Anchisaurus

Skeletal reconstruction of Anchisaurus (after Marsh )

• Portland lineup Massachusetts, Connecticut
• Possibly South Africa

• Anchisaurus polyzelus

Anchisaurus (synonyms: Megadactylus, Amphisaurus, Yaleosaurus ) was a slender, about 2.5 meter long dinosaur from the group of Plateosauria. He lived in the Lower Jurassic ( Pliensbachian to Toarcian ) in front of about 191-174 million years ago. Fossils consist almost entirely preserved skulls and skeletons have been found in Massachusetts and Connecticut in the northeastern United States.

The first fossils of a Anchisaurus were discovered in 1818, but they were considered human bones, because at that time they had no experience with dinosaur fossils. It was not until 1855, after the discovery of more bones, they identified it as a reptile bones. A description of the animal was in 1865 by Edward Hitchcock in 1885 by Othniel Charles Marsh.

There is only one safe way Anchisaurus polyzelus. Some bone fragments found in South Africa were described as Gyposaurus capensis and attributed to 1971, the new way Anchisaurus capensis, but are regarded as nomina dubia.

Features

Anchisaurus was a small, lightly built dinosaurs and was about 2.5 meters long and 27 kilograms. Unusually for prosauropods had his skull window for the external nasal openings less than 50 percent of the diameter of the bony orbits. In the upper jaw, he had five teeth on the premaxilla and eleven on the maxilla. The teeth were slender and elongated. The number of teeth in the lower jaw is unknown. The parietal bone consisted of two separate bones.

Whether Anchisaurus was a meat and herbivores, is not yet completely clarified. However, since a larger digestive tract is compels to digest plants, it is assumed that the prosauropods have regressed to the Vierfüßigkeit. Anchisaurus could therefore represent an intermediate stage between four-legged herbivores and bipedal predators.

System

Together with Ammosaurus forms Anchisaurus the family of Anchisauridae within the prosauropods. As Anchisauridae all taxa are referred to, the Anchisaurus are closer than Melanorosaurus.