Molecular phylogeny of the tropical wandering spiders (Araneae, Ctenidae) and the evolution of eye conformation in the RTA clade

Abstract

Tropical wandering spiders (Ctenidae) are a diverse group of cursorial predators with its greatest species richness in the tropics. Traditionally, Ctenidae are diagnosed based on the presence of eight eyes arranged in three rows (a 2-4-2 pattern). We present a molecular phylogeny of Ctenidae, including for the first time representatives of all of its subfamilies. The molecular phylogeny was inferred using five nuclear (histone H3, 28S, 18S, Actin and ITS-2) and four mitochondrial (NADH, COI, 12S and 16S) markers. The final matrix includes 259 terminals, 103 of which belong to Ctenidae and represent 28 of the current 49 described genera. We estimated divergence times by including fossils as calibration points and biogeographic events, and used the phylogenetic hypothesis obtained to reconstruct the evolution of the eye conformation in the retrolateral tibial apophysis (RTA) clade. Ctenidae and its main lineages originated during the Paleocene-Eocene and have diversified in the tropics since then. However, in some analyses Ctenidae was recovered as polyphyletic as the genus Ancylometes Bertkau, 1880 was placed as sister to Oxyopidae. Except for Acantheinae, in which the type genus Acantheis Thorell, 1891 is placed inside Cteninae, the four recognized subfamilies of Ctenidae are monophyletic in most analyses. The ancestral reconstruction of the ocular conformation in the retrolateral tibial apophysis clade suggests that the ocular pattern of Ctenidae has evolved convergently seven times and that it has originated from ocular conformations of two rows of four eyes (4-4) and the ocular pattern of lycosids (4-2-2). We also synonymize the monotypic genus Parabatinga Polotov & Brescovit, 2009 with Centroctenus Mello-Leitão, 1929. We discuss some of the putative morphological synapomorphies of the main ctenid lineages within the phylogenetic framework offered by the molecular phylogenetic results of the study.

Advances in the reconstruction of the spider tree of life: A roadmap for spider systematics and comparative studies

“…Members of this family have a typical “ctenid eye pattern” of 2‐4‐2 eyes arranged in three rows of which anterior lateral eyes are smallest. The “ctenid eye pattern” has evolved convergently seven times in the RTA clade (Griswold, 1993; Hazzi & Hormiga, 2023). Most ctenids are ecribellate, but some genera such as Acanthoctenus have retained the cribellum (Griswold et al., 2005).…”

“…In the phylogeny of Piacentini and Ramírez (2019), Ancylometes was a sister terminal to Oxyopidae with poor support (39% posterior probability; see supplementary tree of Piacentini and Ramírez, 2019). The placement of Ancylometes varied across analyses in Hazzi & Hormiga (2023) including a placement as sister to Oxyopidae. The current taxonomic placement of Anyclometes within Ctenidae is unusual because it is the only group within ctenids that constructs a nursery web (Merret, 1988; Santos, 2007), a behaviour that is found primarily in Pisauridae.…”

“…However, only two outgroups ( Zoropsis and Tengella , both Zoropsidae) were used in the latter study, so its close relatives in the RTA clade could not be identified. Recently, Hazzi & Hormiga (2023) published the most comprehensive phylogeny of Ctenidae representing 28 of the current 49 described genera, using nine Sanger‐sequenced markers where the family was monophyletic. In our UCE phylogeny, Ctenidae was monophyletic (Fig.…”