''Adamantisaurus'' ( ) is a poorly-known

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of titanosaurian

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 ...

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

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', ...

Period of what is now

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...

. It is only known from six tail

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates, Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characterist ...

e but, as a sauropod, it can be assumed that this dinosaur was a very large animal with a long neck and tail. Adamantisaurus by Ademar Pereira

Like many titanosaurians, ''Adamantisaurus'' is incompletely known, making its exact relationships difficult to establish. However, similarities have been noted with '' Aeolosaurus'' and the Bauru Group titanosaurian formerly known as the "Peiropolis titanosaur", now called ''

Trigonosaurus ''Trigonosaurus'' (meaning "triangle lizard" after Triangulo Mineiro, where it was found), is a genus of saltasaurid dinosaurs from the Maastrichtian Serra da Galga Formation of Brazil. The type species, ''Trigonosaurus pricei'', was first descr ...

''.

Description

As ''Adamantisaurus mezzalirai'' is only known from the anterior portion of the tail, relatively little is known about the anatomy of this species. It was probably a medium-sized titanosaur. In 2010 Gregory S. Paul estimated it to be roughly 13 meters (43 ft) long and 5 tonnes (5.5 short tons) in weight . However, in 2020 Molina-Pérez and Larramendi gave a larger estimation of 18 meters (60 ft) and 14.4 tonnes (15.8 short tons).

Discovery and naming

Although this animal's remains were first mentioned in print in 1959, it was not named until the description written by

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

ian

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...

s Rodrigo Santucci and Reinaldo Bertini in 2006. It was the first dinosaur named in that year. The type specimen, the only material known of the genus, consists of the second through seventh caudal vertebrae and two chevrons. ''Adamantisaurus'' is currently known only from the

Adamantina Formation The Adamantina Formation is a geological formation in the Bauru Basin of western São Paulo state, in southeastern Brazil. Its strata date back to the Late Cretaceous epoch of the Cretaceous Period, during the Mesozoic Era. The formation is par ...

of Brazil. The Adamantina Formation is part of the Bauru Group of

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

s. The

stratigraphy 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 ...

and exact age of the Bauru Group is still unsettled, but the Adamantina probably occurs somewhere between the

Turonian The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded ...

through early

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interv ...

stages of the

Period (93 to 70 million years ago). ''Adamantisaurus'' shares the Adamantina with fellow titanosaurian, '' Gondwanatitan''. ''Adamantisaurus'' is named after the

in the Brazilian state of

São Paulo São Paulo (, ; Portuguese for 'Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...

, where 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 preserved ...

was found and also incorporates the

Greek Greek may refer to: Greece 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 ...

word ''sauros'' meaning 'lizard', the most common suffix used in dinosaur names. The type and only species, ''Adamantisaurus mezzalirai'' is named in honor of Sérgio Mezzalira, the Brazilian

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, alt ...

who originally found the specimen and first mentioned it in print.

Classification

The phylogenetic relationship of ''Adamantisaurus'' has yet to be rigorously tested. However, it appears to be more derived than ''Malawisaurus'' based on the ball-and-socket articulation of the caudal vertebrae. All titanosaurs at least as derived as ''Malawisaurus'' are members of the clade Lithostrotia. Within that clade, however, its relationships are unclear. ''Adamantisaurus'' resembles ''Aeolosaurus'', a close relative of its contemporary ''Gondwanatitan'', in some respects. ''Adamantisaurus'' cannot be directly compared to ''Brasilotitan'', another genus found in the Adamantina Formation.

Description

Discovery and naming

Classification

References

Further reading