Simulium (Psaroniocompsa) quadristrigatum Enderlein

(Figs. 15, 16, 42, 56, 70, 84)

Simulium quadristrigatum Enderlein, 1934a: 285 –286. HOLOTYPE Ψ, BRAZIL: Paraná; [Without date or collector’s name.] (NMHU) [Examined.]

Enderlein (1934a) described S. quadristrigatum based on a female collected in Paraná, Brazil. Coscarón (1983) examined the holotype, but because of its poor condition refrained from suggesting its conspecificity with S. delponteianum Wygodzinsky or S.

chaquense Coscarón, which have similar scutal patterns. He suggested that S. quadristrigatum was more closely related to S. delponteianum than to S. chaquense due to the matt appearance of the silver bands on the thorax and of the frons, and coloration of the legs and wing length. He also advocated dissection of the holotype to assess the taxonomic status of S. quadristrigatum .

The female of S. quadristrigatum in the NMHU has been examined and labelled as the holotype and the head, wings, legs, and abdomen dissected and mounted on a slide. Two females from Paraguay studied by Enderlein in 1936 were also examined. The thoraxes of these two specimens are slightly damaged, but the thoracic pattern and leg coloration are the same as in the S. quadristrigatum holotype. The head, wings, legs, and abdomen of these two specimens have been dissected and mounted on two separate slides. The holotype of S. quadristrigatum is covered in fungus and pinned through the middle of the scutum. Nevertheless, the scutal pattern is clear enough for it to be identified as belonging to a species in the amazonicum ­species group of the subgenus Psaroniocompsa Enderlein (Figs. 15, 16). Of the species in this group that have been recorded from Argentina, southern Brazil, and Paraguay, S. quadristrigatum is most closely related to S. chaquense Coscarón, S. cuneatum (Enderlein), and S. oyapockense Floch and Abonnenc (species complex) in having the scutal pattern, cibarium (Fig. 42), leg coloration, wing length and setation, and genitalia all similar (Figs. 56, 70, 84). The latter three species are most reliably separated by the number of pupal gill filaments. In S. oyapockense s.l. the pupa has six gill filaments, while S. chaquense has eight and S. cuneatum 10 filaments. Coscarón & Coscarón­Arias (2000) and Shelley et al. (1997, 2004; unpublished data) have shown that considerable variation occurs in the thoracic pattern of adults in species of the amazonicum group (e.g., S. oyapockense s.l. and S. amazonicum Goeldi) and the interpretation of this variation still requires considerable work.

We agree with Coscarón (1983, 1987) and maintain S. quadristrigatum as species inquirendae, due to the difficulty in separating the females of species in the amazonicum group that have not been reared. Coscarón (1987) placed S. quadristrigatum in the subgenus Cerqueirellum Py­Daniel, which is treated as a synonym of the subgenus Psaroniocompsa by Crosskey & Howard (2004) and followed in this paper.