New Deinocheirus specimens found

Adam Khor · 05-11-2013 1:32am #1

Finally, the most mysterious of all mystery dinos reveals its secrets... and its weirder than anyone imagined.

No official press release yet, and all pictures in the web thus far are speculative (no official reconstruction has been released), but here's the abstract of the paper:

"Abstract: 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 (7~8times 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 anteriordorsal margin of the ilium, an anteriorly inclined brevis shelf, vertically well-separatediliac 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."

In short, it appears that Deinocheirus was a slow-moving 11-12 meter long primivie ornithomimosaur, taller than Therizinosaurus and with a weird, forward-facing back sail (!!!).

More to be revealed soon, hopefully...

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