with 1 thick offset seta on ventral portion, more dorsally with 17 setae shortly extending posteriorly. Subocular row well-defined, with 16 slender setae. Vertex with a few additional setae. Postgenal row with 9–10 intermediate and 10 slender setae ranging from mid-posteriorly to ventromedially. With 2 thick ventromedial setae.

THORAX. Sensilla ( Fig. 40B ): Antepronotum with 2–3 intermediate ventrolateral setae and 6–8 slender setae along anterolateral and ventrolateral margins. Postpronotum with 1 thick dorsal, 2 intermediate, and 2–3 more posterior slender setae. Scutum, prescutal area with 3 thick, 2 intermediate, and 2 slender setae loosely aligned vertically near prescutal suture; group of 6 intermediate and 6 slender setae more anteriorly, merging with anterior portion of dorsocentral row.Antealar area with 1 thick, 2 intermediate, and 3 slender setae anteriorly; group of about 7 thick/intermediate and 4 slender setae forming a U-shape more posteriorly; with 9 slender dorsal setae. Supraalar area with 3 thick anteroposteriorly aligned central setae, 9 slender setae surrounding. Dorsocentral row, posterior portion with 7 thick and 4 slender offset setae; 23 thick/intermediate and 36 slender setae completing row. Scutellum with 11–13 thick setae. Posterior anepisternum without setae. Anepimeron with 21 slender setae.

WING. R 3 /R 1: 0.51–0.58; R 2+3 /R 2: 0.57–0.71.

LEGS. Empodium ( Fig. 40C ) elongate, of intermediate thickness, with 5 branches. Ta1/Ta2: 2.76; Ta3/ Ta4: 1.10.

Distribution and biology

The studied specimens have previously been recorded by Caldart et al. (2016). They were captured using a frog-call trap playing the call of Physalaemus aff. gracilis and by a silent control trap. The traps were set near a pond in Turvo State Park, Rio Grande do Sul State, in an area of seasonal deciduous forest in southern Brazil, near the Argentinian border. The altitude was about 185 m a.s.l. This species is otherwise recorded from the type locality in the Atlantic forest of São Paulo State, at an altitude of 603 m a.s.l ( Borkent 2008).

Remarks

The two examined individuals differ slightly from the original species description with regard to the number of anepimeral and posterior dorsocentral setae, originally described as 15 and 5, respectively. One of them also had a long coronal suture. These differences, however, are considered intraspecific variation.

Figures

Fig. 40. Corethrella atricornis Borkent, 2008, female adult. A. Cranial setae, anterior and posterior views, and clypeus in anterior view. B. Thoracic setae, lateral view. C. Hind leg claw and empodium, lateral view.