Abrictosaurus
Abrictosaurus was a heterodontosaurid dinosaur from the Lower Jurassic of what is now southern Africa. It was a small bipedal herbivore or omnivore, about 1.2 meters (4 feet) long, and weighing less than 45 kilograms (100 pounds).
| Abrictosaurus Temporal range: Early Jurassic,
| |
|---|---|
| |
| Specimen NHMUK RU B54 | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Order: | †Ornithischia |
| Family: | †Heterodontosauridae |
| Subfamily: | †Heterodontosaurinae |
| Genus: | †Abrictosaurus Hopson, 1975 |
| Species | |
| |
Abrictosaurus is usually thought to be the most basal member of the family Heterodontosauridae.[1][2] Lycorhinus and Heterodontosaurus both had high-crowned cheek teeth, which went over each other in the jaw, making a continuous chewing surface analogous to those of Cretaceous hadrosaurids. Abrictosaurus had more widely-split cheek teeth, with lower crowns, more similar to other early ornithischians.
The family as a whole has canine-like tusks.[3] Tusks were clearly present on one of the two specimens of Abrictosaurus. The upper caniniform measured 10.5 millimeters (0.4 inches) high, while the lower reached 17 mm (0.67 in).[4][5]
Abrictosaurus had smaller, less powerful forelimbs than Heterodontosaurus and one fewer phalanx bone (finger joint) in both the fourth and fifth digits of the forelimb.[6]
References
change- ↑ Norman D.B. et al. 2004. Basal Ornithopoda. In Weishampel D.B., Dodson P., & Osmolska H. (eds). The Dinosauria. 2nd ed, Berkeley: University of California Press. 393-412
- ↑ Weishampel D.B. & Witmer L.M. 1990. Heterodontosauridae. In: Weishampel D.B., Dodson P., and Osmolska H. The Dinosauria 1st ed, Berkeley: University of California Press. 486-497
- ↑ Sereno, P.C. 1986. Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2: 234-256.
- ↑ Thulborn, R.A. 1970. The systematic position of the Triassic ornithischian dinosaur Lycorhinus angustidens. Zoological Journal of the Linnean Society 49: 235-245.
- ↑ Hopson, J.A. 1975. On the generic separation of the ornithischian dinosaurs Lycorhinus and Heterodontosaurus from the Stormberg Series (Upper Triassic) of South Africa. South African Journal of Science 71: 302-305.
- ↑ Thulborn, R.A. 1974. A new heterodontosaurid dinosaur (Reptilia: Ornithischia) from the Upper Triassic Red Beds of Lesotho. Zoological Journal of the Linnean Society of London. 55: 151-175.
