''Macrogryphosaurus'' (meaning "big enigmatic lizard") is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

elasmaria Elasmaria is a clade of Ornithopoda, ornithopods known from Cretaceous deposits in the former Gondwana (South America, Antarctica, Australia, and possibly Africa) that contains many bipedal ornithopods that were previously considered Hypsilophodo ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Coniacian The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series and spans the time between 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by ...

age

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cret ...

Sierra Barrosa Formation The Sierra Barrosa Formation is a geologic formation of the Neuquén Basin in the northern Patagonian provinces of Mendoza Province, Mendoza and Neuquén Province, Neuquén. The formation dates to the Late Cretaceous, Coniacian, middle to late Con ...

(

Neuquén Group The Neuquén Group is a geologic unit, group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period. It overlies the older Lohan Cura Formation and ...

) of

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

. It was described by Jorge Calvo and colleagues in 2007, with ''M. gondwanicus'' as the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

and only species.

Discovery and naming

In May 1999, during field work at Mari Menuco Lake,

(sixty kilometres northwest of

Neuquén Neuquén (; ) is the capital city of the Argentine province of Neuquén and of the Confluencia Department, located in the east of the province. It occupies a strip of land west of the confluence of the Limay and Neuquén rivers which form t ...

) conducted by the

National University of Comahue The National University of Comahue (, UNCNavarro, Fernando A. ''. Tremédica, Asociación Internacional de Traductores y Redactores de Medicina y Ciencias Afines/UNCoPortal de Prensa de la Uncoma, Universidad Nacional del Comahue'/Uncoma) is an ...

, an articulated, nearly complete dinosaur skeleton was discovered and excavated. It was brought to the attention of the palaeontologists by young boy Rafael Moyano, who had discovered it.Poropat, S. F. The Winston Churchill Memorial Trust of Australia.
/ref> Originally reported to hail from the Portezuelo Formation of the

, its locality was later revised to be in the

of the same geologic group. This unit is dated to the

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone has been alive or something has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

. Noted for bony plates on its thorax, it was identified as a large species of ornithopod. 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 Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

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. The preservation of the fossil was described by Dr. Stephen F. Poropat as "amazing" in nature. Subsequent research has not referred any other specimens to the species. However, in 2016, a study was published on MAU-Pv-PH-458, a fragmentary dorsal neural arch from the

Plottier Formation The Plottier Formation is a geologic formation that outcrops in the Argentine Patagonian provinces of Río Negro and Neuquén. It is the younger of two formations belonging to the Río Neuquén Subgroup within the Neuquén Group of the Neuquén ...

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 Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithost ...

location, though it lived at a slightly earlier time. Other indeterminate ornithopod specimens from Argentina similarly indicate animals of similar size to the

taxon In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

. ''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.

Description

''Macrogryphosaurus'' has been noted for its large size compared to other South American ornithopods. It has been estimated to have been around in length, though the only known individual may not have been fully grown. Gregory S. Paul estimated the length of this specimen at in length and in body mass. As such, it is the largest species of South American

ornithopod Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively sm ...

outside of

Hadrosauridae Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fam ...

, and the largest species of elasmarian. Approaching the size of many more derived iguanodontian ornithopods, it is, compared to these derived taxa, much more graceful and lightly built in form. One of the most remarked upon features of the taxon is its mineralized thoracic plates, also referred to as intercostal plates. These are a series of plates along the side of the torso, shared with a handful of other ornithischians such as ''

Talenkauen ''Talenkauen'' is a genus of Basal (phylogenetics), basal iguanodont dinosaur from the Campanian or Maastrichtian age of the Late Cretaceous Cerro Fortaleza Formation, formerly known as the Pari Aike Formation of Patagonian Lake Viedma, in the Ma ...

'', ''

Thescelosaurus ''Thescelosaurus'' ( ) is a genus of Ornithischia, ornithischian dinosaur that lived during the Late Cretaceous period (geology), period in western North America. It was named and described in 1913 by the Paleontology, paleontologist Charles W. G ...

'', and ''

Hypsilophodon ''Hypsilophodon'' (; meaning "high-crested tooth") is a neornithischian dinosaur genus from the Early Cretaceous period of England. It has traditionally been considered an early member of the group Ornithopoda, but recent research has put this ...

''. Along with a fused, birdlike sternum, its short torso would have been rather stiff in nature. This, alongside its relatively elongate neck and

coelurosaur Coelurosauria (; from Greek, meaning "hollow-tailed lizards") is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. Coelurosauria is a subgroup of theropod dinosaurs that includes compsognathids, ty ...

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

Classification

Phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analysis indicates that it is related to ''

'', and Calvo and colleagues proposed a new

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

Elasmaria Elasmaria is a clade of Ornithopoda, ornithopods known from Cretaceous deposits in the former Gondwana (South America, Antarctica, Australia, and possibly Africa) that contains many bipedal ornithopods that were previously considered Hypsilophodo ...

, for the two genera. The

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

below results from analysis by Herne ''et al.'', 2019.

References

External links

* * {{Taxonbar, from=Q138604 Elasmaria Dinosaur genera Coniacian dinosaurs Fossil taxa described in 2007 Taxa named by Fernando Novas Dinosaurs of Argentina