Stegopelta

Taxobox
name = "Stegopelta"
fossil_range = Late Cretaceous
regnum = Animalia
phylum = Chordata
classis = Sauropsida
superordo = Dinosauria
ordo = Ornithischia
subordo = Thyreophora
infraordo = Ankylosauria
familia = uncertain
genus = "Stegopelta"
genus_authority = Williston, 1905
subdivision_ranks=Species
subdivision=
*"S. landerensis" Williston, 1905 (type)

"Stegopelta" (meaning "roofed shield") is a genus of armored dinosaur. It is based on a partial skeleton from the latest Albian-earliest Cenomanian-age Lower and Upper Cretaceous Belle Fourche Member of the Frontier Formation of Fremont County, Wyoming.

History

In 1905, Samuel Wendell Williston described FMNH UR88, a partial armored dinosaur skeleton consisting of a maxilla fragment, seven cervical and two dorsal vertebrae, part of a sacrum and both ilia, caudal vertebrae, parts of the scapulae, both humeral heads, portions of an ulna and both radii, a metacarpal, partial tibia, metatarsal, and armor including a shoulder spine and neck ring.Williston, S.W. (1905). A new armored dinosaur from the Upper Cretaceous of Wyoming. "Science" 22:503-504.] Carpenter, K., and Kirkland, J.I. (1998). Review of Lower and middle Cretaceous ankylosaurs from North America. In: Lucas, S.G., Kirkland, J.I., and Estep, J.W. (eds.). "Lower and Middle Cretaceous Terrestrial Ecosystems". "New Mexico Museum of Natural History and Science Bulletin" 14:249-270.] Unfortunately, it was in poor condition, as it had eroded from a slope and been walked on by cattle.Moodie, R.L. (1910). An armored dinosaur from the Cretaceous of Wyoming. "Kansas University Science Bulletin" 5:257-273.] Ankylosaurians being very poorly known, Williston compared his new genus to "Stegosaurus", and the armor to that of "Glyptodon"; like that mammal, "Stegopelta" had a fused section of armor (in its case over the pelvis). Moodie redescribed it in 1910, and considered it to be close to, if not the same as, "Ankylosaurus".

The genus fell into obscurity. Walter Coombs synonymized it with the more famous but equally poorly-known "Nodosaurus" in his 1978 redescription of the Ankylosauria.Coombs, Jr., W.P. (1978). The families of the ornithischian dinosaur order Ankylosauria. "Palaeontology" 21(1):143-170. ] It was reinstated as a valid genus by Ken Carpenter and James Kirkland (1998), who recognized it as having distinct vertebral and armor characteristics. Tracy Ford took this farther in 2000, assigning it to a new subfamily in Ankylosauridae based on armor characteristics, which he called Stegopeltinae and also included "Glyptodontopelta".Ford, T.L. (2000). A review of ankylosaur osteoderms from New Mexico and a preliminary review of ankylosaur armor. In: Lucas, S.G., and Heckert, A.B. (eds.). "Dinosaurs of New Mexico". "New Mexico Museum of Natural History and Science Bulletin" 17:157-176.] This has not been generally accepted, but most recent reviews have accepted "Stegopelta" as a distinct genus with uncertain affinities.Carpenter, K. (2001). Phylogenetic analysis of the Ankylosauria. In: Carpenter, K. (ed.). "The Armored Dinosaurs". Indiana University Press:Bloomington, 455-483. ISBN 0-253-33964-2] Vickaryous, M.K., Maryańska, T., and Weishampel, D.B. (2004). Ankylosauria. In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.). "The Dinosauria" (second edition). University of California Press:Berkeley, 363-392. ISBN 0-520-24209-2]

Paleobiology

Because it is so poorly known, at this point all that can be said about the habits and life of "Stegopelta" is that it was a slow quadrupedal herbivore that fed low to the ground and relied on its armor for defense.

Its armor included a fused region over the sacrum, and shoulder spines that may have been split, as seen in "Edmontonia".

References