Lotosaurus is a paracrocodylomorph from middle Triassic China. It was between 4.9 and 8.2 ft in length and herbivorous.
Description[]
Lotosaurus was 1.5 to 2.5 m (4.9 to 8.2 ft) long and a heavily built quadruped. It was a herbivore, shearing off leaves with its toothless, beaked jaws. Lotosaurus, like some other members of the Poposauroidea, had a sail on its back, granting it an appearance superficially similar to that of Permian pelycosaurs like Dimetrodon and Edaphosaurus, although not as high.
Classification[]
Lotosaurus was originally thought to be a thecodont, probably related to Ctenosauriscus and other archosaur taxa with elongated neural spines (=Ctenosauriscidae). Although modern cladistic analyses have abandoned the order Thecodontia, they have also supported the theory that Lotosaurus was a distant relative of ctenosauriscids. Nesbitt (2007) was the first to suggest that Lotosaurus is more closely related to Shuvosaurus (a shuvosaurid) than to Arizonasaurus (a ctenosauriscid). In his massive revision of archosaurs which included a large cladistic analysis, Sterling J. Nesbitt 2011 found Lotosaurus to be a member of the group Poposauroidea. Poposauroids were part of Pseudosuchia, the lineage of reptiles which also includes aetosaurs, raisuchids, and modern crocodilians.
Within Poposauroidea, Lotosaurus was placed as a relative of the Shuvosauridae, and therefore it is not included in the Ctenosauriscidae. Although shuvosaurids walked on two legs and lacked sails, their toothless beaks and presumed herbivorous habits resembled those of Lotosaurus. Ctenosauriscids were carnivores with many sharp teeth and high, theropod-like skulls, in contrast to Lotosaurus and shuvosaurids. Nevertheless, Lotosaurus is still considered a distant relative of ctenosauriscids, as that family is also placed within Poposauroidea. Further studies confirmed these results.