and Ingavat's identification of Siamosaurus, given that spinosaurid teeth, including many from Asia, have often been mistaken for those of aquatic reptiles like crocodilians, plesiosaurs, and ichthyosaurs. In view of this, the German palaeontologist Hans-Dieter Sues and colleagues in 2002 asserted that there is not enough material to confidently identify Siamosaurus as a dinosaur. In 2004, American palaeontologist Thomas Holtz and colleagues considered it a dubious name, stating that the teeth might instead belong to a contemporaneous fish such as a saurodontid or an ichthyodectid teleost. The same year, American palaeontologist David Weishampel and colleagues considered Siamosaurus an indeterminate theropod. In 2012, an analysis by American palaeontologist Matthew Carrano and colleagues agreed with the possibility of confusion with other reptiles, and regarded the genus as a possible indeterminate spinosaurid. They noted that oftentimes, isolated teeth are an unstable foundation for naming new theropod taxa, and most species based on them turn out to be invalid. This problem is especially common with spinosaurids, given that skull and skeletal fossils from the group are rare. Authors such as Buffetaut and Ingavat in 1986, and Hasegawa and colleagues in 2003, have noted that since crocodilian teeth are usually more strongly recurved than spinosaur teeth, they can be distinguished from each other. Crocodilians also lack the lateral double recurvature of Siamosauruss tooth crowns, which, based on their shape, were vertically inserted into the jaw, whereas long-snouted crocodilian teeth are usually angled outwards from the mouth. Though Siamosaurus and plesiosaur teeth are similar in overall shape, Buffetaut and Ingavat pointed out that plesiosaur teeth were significantly more recurved. Other researchers also noted that compared to plesiosaurs, Asian spinosaurid teeth also have coarser and more numerous flutes that extend almost the whole length of the crown. In 2008, Buffetaut and colleagues stated that the "S." fusuiensis teeth bear carinae on the plane of the crown's curvature, a condition not observed in plesiosaur teeth. The discovery of the Khok Kruat skeleton and of baryonychine teeth with dental flutes similar to those of Siamosaurus, were also brought up by the researchers as further evidence of Siamosauruss spinosaurid classification. Later discoveries revealed that largely straight tooth crowns with flutes and a lack or reduction of serrations were unique characteristics of spinosaurid teeth. In 2014, Italian palaeontologist Federico Fanti and colleagues considered the various spinosaurid teeth from East Asia, including those of S. suteethorni, as identical to those of Spinosaurus.