Caudal pneumaticity in derived titanosaurs (Dinosauria: Sauropoda)

ZURRIAGUZ VIRGINIA; CERDA IGNACIO

CRETACEOUS RESEARCH (PRINT)

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2017

0195-6671

Among extant vertebrates, only birds have a respiratory system associated with pneumatic diverticula.However, several extinct clades also had pneumatic diverticula, including the sauropod dinosaurs.Among sauropods, Saltasaurini are characterized by extreme postcranial pneumaticity, which extends asfar down the spinal column as the posterior caudal vertebrae. In this paper the pneumatic foramina inboth the neural arches and the centra are described in detail, and the relative proportion of air spaces inthe caudal vertebrae is established, revealing that the skeleton of Rocasaurus muniozi was more pneumatizedthan that of Neuquensaurus australis, with Saltasaurus loricatus intermediate. The level ofpneumatization varies between the three saltasaurine taxa: in Neuquensaurus, only the neural arch ispneumatized, whereas in the other two saltasaurines both neural arches and centra are pneumatized.This allows us to hypothesize that the timing of pneumatization varied between the three species, withRocasaurus muniozi pneumatized earliest in ontogeny. This ontogenetic pattern is correlated withevolutionary derivation: the most derived taxa show pneumatization in both the neural arch and thecentrum.