An integrative taxonomic and phylogenetic approach reveals a complex of cryptic species in the 'peppermint' shrimp Lysmata wurdemanni sensu stricto

摘要

Genetic diversification is not always correlated with phenotypic dissimilarity, resulting in cryptic species complexes that pose a major challenge for biodiversity cataloguing. Resolving these complexes is of utmost importance. Herein, we tested whether Lysmata wurdemanni, a shrimp distributed over three contiguous biogeographical provinces (Virginian, Carolinian and Caribbean) and traversing various phylogeographical breaks, is a cryptic species complex. Initially, principal components analyses using 12 anatomical traits confirmed that selected populations from the three biogeographical provinces were morphologically homogeneous. Nonetheless, molecular phylogenetic analyses (16S RNA mitochondrial DNA marker) demonstrated three well-supported monophyletic clades and deep genetic distances among them. Species delimitation approaches suggested at least five (maximum of nine) putative cryptic species. Population genetics focusing on a single widespread clade distributed in the Gulf of Mexico and northwestern Atlantic coast also found deep genetic structure, and an isolation-with-migration population divergence model indicated that population divergence with incomplete lineage sorting can be invoked as the single mechanism explaining genetic dissimilarity among populations within this clade. Altogether, the information above demonstrates that L. wurdemanni is a cryptic species complex. We argue in favour of additional integrative studies to reveal the extent and magnitude of cryptic species complexes in the marine realm.