
A note about the anatomy of this basal stegosaur. Huayangosaurus was placed within its own family on account of its rather basal skeleton, which we previously glossed over vaguely. The spikes on the shoulders I think we have covered more than enough of this past week. The skull, though, to the right, we have barely mentioned other than to state that it is very basal and almost resembles that of a nodosaur. After I made that comment I checked the group's tree and realized, though I still have not found an "official" opinion which backs up my assertion, that the head probably looks this way in part because it is so basal that it represents the first species on the stegosaur branch of the tree after stegosaurs and ankylosaurs began to evolve away from each other. Should that prove correct, and anyone that can back me up or disprove it is more than welcome to chime in, then I would feel pretty darned awesome about it. However, there is more than a neat theory behind the skull. The skull itself has premaxillary teeth, a trait not found in stegosaurs. Early nodosaurs also have some small evidence of premaxillary teeth prior to the beak adaptations of ankylosaurus and later nodosaurs showing in the fossil record.
No comments:
Post a Comment