Early Jurassic Trochotomidae (Vetigastropoda, Pleurotomarioidea) from the Neuquén Basin, Argentina

FERRARI, S. MARIEL; DAMBORENEA, SUSANA E.; MANCEÑIDO, MIGUEL O.; GRIFFIN, MIGUEL

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Lawrence; Año: 2015 vol. 81 p. 331 - 345

0022-3360

Trochotomidae is a small but distinctive extinct family of pleurotomarioidean gastropods characterized bytrochiform shells with an elliptical trema. Two new species of trochotomids are described from Pliensbachian depositsin the Neuquén Basin, Argentina. The new genus-group name Placotoma is proposed to replace thepre-occupied name Discotoma Haber non Mulsant. The record of Trochotoma (Trochotoma) protonotialis newspecies and Trochotoma (Placotoma) neuquensis new species in the early Jurassic of Argentina extends the paleobiogeographicaldistribution of the genus (and the family) to the Southern Hemisphere. The new taxa reported hererepresent a component of the pleurotomarioidean adaptive radiation that took place in the Tethyan region during theearliest Jurassic. They are related to local patch coral reefs of shallow, open-marine paleoenvironments, agreeing withthe known habitat of most species of this family. The group was well represented in the Tethyan region during theMesozoic, especially during the Jurassic, and the new species represent its southernmost occurrence.