Abnormal rostrum in Polycheles typhlops Heller, 1862 (Decapoda: Polychelidae) from the Central Western Mediterranean

Anomalies of the number of rostral spines have been recorded in blind lobsters, Polycheles typhlops, caught in Sardinian waters (Central Western Mediterranean). The abnormal specimens, 66 out a total of 789 individuals analysed, showed all the morphometric characteristics of P. typhlops except for the unusual presence of two rostral spines instead of the canonical one. The analysis of partial nucleotide sequences of the mitochondrial cytochrome oxidase subunit I gene (COI) showed that the individuals with two spines were not genetically different from the normal specimens of P. typhlops, while both were quite dissimilar from the other Mediterranean species, P. sculptus. Our results suggest the need of an update of the morphological classification guides for this family combined with a wider genetic study.