Brachytrachelopan

Skeletal reconstruction of Brachytrachelopan

• Argentina ( Cañadón Calcáreo Formation)

• Brachytrachelopan mesai

Brachytrachelopan is a genus of sauropod dinosaur from the family of Dicraeosauridae, in the late Jurassic ( Tithonian ) in what is now Patagonia (South America ) lived.

Compared with other sauropods, which were characterized by very long necks, the neck of Brachytrachelopan reached with 150 cm length only 75 % of the hull length; so that this animal had the shortest neck of all known sauropods. The only kind and type species, Brachytrachelopan mesai, was first described by a German - Argentine research group led by paleontologists Oliver Rauhut ( Bavarian State Collection for Palaeontology and Geology, Munich) in the journal Nature in June 2005. The animal is known only by a single partial skeleton.

Features and paleoecology

The Dicraeosauridae consists of three genera that are distinguished from other sauropods by relatively short necks - in addition Brachytrachelopan are the Amargasaurus from the Lower Cretaceous of Argentina and Dicraeosaurus from Tanzania (Africa). The neck of Brachytrachelopan was shorter by about 40 % than in the other two genera. Brachytrachelopan measured less than 10 meters in length, with the strongly interconnected fluidized show that there had to be an adult animal.

Rauhut et al. notice that can be seen within the Dicraeosauridae the trend towards a shorter neck, in contrast to the trend for ever longer necks with other groups such as the diplodocids. This shows that the Dicraeosauriden occupied a different ecological niche and may have been specializing in certain food sources. The vertical movement of the neck of Brachytrachelopan was very limited, so it is assumed that a feeding rate of 1 to 2 meters in this species. Rauhut et al. suspect Dicraeosauriden occupied the same ecological niche as large iguanodons. The latter were missing on the southern continents during the Late Jurassic, but were common in North America, where again lacked the Dicraeosauriden.

From the discovery of Brachytrachelopan in Patagonia and the anatomical differences of Dicraeosauriden the researchers also conclude that this group has developed in the Middle Jurassic relatively quickly, and already widespread before the complete breakup of the continental plates of Africa and South America, and was diverse.

Fund and naming

The partial skeleton (catalog number MPEF PV - 1716) was discovered by the sheep farmer Daniel Mesa on a hill, located 25 km north -northeast of Cerro Cóndor in the province of Chubut. The bones were found in a disruption of fluvialem sandstone, which belongs geologically to Cañadón Calcáreo lineup. Although the remains are very incomplete, the bones were in the anatomical network. Rauhuts team was able to recover 20 belong together vertebrae from the neck and trunk area, as well as ribs, pelvis, and parts of the femur and tibia of a hind leg. The remaining bone may have been destroyed by erosion, many years before the skeleton was discovered.

The name for the new genus and species is composed of the Greek word brachytrachelos ( for short neck ), the name of the shepherd god Pan (because the fossil was discovered by a shepherd ) and the family name of the discoverer ( Mesa ); So it means: Mesa 's short-necked shepherd God.