Segisaurus lived about 183 million years ago during the Jurassic period. Segisaurus was roughly the size of a goose and was a primitive bipedal theropod. Segisaurus was roughly 1 metre (3 feet) long, half a metre (1.5 feet) tall and weighed about 4-7 kilograms. It was nimble and insectivorous, although it may have scavenged meat also. It was bird-like in structure, with a flexible, elongated neck and stout body. Segisaurus was three-toed and had powerful legs that were long compared to its body length. Like its legs, Segisaurus had a long tail and long forearms. Its collar bone was not unlike a bird's, thus strengthening scientists' arguments that dinosaurs were related to avians. Segisaurus is described from the only specimen ever found. The holotype, however, was a sub-adult, so that the full size of Segisaurus as an adult may never be known. Strangely, clavicles were found on the Segisaurus specimen, which were unknown in other dinosaurs from that era.
History of discovery Edit
The first discovery of Segisaurus was by Max Littlesalt, a Navajo Indian who kept livestock inside Tsegi Canyon. After discovering the remains in the Navajo Sandstone formation of Arizona, Littlesalt pointed out the fossils to archeologists on an expedition inside the canyon. Other than the first finding of Segisaurus, no other specimens have been discovered. After its initial description by Charles Lewis Camp, the holotype went relatively ignored for the next half century. When the specimen was investigated during this period, all who viewed it commented on the presence of clavicles and the solid bone structures the dinosaur had. According to recent reports, Segisaurus is vital in understanding the evolution of early theropods.
Restoration of the holotype skeleton from 1936 When the specimen of Segisaurus was discovered, Camp likened it to that of a "sitting hen", due to the position the dinosaur's remains were in. Other theropods used this positions to sleep or stay sheltered during sand and ash storms, and indeed the Segisaurus holotype was found in a bed of sand stone, suggesting that the dinosaur had been submerged in a layer of sand and died. This is still only a hypothesis, as no nest or den materials were discovered along the Segisaurus specimen. Another speculative interpretation from Camp has attracted less attention: that the "splint-like" neck ribs supported a Draco-like patagium along the neck, to improve the animal's ability to move quickly. In September 2005, the Journal of Vertebrate Paleontology published a report which re-examined the remains of the Segisaurus holotype. The authors concluded, that although very unusual, Segisaurus was firmly a coelophysoid. They also noted that Segisaurus was probably a relative of Procompsognathus.