''Itapeuasaurus'' (meaning "Itapeua lizard") is a genus of

rebbachisaurid Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, Europe and possibly Central Asia. Taxonomy In 1990 sauropod specialist Jack McIntosh included t ...

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 bo ...

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

Alcântara Formation The Alcântara Formation is a geological formation in northeastern Brazil whose strata date back to the Cenomanian of the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divide ...

(Itapecuru Group) of

Maranhão Maranhão () is a state in Brazil. Located in the country's Northeast Region, it has a population of about 7 million and an area of . Clockwise from north, it borders on the Atlantic Ocean for 2,243 km and the states of Piauí, Tocantins and ...

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 ...

. The type and only species is ''Itapeuasaurus cajapioensis''. It would have been around to when fully grown and ''Itapeuasaurus'' is the most complete

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

-aged

diplodocoid Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like ''Supersaurus'', ''Diplodocus'', ''Apatosaurus'', and ''Amphicoelias''. Most had very long necks and long, ...

known from

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 southe ...

and it is also the first reported Cenomanian-aged

discovered in South America.

Discovery and naming

In November 2014,

fisherman A fisher or fisherman is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are about 38 million commercial and subsistence fishers and fish farmers. Fishers may be professional or recreati ...

Carlos Wagner Silva discovered a

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 ...

ised

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

on the beach at Itapeua. In May 2015,

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 fossi ...

Manuel Alfredo Medeiros and his students were sent in and they secured several bones, including the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

, UFMA. 1.10.1960a, which consists of six

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 characteristic ...

e, and a

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...

containing around six to seven vertebrae, a humerus and a partial ischium - the largest preserved vertebra reached up to . Because the location where the holotype was found is an intertidal area, excavating the holotype was very hard and could only be excavated around four hours a day during each daily

tidal cycle Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables can ...

. In 2019, the species ''Itapeuasaurus cajapioensis'' was named and described.

Phylogeny

Lindoso ''et al.'', (2019) placed ''Itapeuasaurus'' in the

Nigersaurinae Rebbachisaurinae is a subfamily within the family Rebbachisauridae, defined to include ''Rebbachisaurus garasbae'' and exclude '' Limaysaurus tessonei''. It was first proposed as a rank by Jose Bonaparte Jose is the English transliteration of ...

, as the sister taxon to ''

Demandasaurus ''Demandasaurus'' (meaning " Demanda lizard") is a genus of rebbachisaurid sauropod dinosaur from early Cretaceous (late Barremian – early Aptian stage) deposits of Spain. ''Demandasaurus'' is known from an incomplete but associated skeleton t ...

''.

References

Rebbachisaurids Cenomanian life Late Cretaceous dinosaurs of South America Cretaceous Brazil Fossil taxa described in 2019 {{sauropodomorph-stub