Cladistic analysis of the transisthmian genus Eurytellina (Bivalvia: Tellinoidea) based on morphological and morphometric data

One of the main questions of phylogenetic systematics has recently focused on the reliability and robustness of taxonomic data. Many recent studies are devoted almost exclusively to the molecular-morphological couplet. However, in many metazoan taxa, the presence of skeletal parts or poorly preserved soft parts is dominant in collections, making it difficult to extract genetic material. This is the case with many invertebrates and unfortunately a very common situation in mollusk collections. Herein we carry out a phylogenetic analysis of the transisthmian American tellinid bivalve genus Eurytellina based on anatomical and morphometric characters, using different ways to analyze the morphometric data under parsimony-based methods. Species in this genus are recognized as deep infaunal burrowers and present a strong filter-feeding apparatus. We included 144 taxonomically important morphoanatomical and morphometric characters and 19 landmark characters. The main results are a) Tellinota (formerly a synonym of Eurytellina) is confirmed as a taxon restricted to Africa; b) Eurytellina lineata is confirmed as sister group to all the other members of the genus; c) there is strong evidence for three robust clades, here named as groups trinitatis, nitens and punicea; d) some transisthmian sister species hypotheses are confirmed-although the pattern of speciation and radiation may be related to a complex long-term elevation of the Panama Isthmus and previous events (probably since the early Cenozoic). Furthermore, several new anatomical characters are described within the Order Tellinoidea, which should be considered in future studies.