Species differentiation of scutacarid mites (Heterostigmatina) using multivariate morphometric methods

The genera of the mite family Scutacaridae (Heterostigmatina) can be easily distinguished by certain qualitative traits, whereas the species of these genera are lacking conspicuous distinctive features and thus, species descriptions are often based on quantitative characters. However, the intraspecific variability of these traits can be pronounced and the applicability of multivariate morphometric methods for species differentiation has not been studied so far. In the present study, four members of the genus Scutacarus, referred to as the acarorum species-complex, were analysed using traditional and geometric morphometric methods. The results showed that multivariate morphometric methods are perfectly suitable for differentiating even between morphologically similar scutacarid species, with traditional morphometrics performing better than geometric morphometrics. Despite their morphological similarity, morphometric analyses support the species status of the four members of the species-complex.