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

Re: New Deinocheirus specimens found, indicating basal ornithomimosaur

The illustration does NOT match the new discovery. Deinocheirus does not
simply look like a larger, heavier Gallimimus.

On Mon, November 4, 2013 7:41 pm, Ben Creisler wrote:
> From: Ben Creisler
> bcreisler@gmail.com
> For a much more detailed description of the find and the presentation
> of the new Deinocheirus material, see Brian Switek's latest posting
> for Laelaps:
> http://news.nationalgeographic.com/news/2013/11/131104-dinosaur-hands-arms-body-mongolia/
> On Mon, Nov 4, 2013 at 10:21 AM, Ben Creisler <bcreisler@gmail.com> wrote:
>> From: Ben Creisler
>> bcreisler@gmail.com
>> Now that the embargo on the SVP meeting abstracts has expired a number
>> of notable items can be mentioned, pending formal scientific papers.
>> Technical Session IX (Friday, November 1, 2013, 9:30 AM)
>> LEE, Yuong-Nam, Korea Institute of Geoscience and Mineral Resources,
>> Daejeon,
>> Korea, Republic of (South); BARSBOLD, Rinchen, Paleontological Center,
>> Ulaanbaatar,
>> Mongolia; CURRIE, Philip, University of Alberta, Edmonton, AB, Canada;
>> KOBAYASHI, Yoshitsugu, Hokkaido University Museum, Sapporo, Japan; LEE,
>> Hang-
>> Jae, Korea Institute of Geoscience and Mineral Resources, Daejeon,
>> Korea, Republic of
>> (South)
>> The holotype of Deinocheirus mirificus was collected by the
>> Polish-Mongolian Palaeontological Expedition at Altan Uul III in 1965.
>> Because the holotype was known mainly on the basis of giant forelimbs
>> with scapulocoracoids, Deinocheirus has remained one of the most
>> mysterious dinosaurs. Two new specimens of Deinocheirus were
>> discovered in the Nemegt Formation of Altan Uul IV in 2006 and Bugin
>> Tsav in 2009 by members of the Korea-Mongolia International Dinosaur
>> Expedition (KID). Except for the skull, middle dorsal and most of the
>> distal caudal vertebrae, the right forelimb, left manus, and both
>> pedes, the remaining parts of the skeleton (Mongolian Paleontological
>> Center [MPC]-D 100/127) including a left forelimb clearly identifiable
>> as Deinocheirus were collected. The humerus (993 mm in length) is
>> longer than the 938 mm humerus of the holotype. The Altan Uul IV
>> specimen (MPC-D 100/128) is a subadult Deinocheirus (approximately 72%
>> of MPC-D 100/127), which consists of post-cervical vertebrae, ilia,
>> ischia, and hind limbs. Both specimens provide important
>> paleontological evidence for exact postcranial reconstruction of
>> Deinocheirus mirificus. Cladistic analysis indicates that Deinocheirus
>> is a basal member of Ornithomimosauria, but many new unique skeletal
>> features appear to be quite different from other ornithomimosaurs.
>> These include extreme pneumaticity of tall, anterodorsally oriented
>> distal dorsal neural spines (7~8 times taller than centrum height)
>> with basal webbing, fused sacral neural spines forming a midline plate
>> of bone that extends dorsally up to 170% of the height of the ilium,
>> ventrally keeled sacral centra, a well-developed iliotibialis flange,
>> a posterodorsally projecting posterior iliac blade with a concave
>> dorsal margin, a steeply raised anterior dorsal margin of the ilium,
>> an anteriorly inclined brevis shelf, vertically well-separated iliac
>> blades above the sacrum, an completely enclosed pubic obturator
>> foramen, triangular pubic boot in distal view, vertical ridges on
>> anterior and posterior edges of medial surface of the femoral head,
>> and a robust femur that is longer than tibiotarsus. These features
>> suggest that Deinocheirus (unlike other ornithomimosaurs) was not a
>> fast-running animal, but a bulky animal with a heavily built pelvis
>> and hind limbs. However, the dorsal ribs are tall and relatively
>> straight, suggesting that the animal was narrow-bodied. A large number
>> of gastroliths (>1100 ranging from 8 to 87 mm) were collected from the
>> abdominal region of MPC-D 100/127, suggesting Deinocheirus was an
>> herbivore.
>> ==

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
Fax: 301-314-9661

Faculty Director, Science & Global Change Program, College Park Scholars
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