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Re: New Deinocheirus specimens found, indicating basal ornithomimosaur



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)
> NEW SPECIMENS OF DEINOCHEIRUS MIRIFICUS FROM THE LATE CRETACEOUS OF MONGOLIA
> 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.
>
>
> ==