Notarium

The Notarium is a bone rod which is formed by a group of fused thoracic vertebrae. This structure is characteristic for different groups of birds and for some pterosaurs ( Pterosauria ).

The Notarium serves to stabilize the fuselage spine to oppose the forces occurring during flapping a rigid hull as possible. In birds, the Notarium consists of 2-6 thoracic vertebrae and is usually separated by up to four free, nichtverschmolzene thoracic vertebrae from the sacrum ( sacrum ). However, in some genera, as in some pigeons and Steißhühnern, it articulates directly with the sacrum, where free thoracic vertebrae are entirely absent. Very pronounced the Notarium is at the pterosaur Pteranodon, in which the first 8 vertebrae are fused together.

The Notarium occurs in different groups of birds, so at the Steißhühnern ( Tinamidae ), the grebes ( Podicipedidae ) Cormorants ( Phalacrocoracidae ), the ibises and spoonbills ( Threskiornithidae ), the Flamingos ( Phoenicopteridae ), the Falk -like ( Falconidae ) the gallinaceous birds ( Galliformes ), the Cranes ( Gruidae ), the Rail cranes ( Aramidae ), the trumpeter birds ( Psophiidae ), the Kagus ( Rhynochetidae ), the sunbittern ( Eurypygidae ), the stilts Coot ( Mesitornithidae ), the flight chickens ( Pteroclididae ), the pigeons ( Columbidae ), the Hoatzin ( Opisthocomus ) and the fat Schwalm ( Steatornis ).

A Notarium is also found in derived representatives of the short-tailed pterosaurs ( Pterodactyloidea ), but is absent in basal members of this group and in all basal, long-tailed pterosaurs.