Cedrorestes
Early Cretaceous iguanodontian from Utah with hadrosaurid-like hip features.
Cedrorestes is a genus of iguanodontian dinosaur from the Early Cretaceous of Utah. It is known from an incomplete skeleton found in the Valanginian-age Yellow Cat Member of the Cedar Mountain Formation. The genus is notable for its combination of features that may place it near the evolutionary split between hadrosaurids and iguanodontids.
Quick Facts
- Species
- crichtoni
Facts from the source article.
Discovery and history
The dinosaur Cedrorestes is known from a single partial skeleton, cataloged as DMNH 47994. This fossil includes rib fragments, a sacrum, both ilia (the left one complete and the right one partial), a right thighbone, the right third metatarsal, and some ossified tendon pieces. Scientists found these bones in 2001 near the top of the Yellow Cat Member of the Cedar Mountain Formation in east-central Utah. The remains lay scattered in a calcareous mudstone and showed signs of damage from weather or trampling before they were buried. What sets Cedrorestes apart from other iguanodontian ornithopods is a unique mix of features: it has a tall ilium like Iguanodon-type dinosaurs, but also a large bony projection above and behind the hip socket and ischium joint, a trait typically seen only in hadrosaurids. The researchers who described it, led by David Gilpin, noted that this projection is a key hadrosaurid characteristic. They argued this combination places Cedrorestes near the evolutionary split between hadrosaurids and iguanodontids, and they classified it as the earliest known hadrosaurid. The name comes from Latin “cedrus” (cedar) and Greek “oros” (mountain), referring to the Cedar Mountain Formation, plus the Greek suffix “-etes” (dweller). The species name crichtoni honors Michael Crichton, author of Jurassic Park and The Lost World.
Paleoecology and paleobiology
The Upper Yellow Cat Member, where Cedrorestes was found, also contains fossils of other dinosaurs such as the ornithopod Hippodraco, an unnamed sail-backed iguanodontid, the armored dinosaur Gastonia, the brachiosaurid Cedarosaurus, the turiasaurian Moabosaurus, the primitive ornithomimosaur Nedcolbertia, the theropod Martharaptor (possibly a therizinosaur or oviraptorosaur), and the large dromaeosaurid Utahraptor. 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 hadrosaurid-like leg muscles, but the functional significance of these changes and any resulting differences in movement are not yet understood. Detailed interpretations of its paleobiology must await more extensive remains.
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