Together, this evidence of gregarious behaviors suggests that ceratopsians
developed complex social behaviors long before they possessed extreme cranial ornamentations, says Barrett.
One piece of evidence claimed by the proponents of galloping ceratopsians is that their "massive shafted" limb bones are prima facie evidence of cursoriality (Bakker, 1980).
Humeral length and minimum diameter values were recorded for 10 type specimens representing 10 genera of ceratopsians, from both the families Ceratopsidae and Protoceratopsidae (Table 1).
The use of skull length as a size indicator is complicated in ceratopsians by the presence of a large frill extending the posterior margin of the skull.
If the question of ceratopsian galloping could be resolved by the dimensions of humeral diameter, the results would indicate that ceratopsians did not gallop; the dimensions of the humeral shaft diameter provide absolutely no evidence of adaptation to increased stresses imposed by galloping.
Among the last dinosaurs to survive were Montana's and Alberta's hadrosaurs and ceratopsians, the latter so common that paleontologist Robert Bakker of the University of Colorado calls them "Cretaceous cockroaches.
They've found more than 300 dinosaurs from 35 species, duck-billed hadrosaurs to horned ceratopsians.
The single track described in this report compares favorably with published accounts of tracks and skeletal features for those previously published records for the more derived ceratopsians.
With the advent of new discoveries of ceratopsians, multiple biogeographic models now exist to explain the global distribution of their skeletal remains (Chinnery et al.
2000): The fossil record, systematics and evolution of pachycephalosaurs and ceratopsians from Asia.
Liaoceratops] shows that the evolution of ceratopsians
is more complicated than we'd thought," says Catherine A.
Johnson says that Torosaurs, Triceratops and probably all ceratopsian
dinosaurs had sprawling lizard-like forelimbs after all, and therefore could not gallop.
Hadrosaurs or duck-billed dinosaurs, along with the small ornithopod Thescelosaurus, preferred to live along the edge of rivers, while Ceratopsians
preferred to be several miles inland.
And among some 10,000 bones I finally discovered four other specimens that could be related to ceratopsians
The sizes and shapes of crystals from the fossil teeth suggest that the ceratopsian
dinosaurs, relatives of Triceratops, may have eaten a high proportion of tough-leafed cycads, whereas the hadrosaurs, or duck-billed dinosaurs, probably favored ferns.