The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas

A new polycotylid plesiosaur (Reptilia; Sauropterygia) from the Greenhorn Limestone (Upper Cretaceous; lower upper Cenomanian), Black Hills, South Dakota
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Published:January 01, 2007
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CiteCitation
Bruce A. Schumacher, 2007. "A new polycotylid plesiosaur (Reptilia; Sauropterygia) from the Greenhorn Limestone (Upper Cretaceous; lower upper Cenomanian), Black Hills, South Dakota", The Geology and Paleontology of the Late Cretaceous Marine Deposits of the Dakotas, James E. Martin, David C. Parris
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A plesiosaur skeleton from the base of the Greenhorn Limestone (lower upper Cenomanian), western South Dakota, represents a new taxon tentatively referred to the Polycotylidae. The specimen possesses a number of features in common with the Polycotylidae, including an exceptionally elongate muzzle and mandibular symphysis, lack of a parietal foramen, homodont dentition, and faint striae only on the medial side of teeth. However, the palate and limb morphologies differ with respect to Polycotylidae as currently known. The pterygoids are united along their midline anterior to the parasphenoid, lacking an anterior interpterygoid vacuity. The preserved parasphenoid is relatively robust, possesses a...
- Black Hills
- Butte County South Dakota
- Cenomanian
- Chordata
- cladistics
- Cretaceous
- Diapsida
- Greenhorn Limestone
- Mesozoic
- morphology
- new taxa
- North America
- phylogeny
- Plesiosauria
- Reptilia
- Sauropterygia
- skeletons
- skull
- South Dakota
- taxonomy
- Tetrapoda
- United States
- upper Cenomanian
- Upper Cretaceous
- Vertebrata
- Western Interior
- Western Interior Seaway
- Polycotylidae
- Fruitdale South Dakota
- Pahasapasaurus haasi