Psilochorus Simon, 1893

Huber, Bernhard A. & Carvalho, Leonardo S., 2019, Filling the gaps: descriptions of unnamed species included in the latest molecular phylogeny of Pholcidae (Araneae), Zootaxa 4546 (1), pp. 1-96 : 64

Psilochorus Simon, 1893

Psilochorus Simon, 1893: 482 ; type species by original designation: Theridion pullulum Hentz, 1850 .

Psilochorus — Gertsch 1971: 72. Huber 1998: 595, fig. 10. Slowik 2009: 3 .

Notes. With the transfer of the New Guinean species Psilochorus nigromaculatus Kulczyński, 1911 to Arnapa gen. n. (see above), Psilochorus is finally a pure New World genus. However, Psilochorus continues to be among the very few pholcid genera with autochthonous representatives in both North and South America. The type species is North American; North American taxa have been revised and diagnosed recently ( Slowik 2009) but that study excluded the rich Mexican fauna. The generic assignment of South American representatives has long been doubted ( Huber 1998). The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) recovered North American and South American clades but did neither support nor contradict a sister group relationship between them. Morphological data are equally ambiguous with respect to the sister groups of the two clades. Consequently, there is currently no clear justification for splitting the genus.

Seven nominal species from South America are currently assigned to Psilochorus . Of these, the identity of five is dubious: P. sectus Mello-Leitão, 1939 ; P. taperae Mello-Leitão, 1929 ; P. bruneocyaneus Mello-Leitão, 1941 ; P. marcuzii Caporiacco, 1955 ; P. minimus Schmidt, 1956 . Of the other two species ( P. itaguyrussu Huber et al., 2005 and P. ybytyriguara Huber et al., 2005 ) only the males are known. They were assigned to Psilochorus based on the striking similarity of the male pedipalps, but the cladistic analysis of morphological data did not convincingly support this solution (Huber et al. 2005).

The recent molecular phylogeny of Pholcidae ( Eberle et al. 2018) included three South American species tentatively assigned to Psilochorus : P. itaguyrussu and two undescribed species. Of the latter, one is known from females only and thus not formally described here (its female genitalia are shown in Figs 252–254 ). The second is represented by both males and females and formally described below. Numerous further species are known to exist in the Atlantic Forest of Brazil ( Fig. 348 ). We suspect that this clade is in fact restricted to the Atlantic Forest and that most or all of the five dubious South American species above are misplaced.

Figures

FIGURE 348. Known distribution of Psilochorus in the Atlantic Forest of Brazil. Red marks: undescribed species (L.S. Carvalho, B.A. Huber, unpubl. data). Five further South American nominal species are currently assigned to Psilochorus, but their identities and affinities are dubious (see text).

FIGURES 252–263. Epigyna (ventral views), and cleared female genitalia (ventral and dorsal views) of four undescribed Brazilian species of Psilochorus,. 252–254. “Br10-36” from Vargem Alta, Espírito Santo. 255–257. “Br11-147” from Parque Nacional do Pau Brasil, Bahia. 258–260. “Br11-81” from Reserva Biológica de Una, Bahia. 261–263. “Br15-173” from Santa Terezinha, Bahia. pp, pore plates. At various scales.