We review the systematics of sitticine jumping spiders, 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 new subtribe Aillutticina (a group of 5 Neotropical genera) from the subtribe Sitticina (5 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 Attulus Simon 1868, consisting of the subgenera Sitticus Simon, 1901 (7 described species), Attulus (41 described species), and Sittilong Prószyński, 2017 (one species). Five species of Attulus occur natively in North America, presumably through dispersals back from the Eurasian radiation, but an additional three species were more recently introduced from Eurasia. We consider Attus palustris Peckham and Peckham, 1883 to be a full synonym of Euophrys floricola C. L. Koch, 1837 (not a distinct subspecies). We remove Attus sylvestris Emerton, 1891 from synonymy and recognize it as a senior synonym of Sitticus magnus Chamberlin & Ivie, 1944. Thus, the five native Attulus in North America are Attulus floricola, A. sylvestris, A. cutleri, A. striatus, and A. finschi. The other sitticines of Canada and the U.S.A. are placed in separate genera, all of which arose from a Neotropical radiation including Jollas Simon, 1901 and Tomis F.O.Pickard-Cambridge, 1901: (1) Attinella Banks, 1905 (A. dorsata, A. concolor, A. juniperi), (2) Tomis (T. welchi), and (3) Sittisax Prószyński, 2017 (S. ranieri). All Neotropical and Caribbean "Sitticus" are transferred to either Jollas (12 species total) or Tomis (14 species). Attinella (3 species) and Tomis are both removed from synonymy with Sitticus; the synonymy of Sitticus cabellensis Prószyński, 1971 with Pseudattulus kratochvili Caporiacco, 1947 is restored; Pseudattulus Caporiacco, 1947 is synonymized with Tomis. Six generic names are newly synonymized with Attulus and one with Attinella. We describe two Neotropical species as new, Jollas cupreus sp. nov. and Tomis manabita sp. nov. Forty-four new combinations are established and several are restored. Four 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 4 times to produce neo-Y sex chromosome systems (X1X2Y and X1X2X3Y), some of which (Sittisax ranieri and S. saxicola) 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.

Most files are Ultra Conserved Element sequence capture data using the Arachnid 1.1 probeset. See paper for details of filtering and assembly. One file is for CO1 only, mixing Genback downloaded sequences with sequences recovered as bycatch from the UCE data. One file is with chromosome data.

The chromosome data file, when opened with Mesquite, will show the tree with character traced.