LOOK ON THE FOSSIL RECORD OF TURRIDS, YE PALEONTOLOGISTS, AND DESPAIR!

The neogastropod clade Conoidea includes the familiar cone snails (Conidae) and 17 additional families, all but one of which (Cryptoconidae) are extant. There are over 5,000 extant species and 380 genera of Conoidea, all of which are venomous predators. Many conoideans other than Conidae and Terebridae (auger snails) are often called “turrids” and are often characterized by the presence of an indented “turrid notch” at the terminal edge of the shell's sutural ramp. Conoideans have a rich fossil record that extends to the Cretaceous, but a combination of hyperdiversity, subtle differences between species, often small shell size, and taxonomic complexity has resulted in them being little studied, despite their evolutionary success.

We have begun to explore the fossil record of conoideans from the Plio-Pleistocene of the southeastern United States as part of a broader project to catalog and document the fossil records of all gastropod and bivalve species from this system. A newly developed database derived from literature and museum collections shows that nearly 200 species-group names have been applied to conoideans (excluding Conidae) from this system, fewer than 10 of which were described in the past 50 years. We present preliminary assessments of the Pliocene to Recent diversity patterns of individual subclades from the Southeast.

Preliminary data from the Paleobiology Database demonstrate that occurrences assigned to the conoidean family Turridae from this study region are much less likely to be assigned to species than most other co-occurring mollusk families, with about 56% of occurrences assigned to a species. Online specimen data derived from the Florida Museum of Natural History similarly show that just under 50% of records from this system assigned to Turridae are also assigned to species.

Because records unidentified to species are unevenly distributed among molluscan families, attempts to restrict analyses to only records which are well-resolved taxonomically may impact our overall understanding of biodiversity and ecology, especially when they result in the exclusion of species-rich clades. Our results highlight the importance of primary systematic research and museum collections for assessing important but understudied components of the biodiversity of fossil molluscan faunas.