PHYLOGENETIC ANALYSIS OF THE FLORIDA PLIO-PLEISTOCENE TURRITELLA USING CONTINUOUS CHARACTERS

The Turritella species of the Florida Plio-Pleistocene are abundant, diverse, and morphologically variable. Little is known about the evolutionary history of this group, however, making in-depth studies of the effects of the Plio-Pleistocene regional mass extinction on different lineages and clades within the group extremely difficult. Much of the difficulty in developing a phylogenetic tree for Turritella is due to the paucity of discrete homologous characters. A new implementation of the phylogenetic analysis software Tree analysis using New Technology (TNT) allows the use of continuous characters based on geometric morphometric analysis of shell shape in addition to the traditional characters previously available (e.g., whorl number/shell height, growth line shape, protoconch type and ontogenetic spiral cord development). The phylogeny that results from this method will allow the study of distribution of body size, growth rate, and longevity in different clades. A preliminary phylogenetic analysis suggests that extinction is distributed between clades, and that large body size is polyphyletic.