Microstructure of Vertebrae, Ribs, and Gastralia of Triassic Sauropterygians—New Insights into the Microanatomical Processes Involved in Aquatic Adaptations of Marine Reptiles

Isolated ribs and vertebrae of Middle Triassic sauropterygians are studied. The vertebrae have a well‐defined large cavity in their centra, which is a unique feature and is without any modern analogue. The articular facets of vertebrae are made of endochondral bone including calcified as well as uncalcified cartilage. Vertebrae are pachyosteosclerotic in the pachypleurosaurs Neusticosaurus and Serpianosaurus from the Alpine Triassic, and...