Macrogryphosaurus

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Macrogryphosaurus
Temporal range:
Ma
↓
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: †Ornithischia
Clade: †Neornithischia
Clade: †Ornithopoda
Clade: †Elasmaria
Genus: †Macrogryphosaurus
Calvo et al. 2007
Species:
†M. gondwanicus
Binomial name
†Macrogryphosaurus gondwanicus
Calvo et al. 2007

Macrogryphosaurus (meaning "big enigmatic lizard") is a

Upper Cretaceous Sierra Barrosa Formation (Neuquén Group) of Argentina in Patagonia. It was described by Jorge Calvo and colleagues in 2007, with M. gondwanicus as the type
and only species.

Discovery and naming

Satellite image of the terrain of the Neuquén Group, the geologic unit Macrogryphosaurus is from

In May 1999, during field work at

age of the Late Cretaceous. Noted for bony plates on its thorax, it was identified as a large species of ornithopod.[1]

The species would be described and named Macrogryphosaurus gondwanicus in 2007, in a study authored by Jorge O. Calvo, Juan D. Porfiri, and Fernando E. Novas. Its generic name was derived from the Greek macro, meaning large, grypho, meaning enigmatic, and saurus, meaning lizard. The specific epithet gondwanicus refers to the ancient continent of Gondwana.[1] The holotype specimen, MUCPv-32, consists of an essentially complete set of vertebra, a number of ribs, four mineralized thoracic plates, both sides of the pectoral girdle, and a sternum. The individual is considered to have been an adult.[1][3] The preservation of the fossil was described by Dr. Stephen F. Poropat as "amazing" in nature.[2]

Subsequent research has not referred any other specimens to the species.[3] However, in 2016, a study was published on MAU-Pv-PH-458, a fragmentary dorsal neural arch from the Plottier Formation of northern Argentina. The bone is the northernmost record of an ornithopod in South America. It was not determined to belong to a Macrogryphosaurus, but noted to be from an animal of similar size and anatomy, and from approximately the same geographic and stratigraphic location, though it lived at a slightly earlier time.[4] Other indeterminate ornithopod specimens from Argentina similarly indicate animals of similar size to the taxon.[5][6] M. gondwanicus received a complete osteology in 2020, a study published in Cretaceous Research by Sebastián Rozadilla, Penélope Cruzado-Caballero, Jorge O. Calvo. This described the anatomy of the species in much more thoroughly and investigating its classification and biomechanics under a more modern lens. They considered the genus to be of importance, due to being the largest known elasmarian species, and for the completeness of its known remains, informing on the anatomy of the group.[3]

Description

Size comparison

Macrogryphosaurus has been noted for its large size compared to other South American ornithopods. It has been estimated to have been around 6 metres (20 ft) in length, though the only known individual may not have been fully grown.

coelurosaur-like tail, gave it a rather unique form compared to that documented in other ornithischian dinosaurs.[3]

Classification

Phylogenetic analysis indicates that it is related to Talenkauen, and Calvo and colleagues proposed a new clade, Elasmaria, for the two genera.[1]

The cladogram below results from analysis by Herne et al., 2019.[8]

Ornithischia

References

  1. ^ a b c d e Calvo, Jorge O.; Porfiri, Juan D.; Novas, Fernando E. (2007). "Discovery of a new ornithopod dinosaur from the Portezuelo formation (Upper Cretaceous), Neuquen, Patagonia, Argentina". Arquivos do Museu Nacional, Rio de Janeiro. 65 (4): 471–483.
  2. ^ a b Poropat, S. F. The Winston Churchill Memorial Trust of Australia.
  3. ^
    S2CID 213679041
    .
  4. doi:10.1016/j.annpal.2016.02.003
    .
  5. S2CID 53407321
    .
  6. hdl:11336/71315
    .
  7. OCLC 985402380
    .
  8. doi:10.1017/jpa.2018.95
    .

External links
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