Abstract

Conella, Eurypyrene, and Parametaria are three taxa of columbellid neogastropods native to the Neogene American tropics whose monophyly and relationships have traditionally been confused. The primary objective of this study is to reconstruct the phylogenetic relationships of the tropical American species in these genera, to evaluate their monophyly, and to establish their constituencies. Parsimony-based phylogenetic analysis was used to generate phylogenetic topologies, after which the shortest trees were evaluated to minimize stratigraphic debt using a stratigraphic character added to the data set. The morphologically most parsimonious topologies are well resolved but the main clades are not well supported. Stratocladistic evaluation of the most parsimonious trees resulted in four morphologically and stratigraphically shortest trees. Overall, the resultant trees suggest that Conella and Eurypyrene are monophyletic with minor changes to their traditional constituency, but the resulting trees do not support monophyly or constituency of Parametaria, except in a very restricted sense, or as a paraphyletic group including one or more other traditional genera.