Pronunciation: SEE-dar-PEL-tuh
Meaning: Cedar Shield
Author/s: Carpenter et al. (2001)
Synonyms: None known
First Discovery: Utah, USA
Discovery Chart Position: #479
Cedarpelta bilbeyhallorum
Gastonia aside, Cedarpelta bilbeyhallorum is the oldest ankylosaurid from North America and the most primitive known member of Ankylosauridae—the club-tailed ankylosaurs. Yet according to name-coining-author Ken Carpenter's 2001 diagnosis, it's most closely related to the Asian Gobisaurus domoculus and Shamosaurus scutatus. It's also one of the largest ankylosaurids, rivalling Ankylosaurus magniventris itself, size-wise, but it hasn't been without its doubters.
A particularly long snout, weakly ornamented skull, and no evidence of a "typical" ankylosaurid ankylosaur clubbed tail led Vickaryous et al. (2004) to suspect an affinity with the spike-shouldered nodosaurids: the ankylosaurs with, well, particularly long snouts and weakly ornamented skulls, that lack clubbed tails. As it happens, no pre-Campanian-aged North American ankylosaurids appear to have had a tail club, and the remains of Cedarpelta lack a tail end that could've held a club anyway. It does, however, sport a closed "window" on the side of the skull behind the eye socket (the lateral temporal fenestra), which is only known in ankylosaurids, so Carpenter's original identification was right on the money.
The paratype skull of Cedarpelta was discovered disarticulated while the holotype was missing its lower jaw and most of a snout. But far from being a bad thing, it afforded palaeontologists the first glimpse inside of an ankylosaurid noggin and the opportunity to study its individual bones, which, until this point, had always been part of an impenetrable, heavily fused unit.
A particularly long snout, weakly ornamented skull, and no evidence of a "typical" ankylosaurid ankylosaur clubbed tail led Vickaryous et al. (2004) to suspect an affinity with the spike-shouldered nodosaurids: the ankylosaurs with, well, particularly long snouts and weakly ornamented skulls, that lack clubbed tails. As it happens, no pre-Campanian-aged North American ankylosaurids appear to have had a tail club, and the remains of Cedarpelta lack a tail end that could've held a club anyway. It does, however, sport a closed "window" on the side of the skull behind the eye socket (the lateral temporal fenestra), which is only known in ankylosaurids, so Carpenter's original identification was right on the money.
The paratype skull of Cedarpelta was discovered disarticulated while the holotype was missing its lower jaw and most of a snout. But far from being a bad thing, it afforded palaeontologists the first glimpse inside of an ankylosaurid noggin and the opportunity to study its individual bones, which, until this point, had always been part of an impenetrable, heavily fused unit.
(Bilbey and Hall's Cedar Mountain shield)
Etymology
Cedarpelta is derived from "Cedar" (for the Cedar Park Formation) and the Greek "pelte" (shield) in reference to its place of discovery and its armour.
The species epithet,
bilbeyhallorum (bil-bee-haw-LOR-um), honours Sue Ann Bilbey and Evan Hall who discovered the type locality.
Discovery
The first fossils of Cedarpelta were discovered at the Price River I site in the base of the Mussentuchit Member (previously thought to be the top of the older Ruby Ranch Member) of the Cedar Mountain Formation, Carbon County, Utah, USA, by Sue Ann Bilbey and Evan Hall.
The holotype (CEUM 12360) is a partial skull, lacking the lower jaw. Paratypes, from the same quarry, include a disarticulated skull, a partial neck vertebra and 2 neck ribs, 5 partial back vertebrae, 4 hip vertebrae, 15 tail vertebrae, part of a right upper arm, a left lower arm bone, 3 parts of pelvic girdle, 9 hand bones, and 13 pieces of assorted armour. Referred material includes a neck vertebrae, a shoulder bone, two tail vertebrae, two upper arm bones, a hip bone, a thigh and a shin, from Price River 2 site in the Mussentuchit Member of the Cedar Mountain Formation at Emery County, Utah, near the quarry that produced the holotype of Peloroplites cedrimontanus.
