Dicraeosaurus

Dicraeosaurus
Temporal range: Late Jurassic, 155–150 Ma
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Dicraeosaurus skeleton
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Clade:Dinosauria
Order:Saurischia
Suborder:†Sauropodomorpha
Clade:†Sauropoda
Family:†Dicraeosauridae
Subfamily:†Dicraeosaurinae
Janensch, 1929
Genus:†Dicraeosaurus
Type species
†Dicraeosaurus hansemanni
Species
  • D. hansemanni Janensch, 1914
  • D. sattleri Janensch, 1914

Dicraeosaurus (Gr. δικραιος, dikraios "bifurcated, double-headed" + Gr. σαυρος, sauros "lizard") is a genus of small diplodocoid sauropod dinosaur. It was named for the spines on the back of the neck. The first fossil was described by paleontologist Werner Janensch in 1914.

Description

Restoration of D. hansemanni

Unlike most diplodocoids, Dicraeosaurus had a large head with a relatively short and wide neck. The neck contained 12 unusually short vertebrae, so it could probably browse vegetation only from ground level to a height of about 3 metres (9.8 ft).[1] It also lacked the whiplash tail that other diplodocids had. It was smaller, at only reached 12 metres (39 ft) in length. It gets its name, which means two-forked lizard, from the spines that came from the vertebrae. They were not straight as in some members of the family. Each one was “Y” shaped, like a fork. These spines also provided muscle attachment points.[2]

Classification

Dicreosaurids shown to scale

The following cladogram follows an analysis by Sereno et al. in 2007.[3]

Diplodocoidea

 

Diplodocidae

 

Apatosaurus

 
 

Diplodocus

 
 
 

Suuwassea

 
Dicraeosauridae

 

Amargasaurus

 
 

 

Brachytrachelopan

 
 

Dicraeosaurus

 
 
 
 
Rebbachisauridae

 

Histriasaurus

 
 

 

Rebbachisaurus

 
 

 

 

 

Cathartesaura

 
 

Limaysaurus

 
 
 

Zapalasaurus

 
 
 

 

Demandasaurus

 
 

Nigersaurus

 
 
 
 
 
 

Palaeoecology

Restoration of the head

Dicraeosaurus lived in the Late Jurassic. It was herbivorous; however, it didn’t compete with other dinosaurs for vegetation. Fossils have been discovered in the rocks of Tendaguru Hill in Tanzania. The rocks also yield fossils of Giraffatitan and Kentrosaurus. As there was a distinct difference in size between these animals, they would probably have browsed for vegetation at different levels, allowing them to co-exist without significant competition.[2]

References

  1. ↑ Benton, Michael J. (2012). Prehistoric Life. Edinburgh, Scotland: Dorling Kindersley. p. 270. ISBN 978-0-7566-9910-9.
  2. 1 2 Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 132. ISBN 1-84028-152-9.
  3. ↑ Sereno PC, Wilson JA, Witmer LM, Whitlock JA, Maga A, et al. (2007) Structural Extremes in a Cretaceous Dinosaur. PLoS ONE 2(11): e1230.
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