Amargatitanis

• Argentina, Neuquén (La Amarga Formation)

• Amargatitanis macni

Amargatitanis is a genus of sauropod dinosaur from the group of Titanosauria that lived during the Early Cretaceous in South America. The fragmentary remains date from the Barremian of the La Amarga Formation in the Argentine province of Neuquén. Amargatitanis was a derived ( advanced ) Representatives of Titanosauria, as they are known mainly from the Upper Cretaceous. This genus shows that such derived Titanosauria already existed in the Lower Cretaceous. The only species of this genus is Amargatitanis macni.

Features

Amargatitanis used to distinguish features of the shoulder region and the hind leg of the other genera. For example, the shoulder blade was flat and wide, the edges of the central shaft were straight. The fourth trochanter of the femur (one serving as muscle attachment point spinous process ) was located at mid-height of the bone. While the head of the femur is very strong, the distal (lower ) end is weak.

Fund, Research History and naming

The only known fossils were recovered in 1983 by an excavation team under the direction of José Bonaparte. The site is located east of the city of Las Coloradas in the Argentine province of Neuquen. Probably the locality of La Amarga Formation is attributed, which came to be deposited in the Barremian; although Fund notes by José Bonaparte indicate that the locality of the much older Pichi - Picún formation is attributable to that already was deposited in the Upper Jurassic Kimmeridgian in. Other known sauropods of the La Amarga Formation include basal ( original ) Titanosauria and Diplodocoidea from groups Rebbachisauroidea and Dicraeosauridae and a basal representative of a Diplodocoidea with.

The so far only Fund ( holotype, specimen numbers MACN PV N51, 53, 34) includes six caudal vertebrae, a shoulder blade, a femur and a talus ( astragalus ) with a. The first description of the new genus and species Amargatitanis macni was published by Sebastian Apesteguia 2007. The name refers to one of the reference and the other on the Titans of Greek mythology, as an indication of the affiliation of the genus to the Titanosauria. The second part of the species name, macni is named after the Museo Argentino de Ciencias Naturales ( MACN ), which has made ​​significant contributions to the study of fossil vertebrates during the 19th and 20th centuries.