Abrictosaurus

Type Species: Abrictosaurus consors

Classification: Dinosauria - Ornithischia - Heterodontosauridae

Time Period: Early Jurassic

Location: South Africa

Diet: Herbivore or Omnivore

Abrictosaurus was a heterodontosaur that lived in South Africa during the Hettangian and Sinemurian stages of the Early Jurassic 200-190 million years ago. It’s known from the fossil remains of two individuals. Its habitat consisted of sand dunes and seasonal floodplains in a semiarid environment with sporadic rainfall. It likely practiced niche partitioning in its herbivorous eating habits, sharing the ecosystem with other heterodontosaurs like Heterodontosaurus and Lycorhinus. Other organisms in the environment included land-dwelling crocodylomorphs, early mammals, the theropod Coelophysis, and the prosauropod Massospondylus. 

Abrictosaurus had large, canine-like tusks – called ‘caniniforms’ – in both its upper and lower jaws. It had no teeth in the front of its jaws; in its place was a hard beak likely used to crop vegetation. A handful of primitive heterodontosaur features indicate that it is the most basal member of Heterodontosauridae. For example, Abrictosaurus had widely separated cheek teeth with low crowns more similar to other ornithischians, whereas Heterodontosaurus and other heterodontosaurs had high-crowned cheek teeth that overlapped each other in the jaw to form a continuous chewing surface similar to the later Cretaceous hadrosaurs. Another example is in Abrictosaurus’ tusks, which were more primitive than those of more derived heterodontosaurs. It’s widely believed that Abrictosaurus was a gregarious creature; this is indicated by the fact that one of the two specimens recovered has much smaller tusks. This may be an example of sexual dimorphism; in many modern mammals, tusks of different sizes are used to differentiate gender with musk deer, walrus, Asian elephants, and many pigs. Thus it’s likely that the fossilized remains belong to both a male and a female Abrictosaurus.