Temporal range: Early Cretaceous, Barremian
Gilpin et al., 2007
Gilpin et al., 2007
Cedrorestes is a genus of iguanodontian dinosaur from the Early Cretaceous of Utah. It is based on an incomplete skeleton which was found in the Barremian-age Yellow Cat Member of the Cedar Mountain Formation.
Discovery and history
Cedrorestes is based on DMNH 47994, a partial skeleton including rib fragments, a sacrum, the left ilium and a portion of the right, a right thighbone, the right third metatarsal, and fragments of ossified tendons. These remains were recovered from near the top of the Yellow Cat Member of the Cedar Mountain Formation, in east-central Utah. They were found scattered in a calcareous mudstone, and showed evidence of pre-burial damage, from weathering or trampling.
This genus can be told apart from other iguanodontian ornithopods by its combination of a tall ilium, as is present in Iguanodon-like ornithopods, with a large lateral bony process above and behind the acetabulum and joint surface for the ischium, as is seen in hadrosaurids. David Gilpin and his coauthors, who described the specimen, noted that the lateral process has been considered diagnostic for hadrosaurids, and interpreted the combination of anatomical characteristics in Cedrorestes as evidence that the genus was close to the division between hadrosaurids and iguanodontids. They placed their new genus in Hadrosauridae, as the earliest known hadrosaurid.
The etymology of the generic name is, from Latin, cedrus (cedr-); "cedar" + Greek oros-; "mountain", after the Cedar Mountain formation, where the fossil was found + Greek suffix ending -etes; "dweller". The specific epithet crichtoni is after Michael Crichton, author of Jurassic Park and The Lost World.
Paleoecology and paleobiology
The Yellow Cat Member of the Cedar Mountain Formation is known for its dinosaurs, including the small coelurosaurian theropod Nedcolbertia, the dromaeosaurid Utahraptor, brachiosaurid sauropod Cedarosaurus, and heavily armored ankylosaurid Gastonia.
Whether a basal hadrosaurid or derived non-hadrosaurid iguanodontian, Cedrorestes would have been a large herbivore capable of moving both bipedally or on all fours. The structure of its hip indicates that it had hadrosaurid-like leg muscles, but the functional significance of the changes in leg muscles from the iguanodontian layout to the hadrosaurid layout, and resulting differences in movement (if any), are not yet understood. Detailed interpretations of the paleobiology of Cedrorestes must wait for the discovery of more extensive remains.
- Gilpin, David; DiCroce, Tony; Carpenter, Kenneth (2007). "A possible new basal hadrosaur from the Lower Cretaceous Cedar Mountain Formation of Eastern Utah". In Carpenter, K. Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Bloomington and Indianapolis: Indiana University Press. pp. 79–89. ISBN 0-253-34817-X.
- Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Osmólska, Halszka; Dodson, Peter. The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561. ISBN 0-520-06727-4.
- Weishampel, David B.; Barrett, Paul M.; Coria, Rodolfo A.; Le Loeuff, Jean; Xu Xing; Zhao Xijin; Sahni, Ashok; Gomani, Elizabeth, M.P.; Noto, Christopher R. (2004). "Dinosaur Distribution". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka. The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 517–606. ISBN 0-520-24209-2.
- Horner, John R.; Weishampel, David B.; and Forster, Catherine A. (2004). "Hadrosauridae". The Dinosauria, 2nd edition. 438–463.
- Norman, David B. (2004). "Basal Iguanodontia". In Weishampel, D.B.; Dodson, P.; Osmólska, H. The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 413–437. ISBN 0-520-24209-2.