| Planicoxa | |
|---|---|
 | |
| Life restoration ofPlanicoxa | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | †Ornithischia |
| Clade: | †Ornithopoda |
| Clade: | †Ankylopollexia |
| Clade: | †Styracosterna |
| Genus: | †Planicoxa DiCroce &Carpenter,2001 |
| Species: | †P. venenica |
| Binomial name | |
| †Planicoxa venenica DiCroce & Carpenter, 2001 | |
Planicoxa is agenus of advancediguanodontiandinosaur from the EarlyCretaceous of North America. It is known from the partial skeletons of several individual specimens. Its fossils were discovered inUtah,United States.
The type species for the genus isPlanicoxa venenica, first described by Tony DiCroce andKenneth Carpenter in 2001. Its discovery was made in the Poison Strip Sandstone Member of theCedar Mountain Formation in Grand County,Utah, United States. The generic name,Planicoxa, which means "flat hip", refers to the flat appearance of theilium formed by horizontal folding over of the postacetabular process (rear portion of the ilium), the defining characteristic of the genus;venenica, the specific name, is Latin for "poison" in reference to the Poison Strip Sandstone Member of the Cedar Mountain Formation where the discovery was made. The taxon is represented by a well-preserved ilium,femora,tibiae, andvertebrae, as well as other material. The femora are standard for ornithopods, but the ilium has a short, horizontal postacetabular process that is functionally an antitrochanter[clarification needed]. The discovery ofP. venenica added significant information to theBarremian-Albian fauna of the Cedar Mountain Formation.
A second species,P. depressa, was created by Carpenter and Wilson (2008) for material previously namedCamptosaurus depressus byCharles Gilmore in 1909. That material was collected from theLakota Formation near the town ofHot Springs, South Dakota. It too has the odd flat ilium formed by the horizontal postacetabular process. This species differs fromP. venenica in that the ilium is not as arched, has a thicker (more robust) preacetabular process (long, forward projection of the ilium), a shallower acetabular notch (hip-socket), and a proportionally narrowerbrevis shelf (a shelf for muscles on the inside of the rear part of the ilium). It is known from some vertebrae and two ilia. Isolated iguanodontid bones from the Lakota Formation probably belong to this species. In2011, it was assigned to its own genus,Osmakasaurus.[1]
