Phylogenetic analysis and revision of the linyphiid spider genus Solenysa (Araneae: Linyphiidae: Erigoninae)

Abstract

In this paper we carry out a taxonomic revision and phylogenetic analysis of the linyphiid spider genus Solenysa Simon, 1894. A total of 12 species is treated here, including five new species collected from China and Japan: Solenysa akihisai Tu sp. nov., Solenysa lanyuensis Tu sp. nov., Solenysa retractilis Tu sp. nov., Solenysa tianmushana Tu sp. nov., and Solenysa yangmingshana Tu sp. nov. Solenysa circularis Gao, Zhu & Sha, 1993 is a junior synonym of Solenysa protrudens Gao, Zhu & Sha, 1993. We have assembled two different character matrices to reconstruct the phylogenetic relationships of Solenysa. In the first matrix (Matrix 1), five representative species of Solenysa were added to the morphological dataset of Miller & Hormiga to test the monophyly of the genus and its placement within Linyphiidae. The genitalic structures and somatic morphology of Solenysa were studied by means of scanning electron microscopy for the first time. To infer the species-level phylogenetic relationships of Solenysa we produced a second matrix (Matrix 2) that includes all 12 Solenysa species and six outgroup species chosen from the results of the analysis of the first matrix. The two most parsimonious trees from the analysis of Matrix 1 support the monophyly of Solenysa and its placement within the 'Distal Erigonines' clade. The single most parsimonious tree resulting from the analysis of the second matrix suggests that the Solenysa clade includes four monophyletic groups, each group represented by a distinct genitalic pattern. The morphology of Solenysa, both somatic and genitalic, is highly autapomorphic.

Resolving the phylogeny of a speciose spider group, the family Linyphiidae (Araneae)

“…Gaps in taxon sampling result in gaps of 81 associated character transformation, especially for lineages with 82 long history and many accumulated morphological changes (e.g. 83 Arnedo et al, 2009;Tu and Hormiga, 2011). Insufficient sampling 84 may conceal homoplastic changes (Heath et al, 2008; 85 Huelsenbeck and Lander, 2003).…”

A review of Solenysa spiders from Japan (Araneae, Linyphiidae), with a comment on the type species S. mellotteei Simon, 1894

“…Other Solenysa species were described successively from other places in Japan, the Chinese mainland, Taiwan, and the Korean Peninsula (see review by Tu and Li 2006). In recent studies, several new species were sorted from the Solenysa collections deposited in the Department of Zoology, National Museum of Nature and Science (ex National Science Museum, Tokyo), Japan (Tu et al 2007, Tu and Hormiga 2011, Ono 2011). Prior to this study, there were five Solenysa species reported from Japan: Solenysa mellotteei Simon, 1894 (type locality: Yokohama, Kanagawa Prefecture), Solenysa akihisai Tu, 2011 (type locality: Hachioji, Tokyo), Solenysa ogatai Ono, 2011 (type locality: Okazaki-shi, Aichi Prefecture), Solenysa partibilis Tu, Ono & Li, 2007 (type locality: Mt.…”

“…Ibuki-yama, Shiga Prefecture) and Solenysa reflexilis Tu, Ono & Li, 2007 (type locality: Itsuki-mura, Kumamoto Prefecture). According to results of a phylogenetic analysis based on morphological data, the twelve known Solenysa species were divided into four groups, and the four species from Japan share a complex of genital characters, forming the Solenysa mellotteei group (Tu and Hormiga 2011). …”

“…7). Small in body size, similar in somatic features and genital morphology, it is difficult to distinguish them from each other without examining their genitalia in detail (Tu and Hormiga 2011). Consequently, all Solenysa spiders collected from the islands of Japan have long been identified as Solenysa mellotteei (Oi 1960, Yaginuma 1986, Irie and Saito 1987, Chikuni 1989, Lee et al 2004, Tu and Li 2006).…”

“…Consequently, all Solenysa spiders collected from the islands of Japan have long been identified as Solenysa mellotteei (Oi 1960, Yaginuma 1986, Irie and Saito 1987, Chikuni 1989, Lee et al 2004, Tu and Li 2006). Redescriptions for the species currently bearing the generotype name, Solenysa mellotteei , in reviews of Solenysa were not based on the type material (Tu and Li 2006, Tu and Hormiga 2011) and the species are different from those collected from the places more adjacent to the inferred type locality (Ono 2011). It is necessary to make a review to distinguish the species of the Solenysa mellotteei group and to establish the identity of the generotype Solenysa mellotteei .…”