A phylogenetic review of the genus Hexabathynella Schminke, 1972 (Crustacea, Malacostraca, Bathynellacea): with a description of four new species

Abstract

The genus Hexabathynella (Crustacea, Malacostraca, Bathynellacea) is revised in the sense of the phylogenetic systematics and four new species are described from South Africa (H. monoaethetasca sp. nov. and H. africana sp. nov.) and America (H. schrieveri sp. nov. and H. virginiae sp. nov.). A comparative analysis of all observable outer structures distributed in 18 known and four new species resulted in a re-evaluation of 18 characters and character states. The phylogenetic analysis using the program PAUP yielded one most-parsimonious tree, which suggests the grouping of (H. decora ((H. halophila + H. aotearoae) + (H. pauliani (H. monoaethetasca +H. africana)))) + (H. knoepffleri (H. nicoleiana (H. hebrica, H. tenera, H. longiappendiculata, H. breviappendiculata, H. nestica) + H. virginiae ((H. minuta (H. valdecasasi+H. otayana)) + (H. hessleri+H. muliebris))) + H. paranaensis (H. szidati+H. schrieveri)). The tree is 57 steps long and has a consistency index of 0.6140, a retention index of 0.7982 and a rescaled consistency index of 0.4901. The result does not agree with the previous analyses on the genus. In terms of sampling and coding, the characters used in the previous study are critically assessed. (c) 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 147, 71-96.