Molecular analysis of the taxonomic and distributional status for the hermit crab genera Loxopagurus Forest, 1964 and Isocheles Stimpson, 1858 (Decapoda, Anomura, Diogenidae)

Recent studies of adult and larval morphology have revealed characters that could justify reassignment of Loxopagurus loxochelis to the genus Isocheles. Current taxonomy of these two similar genera is based only on adult morphology and disregards morphological characters of the first zoeal stage. There has been no previous attempt to resolve evolutionary relationships among the species of these two genera using molecular tools. Herein, we include these species in a phylogenetic analysis of selected anomuran decapods based on sequences of the 16S ribosomal gene. Our present molecular analysis does not support reassignment of Loxopagurus loxochelis to the genus Isocheles. In contradiction to previous suggestions, we show that L. loxochelis and I. sawayai are indeed different species. We also corroborate the previous report of I. sawayai in Venezuelan waters.