Podokesaurus

Podokesaurus; Temporal range: Early Jurassic,
	Holotype specimen, with tail and uncertain bones at left, and body at right
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	Theropoda
Superfamily:	†Coelophysoidea
Genus:	†Podokesaurus; Talbot, 1911
Species:	†P. holyokensis
Binomial name
	†Podokesaurus holyokensis; Talbot, 1911
Synonyms
	Coelophysis holyokensis (Talbot, 1911) Colbert, 1964;

Podokesaurus is a genus of coelophysoid dinosaur that lived in what is now the eastern United States during the Early Jurassic Period. The first fossil was discovered by the geologist Mignon Talbot near Mount Holyoke, Massachusetts, in 1910. The specimen was fragmentary, preserving much of the body, limbs, and tail. In 1911, Talbot described and named the new genus and species Podokesaurus holyokensis based on it. The full name can be translated as "swift-footed lizard of Holyoke". This discovery made Talbot the first woman to find and describe a non-bird dinosaur. The holotype fossil was recognized as significant and was studied by other researchers, but was lost when the building it was kept in burned down in 1917; no unequivocal Podokesaurus specimens have since been discovered. It was made state dinosaur of Massachusetts in 2022.

Estimated to have been about 1 m (3 ft) in length and 1–40 kg (2–90 lb) in weight, Podokesaurus was lightly constructed with hollow bones, and would have been similar to Coelophysis, being slender, long-necked, and with sharp, recurved teeth. The vertebrae were very light and hollow, and some were slightly concave at each end. The cervical (neck) vertebrae were relatively large in length and diameter compared to the dorsal (back) vertebrae, and the caudal (tail) vertebrae were long and slender. The humerus (upper-arm bone) was small and delicate, less than half the length of the femur (thigh-bone). The pubis (pubic bone) was very long, expanding both at the front and hind ends. The femur was slender, nearly straight, had thin walls, and was expanded at the back side of its lower end. The three metatarsals of the lower leg were closely appressed together forming a compact structure.

Since it was one of the few small theropods known at the time it was described, the affinities of Podokesaurus were long unclear. It was placed in the family Podokesauridae along with other small theropods, and was speculated to have been similar to a proto-bird. It was suggested it was a synonym of Coelophysis and a natural cast specimen was assigned to it, but these ideas are not currently accepted. The family Podokesauridae is not in use anymore, having been replaced by Coelophysidae, and Podokesaurus is thought to have been a coelophysoid. As such, Podokesaurus would have been a fleet-footed predator, with powerful forelimbs and grasping hands. It is estimated it could have run at 15–20 km/h (9–12 mph). Podokesaurus is thought to have been collected from the Portland Formation, the age of which has long been unclear, but is currently believed to date to the Hettangian–Sinemurian stages of the Early Jurassic, between 201 and 190 million years ago.