Describer

Calvo, Porfiri & Novas 2007

Time

Cretaceous Late Coniacian

Classification

Ornithischia Ornithopoda Iguanodontia [Euiguanodontia] [Elasmaria]

Diet

Herbivore

Fossilsite

Portezuelo Formation, 60 km NW from Neuquén city, on the west coast of the Mari Menuco lake, Neuquén, Neuquén Group, Neuquén Province, Patagonia, Argentina
Info

Etymology of Elasmaria

(Greek), thin plate. Phylogenetic definition of: Elasmaria is phylogenetically defined as Talenkauen santacrucensis, Macrogryphosaurus gondwanicus gen.nov., sp.nov., their most recent common ancestor plus all the descendants. Diagnosis of Elasmaria: Two unambiguous synapomorphies support the monophyly of Elasmaria: large basal euiguanodontian with well-developed epipophyses on the third cervical and presence of thin ossified plates on thorax.

Holotype

MUCPv-321. The specimen was found articulated with the cervical and dorsal series in straight position with the ventral zone upward. Only post-cranial materials are preserved, 8 postaxial cervicals, 14 dorsals, 6 sacrals and 16 caudals, cervical and dorsal ribs, both ilia, pubes, and ischia, one sternum, and 4 thoracic plate.

Etymology

Macrogryphosaurus, from Greek macro, big; grypho, enigmatic; saurus; lizard; and gondwanicus in reference to the Gondwana continent.

Diagnosis

Triradiate sternum with the anterior border tribranched, two laterally placed and outward directed and one centrally placed smaller and forwardly directed. Sternal ribs flattened, twisted and distally expanded. Last dorsal with well-developed hyposphene. A thin plate-like is located in front of the sterna. Together with these autapomorphies this Elasmarian euiguanodontian differs from Talenkauen santacrucensis by having the pubic peduncle of ilium less developed, a more acute angle between the anterior process of ilium and the pubic peduncle, the acetabular cavity slightly marked. Ten cervical vertebrae, fourteen dorsal vertebrae, epipophyses on the 3rd cervical placed over the distal end of the postzygapophyses and posteriorly projected.