Turiasauria


Turiasauria is an unranked clade of basal sauropod dinosaurs known from Middle Jurassic to Early Cretaceous deposits in Europe, North America, and Africa.

Description

Turiasauria was originally erected by Royo-Torres et al. to include Turiasaurus, Galveosaurus and Losillasaurus, all of which hail from the Villar del Arzobispo Formation of Spain. Turiasuria was defined by the authors as "all Eusauropoda closer to Turiasaurus riodevensis than to Saltasaurus loricatus". Cladistic analysis of 309 characters and 33 taxa suggests that the turiasaurians lie outside the Neosauropoda and form a monophyletic group. The clade is diagnosed by the presence of vertical neural spines, posterior centroparapohyseal laminae on the dorsal vertebrae, the absence of pre- and postspinal laminae on the dorsal vertebrae, the absence of a scapular acromial crest, the presence of a prominent humeral deltopectoral crest, medial deflection of the proximal end of the humerus, and a distinct vertical ridge on the caudal side of the distal half of the ulna.

Paleobiogeography

Turiasaurs were initially considered confined to Europe, with Turiasaurus from Spain and Zby from Portugal, and the tooth taxa Cardiodon, Neosodon, and Oplosaurus were referred to the clade, but additional members were found in North America and Africa.
Remains of a very large species of turiasaur, not yet formally identified, have recently been unearthed in Charente, West France.
Indeterminate turiasaur material, consisting of a single vertebra, has been described from an unknown locality in the Early Cretaceous Wealden Group of England.

Classification

Turiasaurus demonstrates that the evolution of enormous body size was not restricted to neosauropod clades such as the Diplodocidae and Titanosauria, but developed independently at least once in a lineage of more basal sauropods, the turiasaurians.
A 2009 thesis published by José Barco proposed that neither Galveosaurus nor Losillasaurus were turiasaurians. Later, a master thesis by Francisco Gascó and Royo-Torres et al. reaffirmed the validity of Turiasauria.