North American Ninetinae: the genera Pholcophora and Tolteca
(submitted; together with G. Meng, A. Valdez-Mondragón, J. Král, I.M. Ávila Herrera, and L.S. Carvalho)
Our second major publication in a current project on the subfamily Ninetinae, we deal with the North American-Caribbean genera Pholcophora and Tolteca. We present the first comprehensive revisions of the two genera, with descriptions of seven new species we collected in Mexico in 2019, and extensive SEM data. We add new CO1 sequences of nine species to the matrix of Eberle et al. (2018) and use these for a preliminary analysis of relationships. We recover a North American-Caribbean clade including ‘true’ (mainland) Pholcophora, Tolteca (Mexico), and a Caribbean clade consisting of the genus Papiamenta Huber, 2000 (Curaçao) and Caribbean ‘Pholcophora’.

In a previous study we have shown that the karyotype Pholcophora americana (2n♂ = 29, X1X2Y) is close to the supposed ancestral karyotype of pholcid spiders (Ávila Herrera et al., 2021). First karyotype data for Tolteca (2n♂ = 13, X1X2Y and 15, X1X2Y, respectively) reveal a strong reduction of the number of chromosome pairs within the North American-Caribbean clade. In addition, we document considerable karyotype differentiation among congeners in Tolteca. This agrees with considerable CO1 divergence among Tolteca species but contrasts with very inconspicuous morphological divergence.

Environmental niche analyses show that the widespread P. americana Banks, 1896 (western USA, SW Canada) occupies a very different niche than its Mexican congeners and other close relatives. Caribbean taxa also have a low niche overlap with ‘true’ Pholcophora and Tolteca, supporting the idea that Caribbean ‘Pholcophora’ are taxonomically misplaced.