Redescription of the hermit crab Diogenes pugilator (Decapoda: Anomura) reveals the existence of a species complex in the Atlanto-Mediterranean transition zone, resulting in the resurrection of D. curvimanus and the description of a new species

Abstract

Examination of material from the coasts of the Iberian Peninsula and nearby areas has revealed that more than one species is mixed under the name for the common diogenid hermit crab, Diogenes pugilator. In this study, three species are recognized, primarily on the basis of a combination of morphological characters and live colour patterns. Diogenes pugilator is redescribed on the basis of a neotype selected from near the supposed type locality, as well as specimens from other localities. Diogenes curvimanus is resurrected and the name attributed to a second species, whereas a third morphotype is described as a new species, Diogenes armatus sp. nov.. The last two species are also fully described and differentiating characters among the three species are discussed. Newly generated sequences from two mitochondrial genes and one nuclear gene, and comparative analyses with other available DNA sequences for the genus, are also included. The corresponding molecular phylogenies support the recognition of the three species and suggest the presence of additional unknown species in the D. pugilator species complex. All previous records of D. pugilator should be revised in the light of these new findings. Finally, a comprehensive identification key to the eastern Atlantic and western Mediterranean species of Diogenes is also provided.