Plateosaurus

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Plateosauridae

Overview: “Prosauropod” is a casual term used to refer to sauropodomorphs, mainly bipedal ones, that fall outside of the Sauropoda proper. It used to be considered a scientific clade, but it has since fallen out of use, with “prosauropods” representing many separate lineages. One of the most well known of the “prosauropods” was Plateosaurus – the “broad lizard”. The genus was established in 1837 by the German paleontologist Hermann von Meyer, though what trait on the creature he was referencing as “broad” has since become a mystery. Researchers later recognized Plateosaurus as a dinosaur, with it becoming the namesake of the family Plateosauridae. Various other genera of “prosauropod” were referred to this family, though today only a handful are accepted as true plateosaurids. Since then, multiple dozens of Plateosaurus specimens have been found, including those of different growth stages. In addition to Germany, fossils have been reported from France, Switzerland and off the coast of Norway (unearthed by oil drilling). Fossils found in Greenland have since been given their own genus, known as Issi, which is still seen as a fellow plateosaurid.

The basic body plan of Plateosaurus was quite stereotypical for a “prosauropod”. While some early restorations depicted it as quadrupedal, studies of its wrist anatomy in recent decades have proven it was restricted to bipedal movement. It couldn’t support its weight with its hands. This freed up its hands, and namely its claws, for other uses, including foraging or for defense. Its neck was long, topped by a fairly small, slender skull. The jaws had a notable downward curve towards the end and the teeth were relatively simple. Plateosaurus mainly fed upon plants like ferns, cycads or conifers. Notably, this animal doesn’t appear to have had one standard size as an adult. Adult specimens of the genus could be anywhere between five to even ten meters long. While not as heavily built as its later sauropod relatives, Plateosaurus was decently large by Late Triassic standards. Plateosaurus fossils are known from formations like the Trossingen and Löwenstein. It probably lived alongside other dinosaurs like Procompsognathus and Liliensternus, the latter of which may’ve been a major threat to Plateosaurus itself. It lived in a highly seasonal environment with dry and wet periods.