Posts Tagged ‘alvarezsaurid’
Name: »slim thighs«
Length: 1,3 m
Height: 50 cm
Weight: 5 kg
Time: Cretaceous (100 – 95 MYA)
Location: South America (Argentina)
Alnashetri cerropoliciensis (pronounced: al-nuh-sheh-try) is a genus of alvarezsauroid coelurosaurian theropod known from the early Late Cretaceous (Cenomanian to Turonian stage) of La Buitrera, Río Negro Province, Argentina. Its remains were discovered in Candeleros Formation. The genus Alnashetri means “slim/slender thighs” in Günün-a-künna , the northern dialect group of the Tehuelche , the ancient inhabitants of the region. The species name refers to a town near the site La Buitrera : Cerro Policia in the Argentine province of Río Negro . Alnashetri’s estimated height is half a meter. It was a warm-blooded, feathered bipedal animal.
The paleontologist Sebastian Apesteguía introduced a carnivore with beak and feathers that was found at the site The Buitrera, in the province of Black River. It is the oldest of alvarezsaurids.
The “Alnashetri cerropoliciensis” lived 95 million years ago and was found at the site The Buitrera, measured 50 inches long and 20 high. It is the oldest known alvarezsaurid so far, a species of carnivorous dinosaurs related to birds.
The specimen was found by the exploration team of Natural History Foundation Félix de Azara, Maimonides University, and American Field Museum in Chicago, under the leadership of Apesteguía, research fellow of CONICET, and resident of Chicago paleontologist Danish Peter Makovicky.
A new coelurosaurian theropod, Alnashetri cerropoliciensis, is reported here based on articulated hind limbs of a single individual discovered at the locality of La Buitrera (Candeleros Formation, Cenomanian–Turonian), Río Negro Province, Argentina. The new taxon
differs from other coelurosaurs in the possession of a low ridge that separates the rostral tibial surface from the outer face of the lateral malleolus, and which extends proximally beyond the tip of the ascending process of the astragalus, and in the possession of ventral
notches on the hemicondyles of the distal articulations on pedal phalanges III-1 and III-2. Alnashetri is easily distinguished from the dromaeosaurid Buitreraptor, the only other known small theropod from La Buitrera. Phylogenetic analysis supports alvarezsauroid affinities.
The evidence supporting this relationship comes from the detailed anatomy of the ankle, however, and this concentration of character support within a single anatomical region may bias our results. If our proposed phylogenetic placement is accurate, Alnashetri antedates all
other Argentinian alvarezsaurids and indicates that alvarezsaurids were present in the Neuquén Basin throughout the entire Late Cretaceous.
Genus:Alnashetri Makovicky, Apesteguía & Gianechini, 2012
Type species: Alnashetri cerropoliciensis Makovicky, Apesteguía & Gianechini, 2012
An Argentine-Swedish research team has reported a 70-million-year-old pocket of fossilized bones and unique eggs of an enigmatic birdlike dinosaur in Patagonia.
“What makes the discovery unique are the two eggs preserved near articulated bones of its hind limb. This is the first time the eggs are found in a close proximity to skeletal remains of an alvarezsaurid dinosaur,” says Dr. Martin Kundrát, dinosaur expert from the group of Professor Per Erik Ahlberg at Uppsala University.
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