The spider genus Stictonanus Millidge, 1991 in the Juan Fernandez Archipelago (Araneae, Linyphiidae): systematics and biogeography

 

The spider genus Stictonanus Millidge, 1991 in the Juan Fernandez Archipelago (Araneae, Linyphiidae): systematics and biogeography 

We studied the systematics of the Juan Fernandez linyphiid species originally classified in the genus Juanfernandezia Koçak & Kemal, 2008. In an earlier study, we had hypothesized that the two Juanfernandezia species, each endemic to a single island, form a clade that was sister to the southern South American genus Notholepthyphantes Millidge, 1985. We have carried out a multi-locus phylogenetic analysis to infer the relationships of Juanfernandezia based on an extended taxon sampling. Our study shows that Juanfernandezia is sister to the South American genus Stictonanus Millidge, 1991, which until recently remained poorly known. The striking similarity of the somatic and genitalic morphology of these two genera suggest that the clade is better classified as a single genus, with Stictonanus being the oldest available generic name for this lineage. Stictonanus, circumscribed now to include five species, is sister to a lineage composed of two small genera, Notholepthyphantes and Falklandoglenes Usher, 1986. Stictonanus fernandezi (Berland, 1924) comb. nov. and Stictonanus paolae Hormiga & Arnedo, sp. nov., both from the Juan Fernandez Islands, are described and illustrated. The type species of the genus, Stictonanus paucus Millidge, 1991, and the second continental species, S. exiguus Millidge, 1991, are here redescribed and illustrated (the male of S. exiguus is described here for the first time). We further infer a time calibrated tree to discuss the biogeographic history of Stictonanus.

Hormiga G, Lavery AH, Arnedo MA. (2025) The spider genus Stictonanus Millidge, 1991 in the Juan Fernandez Archipelago (Araneae, Linyphiidae): systematics and biogeography. Invertebrate Systematics 39, IS25046. https://doi.org/10.1071/IS25046