Multivariate analysis: a useful tool in separating spermatophores produced by the diogenids Clibanarius erythropus, Diogenes pugilator and Calcinus tubularis (Decapoda, Anomura, Diogenidae)

Morphometric characteristics of the spermatophores of the Mediterranean hermit crabs, Clibanarius erythropus, Diogenes pugilator, and Calcinus tubularis have been determined. For the first time, the importance of a statistical approach using both univariate and multivariate techniques to study the morphometry of paguroid spermatophores is put forward. Discriminant factor analysis (DFA) allows correct classification of the spermatophores of these three species in 87% of the cases, although we did find a partial misclassification (20%) of D. pugilator spermatophores attributed to C. tubularis and of C. tubularis ones attributed to D. pugilator. Further analyses are necessary to assess whether the multivariate technique is also suitable to distinguish spermatophores produced by specimens belonging to other, congeneric species. It is recommended that multivariate analysis of spermatophores, together with univariate and classical morphological and ultrastructural analysis of the reproductive apparatus, be used to study phylogenetic relationships among the Paguroidea.