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

Abstract

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 thenew subtribeAillutticina (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 genusAttulusSimon, 1868, consisting of the subgeneraSitticusSimon, 1901 (seven described species),Attulus(41 described species), andSittilongPrószyński, 2017 (one species). Five species ofAttulusoccur natively in North America, presumably through dispersals back from the Eurasian radiation, but an additional three species were more recently introduced from Eurasia.Attus palustrisPeckham & Peckham, 1883 is considered to be a full synonym ofEuophrys floricolaC. L. Koch, 1837 (not a distinct subspecies).Attus sylvestrisEmerton, 1891 is removed from synonymy and recognized as a senior synonym ofSitticus magnusChamberlin & Ivie, 1944. Thus, the five nativeAttulusin North America areAttulus floricola,A. sylvestris,A. cutleri,A. striatus, andA. finschi. The other sitticines of Canada and the U.S.A. are placed in separate genera, all of which arose from a Neotropical radiation includingJollasSimon, 1901 andTomisF.O.Pickard-Cambridge, 1901: (1)AttinellaBanks, 1905 (A. dorsata,A. concolor,A. juniperi), (2)Tomis(T. welchi), and (3)SittisaxPrószyński, 2017 (S. ranieri). All Neotropical and Caribbean “Sitticus” are transferred to eitherJollas(12 species total) orTomis(14 species).Attinella(three species) andTomisare both removed from synonymy withSitticus; the synonymy ofSitticus cabellensisPrószyński, 1971 withPseudattulus kratochviliCaporiacco, 1947 is restored;PseudattulusCaporiacco, 1947 is synonymized withTomis. Six generic names are newly synonymized withAttulusand one withAttinella. Two Neotropical species are described as new,Jollas cupreussp. nov.andTomis manabitasp. nov.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 (X1X2Y and X1X2X3Y), some of which (Sittisax ranieriandS. 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.