Paleontology. T. rex clan evolved head first.
Erik
E
Stokstad
D000818:Animals; D005075:Biological Evolution; D001824:Body Constitution; D002681:China; D025061:Dinosaurs / Q000033:anatomy & histology*; D005121:Extremities / Q000033:anatomy & histology; D005241:Feathers / Q000033:anatomy & histology; D005580:Fossils; D012886:Skull / Q000033:anatomy & histology