Species-Specific Cuticular Phenotypes in Eutardigrada: A Morphometric Approach to Analyze the Variation of Star-Shaped Pores in Minibiotus Species

Abstract

The use and characterization of cuticular attributes for separation and description of species has been traditionally used in heterotardigrades; however, despite that eutardigrades show structures in the cuticle with this potential use, the intra and interspecific variation of these characters using multivariate analysis (e.g., PCA, CVA) had not been analyzed. In this present study, the shape and size of the star-shaped pores of four Minibiotus species were analyzed under univariate and multivariate morphometric analysis of six morphological characters. Our approach to evaluate the variation of pores indicate the presence of species-specific cuticular phenotypes among M. citlalium, M. constellatus, M. sidereus and M. pentannulatus. The morphological differences in these elements of sculpture allowed us to acknowledge their range of variation, as well as the identification of new potential characters o recognize these taxa, which are included in a taxonomic key to identify them together with M. eichhorni, M. pseudostellarus and M. vinciguerrae.