New stygofauna from Texas, USA: three new species of Parabathynellidae (Crustacea: Bathynellacea)

Abstract

Three new species of Parabathynellidae (Crustacea: Bathynellacea) are described using morphological and molecular data, and addi-tional populations identified as Texanobathynella cf. bowmani are placed within a molecular phylogeny for the group. The finding of Montanabathynella pecosensis sp. nov. entails a southern range expansion of over 1500 km for the genus, previously thought to be restricted to Montana, USA. Montanabathynella pecosensis sp. nov. displays a unique combination of morphological features, including eight main teeth on the labrum; four and six teeth on the pars incisiva and pars molaris of the mandible, respectively; eight teeth on the distal endite of MxI; epipod present on ThII and III; four teeth on the first segment of female ThVIII; and an unpro-nounced anal operculum. The other two new species described here belong to the genus Texanobathynella Delamare Deboutteville et al., 1975, previously consisting of only two species. Both species, Texanobathynella aaronswinki sp. nov and T. coloradoensis sp. nov., display combinations of morphological features distinct from the other two previously known species of the genus. Mitochondrial (COI) and nuclear (18S) markers support the validity of the new species and enable us to place them, along with T. cf. bowmani, within a larger phylogenetic framework of the Parabathynellidae.