Maxakalisaurus

Skeletal reconstruction of Maxakalisaurus Topai

• Brazil ( Adamantina Formation)

• Maxakalisaurus Topai

Maxakalisaurus is a genus of sauropod dinosaur from the group of Titanosauria. So far, a single fragmentary skeleton is only known that from the late Cretaceous of Brazil. The only way is Maxakalisaurus Topai.

Features

Maxakalisaurus was all Sauropodoen as indicated by a barrel-shaped body with a long neck and tail. Comparisons with similar, better-known genera suggest a medium-sized sauropod with a length of about 13 meters. The fragile bones of the only known skeleton suggest, however, that this individual was not yet fully grown when it died.

Like some other Titanosaurier had Maxakalisaurus osteoderms ( dermal bones plates), as the discovery of a single, incomplete osteoderms near the skeleton suggests. This Osteoderm is 10.5 inches long, 8.4 inches wide, 6.2 inches thick and elliptically shaped. The top surface of this bone is strongly convex and provided with ornaments in the form of small bumps and pits. Titanosaurier osteoderms are always either individually or found at very few copies, which is why some researchers suggest that Titanosaurier generally wore only a few osteoderms. One possible function of the osteoderms as armor appears that according to researchers therefore questionable, because a small number of osteoderms would have shown no effective defense against predators.

From related genera is Maxakalisaurus can distinguish among other things by the dorsoventrally flattened anterior and middle caudal vertebrae body and a fourth metacarpal bone ( metacarpal ), which was 12 % shorter than the second metacarpal bone.

System

The phylogenetic relationships of Maxakalisaurus within the Titanosauria are unclear. The cervical vertebrae suggest that this genus derived ( modern ) than Isisaurus and Mendozasaurus. A very derived group of titanosaurs were the Saltasaurinae with which Maxakalisaurus shows a common feature ( flattened tail vertebrae ). In other features, however, Maxakalisaurus different from the Saltasaurinae. Researchers led by Alexander Kellner perform this genus, therefore, tentatively identified as the sister taxon Saltasaurinae.

Santucci and colleagues ( 2011) come to the conclusion that Maxakalisaurus is classified within the Aeolosaurini, along with Panamericansaurus, Rinconsaurus, Gondwana titanium and Aeolosaurus. This Maxakalisaurus, Rinconsaurus and Panamericansaurus were basal ( original ) members of this group, while Aeolosaurus Gondwana and titanium were derived ( advanced ) representative.

History of discovery and naming

The only known skeleton was during four digs, which carried out the National Museum of Campina Verde in the years 1998, 2000, 2001 and 2002, recovered. The site is located 45 kilometers west of the city of Prata in the Brazilian state of Minas Gerais.

The bones were found spread over an area of 40 square meters. Although most of the bone was ( not related ) found inarticulate, some neck and tail vertebrae were recovered partially related. The researchers assume that almost all the bones belonged to the same individual; prove this assumption can not be, however. However, evidence of a transport of the bones are missing by water prior to embedding, which is why suspected that the bone present in situ. Three bones of the shoulder girdle overlap with other of the discovered bones and could therefore have belonged to another Maxakalisaurus - individual. The bones show signs of weathering and are partially broken. In addition to the residual bone skeleton, which include mainly vertebrae, shoulder bones, and some leg bones with, there was the part of an upper jaw including teeth. Together with the Maxakalisaurus fossils were found scattered teeth of theropod dinosaurs and crocodile -like as well as remains of turtles. The bones were recovered from fine-to medium-grain layer of a reddish sandstone, which lies above a layer of conglomerates. These rocks give evidence that Maxakalisaurus lived in a semi-arid climate with seasonal dry and rainy seasons. These deposits are part of the Adamantina lineup, which belongs to the Bauru Group.

The genus was described in 2006 by researchers led by Alexander Kellner first time scientifically. The genus name refers to the Maxakalí, an indigenous people living in the State of Minas Gerais, where the remains of the sauropod were found in the Adamantina lineup. The Style Topai epithet is derived from the name of their deities.