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

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.

Methods
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.

本研究针对西蒂蛛亚科跳蛛（sitticine jumping spiders）的分类系统学展开综述，重点聚焦古北界（Palearctic）与新北界（Nearctic）区域，旨在修订其属级分类框架、澄清加拿大区域的物种类群，并开展染色体相关研究。本研究基于蛛形纲超保守元件（Ultra-Conserved Element, UCE）探针组的700余个基因座，对23种西蒂蛛亚科蜘蛛开展全基因组分子系统发育分析，结果证实西蒂蛛亚科起源于新热带界（Neotropical）；其基部分化事件将新定义的艾卢蒂蒂蛛亚族（Aillutticina，包含5个新热带界属级类群）与西蒂蛛亚族（Sitticina，包含欧亚大陆与美洲的5个属）相互分离。系统发育分析结果显示，绝大多数欧亚西蒂蛛类群形成了一个相对晚近的快速适应辐射类群，本研究将其归并入阿吐蛛属（Attulus Simon 1868），该属包含3个亚属：西蒂蛛亚属（Sitticus Simon, 1901，7个已描述物种）、阿吐蛛亚属（Attulus，41个已描述物种）以及Sittilong Prószyński, 2017（1个物种）。有5种阿吐蛛属物种原生分布于北美地区，推测其源自欧亚类群的二次扩散；另有3个物种则是近期从欧亚大陆引入的外来类群。本研究认定Attus palustris Peckham & Peckham, 1883为Euophrys floricola C. L. Koch, 1837的完全同物异名（并非独立亚种）。本研究将Attus sylvestris Emerton, 1891从同物异名列表中移除，并认定其为Sitticus magnus Chamberlin & Ivie, 1944的优先同物异名。据此，北美原生的5种阿吐蛛属物种分别为Attulus floricola、A. sylvestris、A. cutleri、A. striatus以及A. finschi。加拿大与美国的其余西蒂蛛类群被归入不同的属级类群，所有类群均源自以Jollas Simon, 1901和Tomis F.O.Pickard-Cambridge, 1901为代表的新热带界适应辐射支系：(1) Attinella Banks, 1905（包含A. dorsata、A. concolor、A. juniperi）、(2) Tomis（包含T. welchi）以及(3) Sittisax Prószyński, 2017（包含S. ranieri）。所有新热带界与加勒比海地区原归入“Sitticus”的类群均被重新划归至Jollas（总计12个物种）或Tomis（总计14个物种）。Attinella（3个物种）与Tomis均被从Sitticus的同物异名列表中移除；本研究恢复Sitticus cabellensis Prószyński, 1971与Pseudattulus kratochvili Caporiacco, 1947之间的同物异名关系，并将Pseudattulus Caporiacco, 1947归为Tomis的同物异名。另有6个属级名称被新确立为阿吐蛛属的同物异名，1个属级名称被确立为Attinella的同物异名。本研究描述了2个新的新热带界物种：Jollas cupreus sp. nov.与Tomis manabita sp. nov.；共确立44个新组合，并恢复了部分原有组合；此外恢复了4个物种同物异名关系，新增1个物种同物异名关系，驳回2个物种同物异名关系。该类群的物种多样性伴随显著的染色体组型分化：X染色体与常染色体融合事件至少发生4次，由此形成新Y染色体性别决定系统（X1X2Y与X1X2X3Y）；其中部分类群（如Sittisax ranieri与S. saxicola）的分化程度极高，已不再保留祖先X染色体的原始痕迹。新Y染色体系统与28条常染色体的基础染色体数呈现显著相关性，提示新Y染色体的起源更偏好发生在额外携带一对常染色体的支系中。

## 研究方法
绝大多数数据文件为基于蛛形纲1.1（Arachnid 1.1）探针组的超保守元件序列捕获数据，序列过滤与组装的详细方法参见论文原文。另有1份文件仅包含CO1基因序列，其数据由从GenBank下载的序列与从UCE数据中附带获取的序列混合而成；还有1份文件包含染色体相关数据。