Patterns of Cryptic Diversity and Phylogeography in Four Freshwater Copepod Crustaceans in European Lakes

Comparative phylogeography has become a powerful approach in exploring hidden or cryptic diversity within widespread species and understanding how historical biogeographical factors shape the modern patterns of their distribution. Most comparative phylogeographic studies so far focus on terrestrial vertebrate taxa, while aquatic invertebrates (and especially freshwater invertebrates) remain unstudied. In this article, we explore compare molecular structure four copepod crustaceans European water bodies: harpacticoids Attheyella crassa, Canthocamptus staphylinus Nitokra hibernica, cyclopoid Eucyclops serrulatus, using sequence data from mtDNA COI nuclear ITS/18S rRNA genes. The three taxa A. C. E. serrulatus each consist deeply diverged clusters are deemed to represent complexes with largely (but not completely) non-overlapping distributions, N. hibernica only little differentiation was found, which may however reflect geographically more restricted sampling. However, geographical subdivision differ. divisions crassa follow an east–west pattern Northern Europe whereas that north–south pattern, distinct Fennoscandian clade. deep mitochondrial splits among populations (model-corrected distances 26–36%) suggest divergence lineages predate Pleistocene glaciations. This study provides insight into biogeographic distribution copepods.