[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Sauroposeidon in the Cloverly!

D'Emic also sinks *Paluxysaurus jonesi* as a junior synonym of *Sauroposeidon 
proteles*, and *Rugocaudia cooneyi* as a nomen dubium.

> Date: Tue, 26 Jun 2012 15:14:26 -0400
> From: tholtz@umd.edu
> To: dinosaur@usc.edu
> Subject: Sauroposeidon in the Cloverly!
> D'Emic, M.D., & B.Z. Foreman. 2012. The beginning of the sauropod dinosaur 
> hiatus in North America: insights from the Lower
> Cretaceous Cloverly Formation of Wyoming. Journal of Vertebrate Paleontology 
> 32(4):883-902
> DOI: 10.1080/02724634.2012.671204
> We redescribe and present newly excavated sauropod material from the Lower 
> Cretaceous Cloverly Formation of Wyoming that we refer to
> the titanosauriform Sauroposeidon proteles. In contrast to previous 
> hypotheses that it was a brachiosaurid, we assert that
> Sauroposeidon is a member of the Somphospondyli on the basis of numerous 
> features. Thus, the mid-Cretaceous disappearance of
> sauropods from the North American fossil record concerned both brachiosaurids 
> and somphospondylans. We find claims for titanosaurs
> in the Early Cretaceous of North America to be unsubstantiated. The latest 
> register of Sauroposeidon and other Early Cretaceous
> North American sauropods (before the 'sauropod hiatus') occurs in or below 
> the coastal units marking transgression of the Western
> Interior Seaway, whereas many ecologically disparate dinosaur groups are 
> present both below and above this boundary in the same
> geologic units that sauropods are found in. The presence of these 
> through-ranging groups with sauropods before and after sauropod
> absence suggests that appropriate sauropod-bearing environments were present 
> into the Late Cretaceous, implying that the
> disappearance of sauropods is not attributable to taphonomic or sampling 
> bias. Furthermore, field observations of the Cloverly
> Formation indicate that Cretaceous pre-hiatus sauropods inhabited 
> near-coastal environments, which were abundant in the western
> United States well after the start of the hiatus. The start of the sauropod 
> hiatus is interpreted as the result of a genuine
> continent-wide extinction, coincident with the appearance of (and perhaps 
> attributable to competition with) advanced ornithischian
> herbivores, decrease in habitat due to the incursion of the Western Interior 
> Seaway, or both.
> Thomas R. Holtz, Jr.
> Email: tholtz@umd.edu Phone: 301-405-4084
> Office: Centreville 1216
> Senior Lecturer, Vertebrate Paleontology
> Dept. of Geology, University of Maryland
> http://www.geol.umd.edu/~tholtz/
> Fax: 301-314-9661
> Faculty Director, Science & Global Change Program, College Park Scholars
> http://www.geol.umd.edu/sgc
> Fax: 301-314-9843
> Mailing Address: Thomas R. Holtz, Jr.
> Department of Geology
> Building 237, Room 1117
> University of Maryland
> College Park, MD 20742 USA