Master's Theses

Department

Biology

Degree Name

Master of Science (MS)

Abstract

The Early Cretaceous (Albian) Kiowa Shale of Clark County, Kansas consists mainly of dark gray shale with occasional limestone deposits that represent a near shore environment. Faunal lists have been published based on fragmentary materials; however, few individual specimens have been described in the last 100 years. Here an unusual plesiosaur specimen (KUVP 16375) is described. The specimen consists of 17 cervical vertebrae: 10 articulated and 7 disarticulated. Some of the vertebrae are uniquely preserved with an atypical ventral excavation not present in known plesiosaur vertebrae. It is not clear whether or not this character is of phylogenetic or diagnostic significance. Many vertebrae lack distinct rib facets. Neural spines are absent from all elements of the specimen. A number of elements possess well-defined zygapophyses and neural canals. Foramina subcentralia are present in the ventral surface of plesiosaur cervical vertebrae but appear to be absent in many of the vertebrae of KUVP 16375. The specimen is described and interpreted as a polycotylid. The specimen is then compared to other plesiosaurs including other polycotylids and its phylogenetic position is analyzed. Character matrices and the physical description allowed referral of the specimen to the Polycotylidae. This family consists of short-necked, large-headed plesiosaurs and is represented by small sample sizes from the Kiowa Shale. Determination of the genus and species is not made at this time.

Keywords

plesiosaur, polycotylid, cervical vertebrae, Dolichorhynchops, Trinacromerum

Advisor

Dr. S. Christopher Bennett

Date of Award

Spring 2014

Document Type

Thesis

Rights

© The Author(s)

Comments

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