#saurischian

Brontosaurus is the extinct genus of herbivorous sauropod dinosaur that lived in present-day United States during the Late Jurassic period. The third species of Brontosaurus is Brontosaurus yahnahpin (yahnahpin-wearing deceptive lizard), and it was described by American paleontologists James Filla and Pat Redman in 1994.

Continuing my class doodles is Euhelopus, a lesser known sauropod from Early Cretaceous China. It is known for a relatively complete skull and front half of its body.

Compsognathus! Just a little guy!

Guanlong

By José Carlos Cortés

Etymology: For Alick Walker

First Described By: Chatterjee, 1987

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia

Status: Extinct

Time and Place: Alwalkeria lived about 228 million years ago, in the Carnian age of the Late Triassic 

Alwalkeria is known from the Lower member of the Maleri Formation of Andhra Pradesh, India 

Physical Description: Alwalkeria is one of the earliest known dinosaurs, so it - like other early dinosaurs - showcases the basic dinosaur body plan: small bipedal runner. It had teeth and a skull very similar to its close cousin, Eoraptor, which had slightly different shapes depending on the position within the jaw and a somewhat small, elongate head. It had straight, slender front teeth, and backwards curved teeth in the back of the jaw, with no serrations. Little more is known about its external appearance, given the lack of remains; however, it probably would have had a long tail, short neck, and long legs and arms. Alwalkeria would probably have been only about a meter long, making it one of the smaller dinosaurs known.

Given its small size and early position on the dinosaur tree, Alwalkeria would most likely have been covered in very primitive protofeathers, but without further fossil evidence this cannot be said for certain.

Diet: Alwalkeria has teeth adapted both for feeding on meat and for feeding on plants, so it was probably an omnivore with a highly variable diet.

Behavior: Alwalkeria would have been a fairly skittish sort of animal, as early dinosaurs such as it were not very big nor very common in their ecosystems. As such, it would have used speed to get away from predators, of which there were many. It would have been curious, as well, due to being an omnivore, and a generalist one at that - so more of an opportunist than anything, looking for sources of food wherever it could. 

By Ashley Patch

Since it was a dinosaur, like other dinosaurs it would have been a fairly active animal, with a warm-blooded metabolism. It also probably took care of its young.

Ecosystem: Alwalkeria lived near a large lake environment, with mainly ferns present in the region, but also some conifers and horsetails. In the Lower Maleri environment, Alwalkeria lived alongside many other kinds of animals, though no other dinosaurs have been definitively named - only one possible prosauropod. Instead, there were the Cynodonts Exaeretodon, the Phytosaur Parasuchus, the Rhynchosaur Hyperodapedon, the Protorosaur Malerisaurus, the large temnospondyl amphibian Koskinodon, the lungfish Ceratodus, and the freshwater shark Xenacanthus. There may have also been an aetosaur of some sort. Alwalkeria probably mainly fed on small animals such as insects and reptiles not yet found in the fossil record, and it probably mainly had to look out for Koskinodon and Parasuchus in terms of predators.

Other: The original fossils described as Alwalkeria are actually a chimera, with many parts assigned to the genus actually belonging to some sort of early crocodile relative. However, there is an early dinosaur in there too, and that dinosaur seems to primarily resemble Eoraptor, though it hasn’t been thoroughly studied in a phylogenetic analysis. So, that’s what we call Alwalkeria now, even though originally there was more considered to be preserved.

~ By Meig Dickson

Sources under the cut