Phylogeny of three species groups of Rhinocricus Karsch, 1881 based on morphological characters (Diplopoda, Spirobolida, Rhinocricidae)

Abstract

Rhinocricus Karsch, 1881 has 207 species occurring mainly in the Americas, and more than 60 of them were described from Brazil. The genus was proposed based on the presence of dorsal scobinae on the prozonites. The present study evaluates the monophyly of three species groups previously proposed in Rhinocricus. We evaluated 39 morphological characters and included 30 species as terminal taxa, 9 of which are outgroups. We performed a parsimony analysis under implied weighting in TNT 1.5, obtaining the same most parsimonious tree topology with three optimal K values (5.992, 7.309, and 9.105). None of the three previously proposed species groups of Rhinocricus was recovered monophyletic. Rhinocricus (Erythocricus) sanguineostriatus Schubart, 1962 was recovered sister to all other species, and Argentocricus Verhoeff, 1941 resulted paraphyletic. The diagnostic morphological characters traditionally used to separate species groups, subgenera, and genera were not recovered as synapomorphies. Further investigation including a broader species sample is needed to establish robust relationship hypotheses between Argentocricus and the remainder species of Rhinocricus, thus identifying monophyletic groups in the genus and their synapomorphies.