Systematics of Nearctic Cybaeus (Araneae:Cybaeidae)

Abstract

Spiders in the genus Cybaeus L. Koch (Araneae : Dictynoidea : Cybaeidae) are common forest-floor inhabitants in western North America and Japan. Here we establish an initial phylogenetic framework for North American Cybaeus. Morphological details for eight proposed species groups are given, and these results, combined with molecular analyses of one nuclear and one mitochondrial gene for six of the eight species groups, suggest that North American Cybaeus species are contained in two broad clades, one Holarctic and one Nearctic (primarily Californian). The Holarctic clade contains the tetricus and angustiarum species groups, which contain mostly widely distributed species. The Californian clade includes the adenes, aspenicolens, consocius, devius, septatus and tardatus species groups, all of which have very restricted ranges. The genus Cybaeus and the Palaearctic species C. tetricus (C.L. Koch) (type species of the genus) and C. angustiarum L. Koch are redescribed and illustrated. A key to species groups is provided. Nine new species endemic to the western Nearctic and included in the molecular analyses are described and illustrated: C. paralypropriapus Bennett, sp. nov. and C. waynei Bennett, sp. nov. (tetricus group); C. sanbruno Bennett, sp. nov. (adenes group); C. thermydrinos Bennett, sp. nov. (aspenicolens group); C. penedentatus Bennett, sp. nov. and C. vulpinus Bennett, sp. nov. (consocius group); C. chauliodous Bennett, sp. nov. and C. somesbar Bennett, sp. nov. (septatus group); and C. gidneyi Bennett, sp. nov. (unplaced).

Pervasive associations between Cybaeus spiders and the bacterial symbiont Cardinium

“…(The lack of concordance between Wolbachia and Cardinium infection also argues against hybridization followed by introgression as an explanation for Cardinium haplotype infection patterns; nor does phylogenetic analysis of host mitochondrial versus nuclear DNA suggest hybridization (Copley et al, 2009).) Comparisons of wsp and ftsZ confirm that wsp (and Wolbachia) exhibits extremely high rates of recombination; wsp is much more variable and completely discordant with ftsZ.…”

“…Collection locales are also shown. Cybaeus phylogeny is based on histone H3 sequence, and Ãà and à signify >80% and >60% bootstrap support, respectively (Copley et al, 2009). We were unable to sequence gyrB from the Cardinium infecting C. waynei and C. nana.…”

“…However, the fact that species collected from the same or nearby locations harbor the same Cardinium haplotypes supports the possibility that horizontal transmission in Cybaeus-infecting Cardinium may be significantly higher than in other heritable symbionts. (The Cardinium infection in C. signifer is particularly interesting, as this spider is quite divergent [Copley et al, 2009] from species that harbor the same Cardinium haplotype). Even with appreciable levels of horizontal transmission, it is likely that the strains identified in this study are specialized on cybaeid spiders.…”

“…Spider histone sequences were obtained from our taxonomic and phylogenetic study of Nearctic Cybaeus (Copley et al, 2009). …”

Taxonomic notes onCybaeus vignaiBrignoli, 1977 (Araneae, Cybaeidae) andDysdera cribrataSimon, 1882 (Araneae, Dysderidae) from the Italian Maritime Alps

“…The nomenclature of morphological structures follows Copley et al (2009) for Cybaeus vignai and Deeleman- Reinhold & Deeleman (1988) for Dysdera cribrata.…”