''Mapusaurus'' ( Earth 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 ...
of giant
carcharodontosaurid carnosauria
Carnosauria is an extinct group of carnivorous theropod dinosaurs that lived during the Jurassic and Cretaceous periods.
While Carnosauria was historically considered largely synonymous with Allosauroidea, some recent studies have revived Ca ...
n
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 ...
that lived in
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 ...
during the
Turonian
The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...
age 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 ...
.
Discovery
''Mapusaurus'' was excavated between 1997 and 2001, by the Argentinian-Canadian Dinosaur Project, from an exposure of the
Huincul Formation
The Huincul Formation is a geologic formation of Late Cretaceous (Cenomanian to Turonian, Early Turonian) age of the Neuquén Basin that outcrops in the Mendoza Province, Mendoza, Rio Negro Province, Río Negro and Neuquén Provinces of northern ...
(late
Cenomanian
The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...
–
Turonian
The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...
) at Cañadón del Gato. It was described and named by
paleontologists Rodolfo Coria and
Phil Currie in 2006.
The name ''Mapusaurus'' is derived from the
Mapuche
The Mapuche ( , ) also known as Araucanians are a group of Indigenous peoples of the Americas, Indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging e ...
word ''Mapu'', meaning 'of the Land' or 'of the Earth' and the
Greek
Greek may refer to:
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group
*Greek language, a branch of the Indo-European language family
**Proto-Greek language, the assumed last common ancestor of all kno ...
''sauros'', meaning '
lizard
Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...
'. The
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
, ''Mapusaurus roseae'', is named for both the
rose
A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...
-colored rocks, in which the fossils were found and for
Rose Letwin, who sponsored the expeditions which recovered these fossils.
The designated
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 ...
for the
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 ...
and
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
, ''Mapusaurus roseae'', is an isolated right nasal (MCF-PVPH-108.1, Museo Carmen Funes, Paleontología de Vertebrados, Plaza Huincul, Neuquén). Twelve paratypes have been designated, based on additional isolated skeletal elements. Taken together, the many individual elements recovered from the ''Mapusaurus'' bone bed represent most of the skeleton.
Description

''Mapusaurus'' was a large theropod, but slightly smaller in size than its close relative ''
Giganotosaurus
''Giganotosaurus'' ( ) is a genus of large theropod dinosaur that lived in what is now Argentina, during the early Cenomanian age of the Late Cretaceous period (geology), period, approximately 99.6 to 95 million years ago. The holotype specim ...
'', with the largest specimen measuring around long and weighing up to .
It has been determined that ''Mapusaurus'' was diagnosed on autapomorphies, or unique traits, in regions of the skeleton that ''Giganotosaurus'' does not preserve. In terms of autapomorphic features, ''Mapusaurus'' only differs from ''Giganotosaurus'' in lacking a second opening on the middle
quadrate, and in some details of the topology of the nasal rugosities. Despite this, ''Mapusaurus'' differs from ''Giganotosaurus'' in a variety of both cranial and postcranial characters, and the fact that said characters are not autapomorphic is not considered suggestive of a potential genus synonymy.
Paleobiology

The
fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...
remains of ''Mapusaurus'' were discovered in a
bone bed
A bone bed is any Geology, geological stratum or deposition (geology), deposit that contains bones of whatever kind. Inevitably, such deposits are Sedimentary rock, sedimentary in nature. Not a formal term, it tends to be used more to describe esp ...
containing at least seven to possibly up to nine individuals of various
growth stages.
Coria and Currie speculated that this may represent a long term, possibly coincidental accumulation of carcasses (some sort of
predator trap) and may provide clues about ''Mapusaurus'' behavior.
Other known
theropod
Theropoda (; from ancient Greek , (''therion'') "wild beast"; , (''pous, podos'') "foot"">wiktionary:ποδός"> (''pous, podos'') "foot" is one of the three major groups (clades) of dinosaurs, alongside Ornithischia and Sauropodom ...
bone beds and fossil graveyards include those of
dromaeosaurid
Dromaeosauridae () is a family (biology), family of feathered coelurosaurian Theropoda, theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous period (geology), Period. The name Drom ...
s ''
Deinonychus
''Deinonychus'' ( ; ) is a genus of Dromaeosauridae, dromaeosaurid Theropoda, theropod dinosaur with one described species, ''Deinonychus antirrhopus''. This species, which could grow up to long, lived during the early Cretaceous Period (ge ...
'' and ''
Utahraptor'', those of ''
Allosaurus
''Allosaurus'' ( ) is an extinct genus of theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic period ( Kimmeridgian to late Tithonian ages). The first fossil remains that could definitively be ascribed to th ...
'' from the
Cleveland-Lloyd Dinosaur Quarry
Jurassic National Monument, at the site of the Cleveland-Lloyd Dinosaur Quarry, well known for containing the densest concentration of Jurassic dinosaur fossils ever found, is a paleontological site located near Cleveland, Utah, in the San Rafa ...
of
Utah
Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...
, and those of
tyrannosaurids ''
Teratophoneus
''Teratophoneus'' ("monstrous murderer"; Greek: ''teras'', "monster" and ''phoneus'', "murderer") is a genus of Tyrannosaurinae, tyrannosaurine Theropoda, theropod dinosaur that lived during the late Campanian age of the Late Cretaceous period, ...
'', ''
Albertosaurus
''Albertosaurus'' (; meaning "Alberta lizard") is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million yea ...
'' and ''
Daspletosaurus''.

Paleontologist Rodolfo Coria, of the
Museo Carmen Funes, contrary to his published article, repeated in a press-conference earlier suggestions that this congregation of fossil bones may indicate that ''Mapusaurus'' like ''Giganotosaurus'' also hunted in groups and worked together to take down large prey, such as the immense
sauropod
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
''
Argentinosaurus
''Argentinosaurus'' (meaning "lizard from Argentina") is a genus of giant sauropod dinosaur that lived during the Late Cretaceous Period (geology), period in what is now Argentina. Although it is only known from fragmentary remains, ''Argentinos ...
''.
If so, this would be the first substantive evidence of gregarious behavior by large theropods other than ''
Tyrannosaurus rex
''Tyrannosaurus'' () is a genus of large theropoda, theropod dinosaur. The type species ''Tyrannosaurus rex'' ( meaning 'king' in Latin), often shortened to ''T. rex'' or colloquially t-rex, is one of the best represented theropods. It live ...
'', although whether they might have hunted in organized packs (as wolves and lions do) or simply attacked in a mob, is unknown. The authors interpreted the
depositional environment
In geology, depositional environment or sedimentary environment describes the combination of physical, chemical, and biological processes associated with the deposition of a particular type of sediment and, therefore, the rock types that will b ...
of the Huincul Formation at the Cañadón del Gato locality as a freshwater paleochannel deposit, "laid down by an ephemeral or seasonal stream in a region with arid or semi-arid climate".
This bone bed is especially interesting, in light of the overall scarcity of fossilized bone within the Huincul Formation. An ontogenetic study by Canale et al. (2014)
found that ''Mapusaurus'' displayed heterochrony, an evolutionary condition in which the animals may retain an ancestral characteristic during one stage of their life, but lose it as they develop. In ''Mapusaurus'', the maxillary fenestrae are present in younger individuals, but gradually disappear as they mature.
Classification
Cladistic
Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...
analysis carried out by Coria and Currie definitively showed that ''Mapusaurus'' is nested within the
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 ...
Carcharodontosauridae. The authors noted that the structure of the
femur
The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg.
The Femo ...
suggests a closer relationship with ''Giganotosaurus'' than either
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 ...
shares with ''
Carcharodontosaurus''. They created a new
monophyletic
In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria:
# the grouping contains its own most recent co ...
taxon based on this relationship, the
subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...
Giganotosaurinae, defined as all carcharodontosaurids closer to ''Giganotosaurus'' and ''Mapusaurus'' than to ''Carcharodontosaurus''. They tentatively included the genus ''
Tyrannotitan'' in this new subfamily, pending publication of more detailed descriptions of the known specimens of that form.
In their 2022 description of the large carcharodontosaurine ''
Meraxes'', Canale et al. recovered the following relationships for ''Mapusaurus'' and the Giganotosaurini.
In his 2024 review of theropod relationships, Cau recovered similar results, with ''
Tyrannotitan'' as the
sister taxon
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
to the clade formed by ''Mapusaurus'' and ''Giganotosaurus''. His results are displayed in 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:
Paleoecology

As previously mentioned, the Huincul Formation is thought to represent an arid environment with ephemeral or seasonal streams. The age of this formation is estimated at 97 to 93.5 MYA.
[Huincul Formation]
at Fossilworks
Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world.
History
Fossilworks was cr ...
.org The dinosaur record is considered sparse here. ''Mapusaurus'' shared its environment with the
sauropods
Sauropoda (), whose members are known as sauropods (; from '' sauro-'' + '' -pod'', 'lizard-footed'), is a clade of saurischian ('lizard-hipped') dinosaurs. Sauropods had very long necks, long tails, small heads (relative to the rest of their b ...
''
Argentinosaurus
''Argentinosaurus'' (meaning "lizard from Argentina") is a genus of giant sauropod dinosaur that lived during the Late Cretaceous Period (geology), period in what is now Argentina. Although it is only known from fragmentary remains, ''Argentinos ...
'' (one of the largest sauropods, if not the largest), ''
Choconsaurus'', ''
Chucarosaurus'' and ''
Cathartesaura''. Two other giant carcharodontosaurids, ''
Meraxes'' and ''
Taurovenator'', were found in the same formation, but in older rocks than ''Mapusaurus'', so they likely were not coevals.
The
abelisaurid theropods ''
Skorpiovenator'' and ''
Ilokelesia'' also lived in the region.
Fossilized pollen indicates a wide variety of plants was present in the Huincul Formation. A study of the El Zampal section of the formation found
hornwort
Hornworts are a group of non-vascular Embryophytes (land plants) constituting the division Anthocerotophyta (). The common name refers to the elongated horn-like structure, which is the sporophyte. As in mosses and liverworts, hornworts have a ...
s,
liverwort
Liverworts are a group of non-vascular land plants forming the division Marchantiophyta (). They may also be referred to as hepatics. Like mosses and hornworts, they have a gametophyte-dominant life cycle, in which cells of the plant carry ...
s,
fern
The ferns (Polypodiopsida or Polypodiophyta) are a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular, i.e., having specialized tissue ...
s,
Selaginellales
''Selaginella'', also known as spikemosses or lesser clubmosses, is a genus of lycophyte. It is usually treated as the only genus in the family Selaginellaceae, with over 750 known species.
This family is distinguished from Lycopodiaceae (the ...
, possible
Noeggerathiales,
gymnosperm
The gymnosperms ( ; ) are a group of woody, perennial Seed plant, seed-producing plants, typically lacking the protective outer covering which surrounds the seeds in flowering plants, that include Pinophyta, conifers, cycads, Ginkgo, and gnetoph ...
s (including
gnetophytes and
conifer
Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...
s), and
angiosperm
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed within a fruit ...
s (flowering plants), in addition to several pollen grains of unknown affinities.
The Huincul Formation is among the richest Patagonian vertebrate associations, preserving fish including
dipnoans and
gar,
chelid turtles,
squamate
Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest Order (biology), order of reptiles; most members of which are commonly known as Lizard, lizards, with the group also including Snake, snakes. With over 11,991 species, it i ...
s,
sphenodonts,
neosuchian crocodilian
Crocodilia () is an Order (biology), order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorp ...
s, and a wide variety of dinosaurs.
Vertebrates are most commonly found in the lower, and therefore older, part of the formation.
References
External links
Meat-Eating Dinosaur Was Bigger Than T. Rex.National Geographic News
*
. Mike Taylor. The Dinosaur FAQ. August 27, 2002. (Named as Unnamed Argentinian Carcharodontosaurine)
* "
nd the Largest Theropod is... http://dml.cmnh.org/2003Jul/msg00355.html. The Dinosaur Mailing List Archives. Retrieved March 21, 2010 (Named as Undescribed Carcharodontosaurine)
{{Taxonbar, from=Q131176
Carcharodontosauridae
Dinosaur genera
Turonian dinosaurs
Huincul Formation
Fossil taxa described in 2006
Taxa named by Rodolfo Coria
Taxa named by Philip J. Currie
Dinosaurs of Argentina