Sitticine jumping spiders: phylogeny, classification, and chromosomes (Araneae, Salticidae, Sitticini).

The systematics of sitticine jumping spiders is reviewed, with a focus on the Palearctic and Nearctic regions, in order to revise their generic classification, clarify the species of one region (Canada), and study their chromosomes. A genome-wide molecular phylogeny of 23 sitticine species, using more than 700 loci from the arachnid Ultra-Conserved Element (UCE) probeset, confirms the Neotropical origins of sitticines, whose basal divergence separates the Aillutticina (a group of five Neotropical genera) from the subtribe Sitticina (five genera of Eurasia and the Americas). The phylogeny shows that most Eurasian sitticines form a relatively recent and rapid radiation, which we unite into the genus Simon, 1868, consisting of the subgenera Simon, 1901 (seven described species), (41 described species), and Prószyński, 2017 (one species). Five species of occur natively in North America, presumably through dispersals back from the Eurasian radiation, but an additional three species were more recently introduced from Eurasia. Peckham & Peckham, 1883 is considered to be a full synonym of C. L. Koch, 1837 (not a distinct subspecies). Emerton, 1891 is removed from synonymy and recognized as a senior synonym of Chamberlin & Ivie, 1944. Thus, the five native in North America are , , , , and . The other sitticines of Canada and the U.S.A. are placed in separate genera, all of which arose from a Neotropical radiation including Simon, 1901 and F.O.Pickard-Cambridge, 1901: (1) Banks, 1905 (, , ), (2) (), and (3) Prószyński, 2017 (). All Neotropical and Caribbean "" are transferred to either (12 species total) or (14 species). (three species) and are both removed from synonymy with ; the synonymy of Prószyński, 1971 with Caporiacco, 1947 is restored; Caporiacco, 1947 is synonymized with . Six generic names are newly synonymized with and one with . Two Neotropical species are described as new, and Forty-six new combinations are established and three are restored. Three species synonymies are restored, one is new, and two are rejected. Across this diversity of species is a striking diversification of chromosome complements, with X-autosome fusions occurring at least four times to produce neo-Y sex chromosome systems (XXY and XXXY), some of which ( and ) are sufficiently derived as to no longer preserve the simple traces of ancestral X material. The correlated distribution of neo-Y and a base autosome number of 28 suggests that neo-Y origins occurred preferentially in lineages with the presence of an extra pair of autosomes.