Skelettrekostruktion of Spinosaurus
- South America
The Spinosauridae ( " spiked lizard " ) are a group of large carnivorous dinosaurs. Found the various species in Australia, Europe, North Africa and North America. The type species, the Spinosaurus described in 1915, characterized by long spines on the back of the processes of the vertebrae are and probably had to wear a back sail; This feature owes its name to the entire family. Today, various fossils from Africa, Asia, Europe and South America are assigned to the Spinosauridae.
Serano et al. established before 1998 with the first description of Suchomimus tenerensis a phylogenetic tree of Spinosauridae, which divided them into two subfamilies Spinosaurinae and Baryonychinae. Thus Irritator and Spinosaurus be sister represent Confirms was this representation of dal Sasso et al., 2006.
Thus, make Suchomimus and Baryonyx, whose only representative Baronyx walkeri was described in England in 1986, the Barynoychinae, whereas Irritator and Spinosaurus were compared as Spinosaurinae this. Sasso et al. add the Baryonychinae also the Cristatusaurus lapparenti described in 1998 added, the. in the original representation of Sereno et al was not yet described. As the sister group of the entire Spinosauridae the Torvosauridae with the genera Torvosaurus and Eustreptospondylus be named, but which are now attributed to the Megalosauridae.
Irritator ( synonymous with Angaturama limai )
This family tree is justified primarily by features of the skull morphology, as this part of the skeleton in most species is at least partly available. The Spinosauroidea be due primarily to the formation of strong forelimbs with a sickle-shaped claw thumb. The carried on fishing for specialization extension of the snout by a parallel extension of both the maxilla as well as the premaxilla, the specific configuration of the outer nasal cavity, as well as the formation of a secondary mouth roof are very weighty apomorphies that will underpin the monophyly of Spinosauridae. In Spinosaurinae there was a reduction in the number of teeth on and Prämaxillaria Maxillaria with a concomitant increase in the tooth gaps as well as the almost straight alignment of the teeth, which were present in both Irritator and in Spinosaurus. Spinosaurus is over Irritator mainly caused by the strong increase in the spinal processes of the spine and spinal sail formed thereby - as they looked the Irritator, but is not known.
The Altispinax described only on the basis of a tooth is now regarded as a noun dubium, for Siamosaurus are no detailed systematic data are available. Is doubted Similarly, the validity of Cristatusaurus.