Riojasuchus tenuiceps
Name: Riojasuchus tenuiceps [The thin-headed crocodile of Rioja Province]
When: Late Triassic Period, around 220 million years ago
Where: Quebrada de los Jachaleros, San Juan Province, Argentina
Claim to fame: Riojasuchus is one of the last surviving members of a reptile group called ornithosuchids - largish predators from the dawn of the age of dinosaurs, but not dinosaurs, themselves. The skull of Riojasuchus is 25 cm long. Also, its skeleton is better known than other members of this group, making it an importance reference. Ornithosuchids were archosaurs, members of the large group that is descended from the most recent common ancestor of crocodylians and birds. In fact, ornithosuchids like Riojasuchus are just barely closer to the ancestry of crocs than to birds. Ornithosuchids are distinguished by their triangular eye sockets, which look as if they were being squeezed on the bottom by the skull openings in front of and behind them. Although many fossil archosaurs had an overhanging front of the snout, ornithosuchids took it to extremes. Ornithosuchids didn't make it into the Jurassic, the period when dinosaurs truly took over the world
- Belen von Baczko, M. B.; Ezcurra, M. D. 2013. "Ornithosuchidae: a group of Triassic Archosaurs with a unique ankle joint". In Nesbitt, S. J.; Desojo, J. B.; Irmis, R. B. (eds.). Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and Their Kin. The Geological Society. pp. 183Ð195. ISBN 978-1-86239-361-5.
- Belen von Baczko, M. B.; Julia Brenda Desojo. 2016. Cranial Anatomy and Palaeoneurology of the Archosaur Riojasuchus tenuisceps from the Los Colorados Formation, La Rioja, Argentina. PLOS One, February 2016.
- Cullen, Thomas, Derek W. Larson, Mark P. Witten, Diane Scott, Tea Maho, Kristin Brink, and Robert Reisz. 2023. Theropod dinosaur facial reconstruction and the importance of soft tissues in paleobiology. Science, 379:6639, pp. 1348-135.