Just slightly more advanced than the "fabrosaurs" (or "lesothosaurs"), these most basal genasaurs are remarkable for their possession of armor plating and several supraorbital bones, among more features, and run the gamut from most basal Scutellosaurus, an earliest Early Jurassic form, to Wuerhosaurus, from the late Early Cretaceous, with most forms being Late Jurassic in age. The advanced thyreophores are called eurypodans, and are split into two lineages, the stegosaurs and the ankylosaurs, discussed more extensively below. The decidely stegosaurian appearance of Scelidosaurus and Scutellosaurus are possibly autapomorphic of Stegosauria, and would suggest a closer affinity than to Ankylosauria or separate from either, but this has not been tested yet.

These are the most basal of the thyreophorans, including the small, most primitive Scutellosaurus, and the more advanced Scelidosaurus. These animals lack the specializations of the ankylosaurs and stegosaurs, such as paired dorsal armor, or the broad feet, giving the group the name Eurypoda ("broad feet").



The basal thyreophoran Scelidosaurus harrisoni ("Harrison's limb
lizard"), head shot demonstrating the corner cranial spikes.

Including the nodosaurs, polacanths, shamosaurs, and ankylosaurs, these animals have broad ilia, very wide bellies, short necks and broad skulls with overgrown cranial sutures bearing ossified armor plating fused to the skull and advanced lateral armor, unlike the stegosaurs.

Ankylosauridae?




The basal ankylosaurid ankylosaurian eurypodan Minmi
paravertebra ("Minmi [Station] near the vertebrae"), based
largely on Minmi sp., in dorsal and lateral aspects.

Stegosaurians can be separated into three levels: the basal huayangosaurids, with some lateral armor and broad cheeks; the more advanced but still primitive dacentrures, with short plate-like spines and mostly spinous dorsal armor, though lacking lateral armor; and the advanced stegosaurids, with advanced dorsal plates or spike-like plates, developed tail spikes, narrow skulls, and long hind legs.

Stegosauridae




The mildly-advanced or progressivly-basal stegosaurid eurypodan
Lexovisaurus durobrivensis.

Not prepared yet -- please have patience.

Go to the Last Page

My appreciation can be found here. This Page and all other Qilong Pages are the © property of Jaime A. Headden. Gain my permission to use any images or source material, but references are free for all.