A Multilevel Biodiversity Approach of the Hermit Crabs in the Iberian Peninsula and Ultraperipheral Territories

Abstract

The crustaceans of the superfamily Paguroidea constitute one of the most diverse groups within the Decapoda, exhibiting remarkable morphological and ecological diversity. Despite the relatively high number of described species worldwide, there are still many gaps in the knowledge of this group, particularly regarding genetic information. This study aims to update the geographic distribution information currently available for the hermit crab species in the Iberian Peninsula, Azores, Canary Islands, and Madeira, and generate a molecular database supported by morphological identification. The results are summarized in an updated list of Paguroidea recorded in the study area, which comprises a total of 55 species, representing a significant increase from previous compilations. Newly generated sequences, including those from the study area and closely related species from other areas, provide the first molecular information for 35 out of the 70 species analyzed. Phylogenetic analyses provide evidence of the species delimitation capabilities of molecular tools when reliable morphology-based information is available. Molecular analyses using two mitochondrial markers largely corresponded, supporting most traditionally established species and validating the morphological characters used for delimitation. Specifically, the COI gene showed better results and clearer topologies, suggesting greater utility for exploring species delimitation when using single-gene identification as a DNA barcode. Overall, the results of this long-term study will improve the capabilities for species delimitation, in addition to updating the composition and richness of species in the area.