Sauropodomorphs
- largest land animals of all time
- two groups:
a) Prosauropods
b) Sauropods
Main distinguishing features:
1) heads very small compared to body size
2) at least 10 elongated vertebrae in relatively long necks
3) spatulate teeth
4) short feet
5) very large claws on first digits of forefeet
6) late Triassic to end of Cretaceous
Prosauropods
- similar to Sauropods, but much smaller and more slender.
- main evolutionary novelty is small 5th digit on hind foot ( as compared to large 5th digit on hind foot found in all Sauropods).
Evidence for Prosauropod lifestyle:
1) tracks indicate quadrupedal habit (facultative biped)
2) forelimbs 2/3 length of hindlimb
3) definitely herbivorous:
a) long neck (like giraffe)
b) cheeks present (to retain food while chewing). Evidence - recessed ridge diagonally inclined across, or on outside of, jaw
4) jaw hinge below the line of upper tooth row
5) offset of jaw allows tooth rows to be almost parallel
6) spatulate teeth (like iguana)
7) gizzard stones