Coelophysis bauri, C. rhodesiensis, C. kayentakatae, C. holyokensis

Source: http://apsaravis.deviantart.com/art/Coelophysis-bauri-405981470

Name: Coelophysis bauri, C. rhodesiensis, C. kayentakatae, C. holyokensis 

Name Meaning: Baur’s Hollow Lizard 

First Described: 1887

Described By: Cope

Classification: Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Coelophysoidea, Coelophysidae, Coelophysinae

My Eleventh Favorite Dinosaur

Coelophysis is a well known and well understood genus, representing the archetypal early, true theropod. Its known from hundreds of skeletons, many of them complete. It is known from many formations in the New Mexico and Arizona area, and occurred in the Late Triassic, about 216 to 203 million years ago, in the Carnian and Norian stages. It was lightly built, with the features of a runner, making it a nimble carnivore. It had a long neck and long tail for balance, and it could move its jaw to manipulate small prey. However, due to its small teeth, and weak forearms (showing the beginnings of an ongoing evolutionary trend for theropods to forgo the use of their forelimbs, culminating in their minuscule size in Tyrannosaurs, that, hypothetically, would have continued until the arms weren’t even there at all) it probably only hunted small, fast moving prey, using its versatile jaws to grab the prey. It probably hunted in packs, according to remains. It has been shown in many bone beds to congregate in areas of water during drought and, ultimately, die there if the drought became too much. There also is an appearance of sexual dimorphism, with remains generally coming in two different weights. Furthermore, despite prior hypotheses that Coelophysis was a cannibal in hard times, feeding on their own young, new evidence suggests that the number of young found in Coelophysis stomachs was too great to be contained in them, and instead the animals all died atop one another in the drought. Further evidence will be needed to form better conclusions about the lifestyles of these common, fascinating predators. 

Source: http://news.discovery.com/animals/dinosaurs/dinosaurs-feathers-prehistory-20130131.htm

C. rhodesiensis and C. kayentakatae were once separated out in their own genus, Megapnosaurus. They lived about 199 to 188 million years ago, during the Hettangian to Pliensbachian stages of the period.They were discovered in large numbers in the Forest Sandstone formation of Zimbabwe, the Upper Elliot Formation in South Africa, and the Kayenta Formation in Arizona. The African species, C. rhodesiensis, is more numerous in its findings than the American species; meanwhile, the species C. kayentakatae is distinguished not only by its location, but also due to the presence of two small crests on its head, much like miniature versions of that of Dilophosaurus. It lived in a somewhat wetter climate than Coelophysis bauri, due to the increased humidity in the Jurassic Period. Finally, C. rhodesiensis and C. kayentakatae also had a fairly large brain cavity, indicating that it was a much more intelligent predator than its contemporary counterparts and predecessors. 

Sources: 

Weishampel, D. B. (2007). The Dinosauria (2nd ed.). Berkeley, Calif.: University of California Press.

Dixon, D. (2007). The Complete Book of Dinosaurs. London, England: Anness Publishing.

http://en.wikipedia.org/wiki/Coelophysis

http://en.wikipedia.org/wiki/Megapnosaurus

http://www.prehistoric-wildlife.com/species/m/megapnosaurus.html

Shout out goes to @plokool, my wonderful boyfriend!