Molecular Identification Reveals Hidden Distribution Patterns in Cognettia (Enchytraeidae)

The study of Palaearctic enchytraeid taxonomic richness revealed the limitations of applying morphological identification methods to certain species of the genus Cognettia. The use of molecular approaches enabled the identification of individuals belonging to C. chlorophila among immature and fragmented enchytraeids that had initially been identified morphologically as C. sphagnetorum s.l. These findings substantially extend the known distribution range of C. chlorophila eastward. Reliable distribution data for C. chlorophila and C. sphagnetorum s.s., obtained through genetic analysis, complement existing evidence of their coexistence in shared habitats and highlight questions concerning their biotopic preferences. It is hypothesized that the relatively low level of genetic diversity in these species is associated with potential postglacial dispersal routes of C. sphagnetorum s.l. from Scandinavian refugia and with species-specific biological characteristics.