Irritator challengeri, a spinosaurid (Dinosauria: Theropoda) from the Lower Cretaceous of Brazil

The Braincase Anatomy of the Late Cretaceous DinosaurAlioramus(Theropoda: Tyrannosauroidea)

“…The result is an extreme reduction of the basisphenoid fossa (Carr, 1999;Witmer and Ridgely, 2009). A similar morphology is seen in the oviraptorosaur Chirostenotes (Sues, 1997) and the spinosaurids Baryonyx (Charig and Milner, 1997) and Irritator (Sues et al, 2002). The basisphenoid fossa in IGM 100/ 1844 terminates dorsally deep in the floor of the parabasisphenoid as blind parasagittal pockets communicating only with each other above a thin bony septum (figs.…”

A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia

“…The nearly complete and remarkably preserved skull and substantially complete postcranium of A. altai clearly demonstrate that Alioramus was a small, gracile, heavily ornamented, longirostrine carnivore. The skull is lightly built, and the upper jaw is more than five times longer than it is deep above the antorbital fenestra, an extraordinary ratio otherwise only seen in spinosaurids (26), the small basal tyrannosauroid Xiongguanlong (27), and a few coelurosaurs (28) among theropods. Four sets of cranial horns-one on each lacrimal and postorbital and two on each jugal-are present, as well as a series of discrete rugosities on the nasal.…”

Theropod teeth from the Middle-Upper Jurassic Shishugou Formation of northwest Xinjiang, China

“…The mesial teeth are lanceolate and have a strongly twisted mesial carina and fluted lingual surface (Carrano et al 2002;Hendrickx and Mateus 2014a). In spinosaurids, the mesial and distal serrations are minute or absent, the mesial carina always reaches the cervix, the enamel texture is deeply veined (except in Irritator) and the crowns are subcircular in cross-section and sometimes fluted on one or both lingual and labial surfaces (e.g., Charig and Milner 1997;Sereno et al 1998;Sues et al 2002;Hendrickx and Mateus 2014b).…”