Brittle stars from the Lower Cretaceous of Patagonia: first ophiuroid articulated remains for the Mesozoic of South America

FERNÁNDEZ D. E.; GIACHETTI, L.; STOHR, S.; THUY, B.; PEREZ, D.; COMERIO M.; PAZOS P.J.

ANDEAN GEOLOGY

SERVICIO NACIONAL GEOLOGIA MINERVA

Lugar: Santiago de Chile; Año: 2019

0718-7092

The first articulated remains of ophiuroids for the Mesozoic of South America are described from theLower Cretaceous of Neuquén Basin, Argentina. The taxonomic analysis allows the assignment of the material described herein to the extinct genus Ophiopetra. The specimens belong to a new species, but considering the poor preservation, anew name is not introduced, as it would be based on an incomplete diagnosis. Certain characteristics (e.g., the diameterof the disc, the width/height ratio of the vertebrae) suggest that these ophiuroids are paedomorphic specimens. In lightof the latest classification of the Ophiuroidea, and new insights on the spine articulation microstructure of Ophiopetralithographica presented herein, a transfer of Ophiopetra to the family Ophionereididae within the order Amphilepididais proposed. This material expands the palaeogeographic record of this genus, since it represents the first remains ofOphiopetra described in the Southern Hemisphere. It is also the first Cretaceous record of the genus worldwide.