Silesaurus

Extinct genus of reptiles

Silesaurus is a genus of silesaurid dinosauriform from the Late Triassic, of what is now Poland.

Herbivory has been suggested for silesaurids in general and Silesaurus in particular based on tooth shape, and a 2014 study by the paleontologists Tai Kubo and Mugino O. Kubo of microwear on its teeth found it consistent with herbivory on soft objects, by comparing with wear on the teeth of extant mammals, though omnivory could not be ruled out. A 2019 study by paleontologist Martin Qvarnström and colleagues examining coprolites (fossil dung) that contained beetles attributed them to Silesaurus based on size and other factors. These researchers suggested that while Silesaurus could exploit plant resources, it was not strictly a plant eater. They pointed out that the teeth of Silesaurus were not numerous or regularly spaced, and lacked the coarse serrations typical in herbivores. They hypothesized that the beak like jaws were adapted for pecking small insects off the ground like modern birds. They cautioned that there could have been other food sources that were not preserved in the coprolites, such as soft prey, plant fragments, and larger, more resistant items that were regurgitated, and that beetles could have been a seasonal food item. If so, this would represent the earliest known occurrence of this highly derived mode of feeding and have implications for the understanding of the evolutionary adaptations that would eventually lead up to the origin of dinosaurs.

Silesaurus and silesaurids in general have been considered quadrupedal due to their long, gracile forelimbs. In 2010, the paleontologists Rafał Piechowski and Jerzy Dzik considered such proportions typical of fast running, quadrupedal animals, but noted that the long tail of Silesaurus which would have acted as a counterweight to the body, as well as the very gracile forelimbs, indicates it retained the ability for fast bipedal running. Piechowski and the paleontologist Mateusz Tałanda concluded in 2020 that the short hindlimbs combined with the elongated forelimbs supported the idea that it was an obligate quadruped.

Silesaurus lived in a subtropical environment similar to the modern Mediterranean basin with alternating summer monsoons and dry winters. The animal shared its environment of extensive swamplands and fern vegetation with a wealth of invertebrates as well as dipnoan and ganoid fishes, temnospondyls, phytosaurs and early pterosaurs.