Dravidosaurus

Dravidosaurus (meaning "Dravidanadu lizard", Dravidanadu being a region in the southern part of India where the remains were discovered) is a controversial genus of prehistoric reptile. It was first described as the last surviving stegosaurian, the group of "plated" dinosaurs. With an estimated length of three metres (10 ft), it would have also been the smallest member of the group.[1] More recent studies, however, have shown that the bones actually belonged to a plesiosaurian marine reptile, and that none of the remains are demonstrably dinosaurian in origin.[2] Dravidosaurus lived in the Late Cretaceous period (Coniacian stage) of what is now India. It is only known from disassociated remains that were originally described as comprising a partial skull, a tooth, a sacrum, an ilium, an ischium, a dermal plate, and a spike. The badly weathered remains were discovered in marine deposits near Ariyalur in the state of Tamil Nadu in South India (Trichinopoly Group). They were in 1979 named by P.M. Yadagiri and Krishnan Ayyasami as the type species Dravidosaurus blanfordi, the specific name honouring William Thomas Blanford. The holotype partial skull is catalogued as GSI SR Pal 1, while other specimens are catalogued GSI SR Pal 2-7.[3] In 1991, Sankar Chatterjee visited the site and claimed, without presenting concrete morphological evidence, that Dravidosaurus was based on plesiosaurian pelvic and hindlimb elements, the species being a nomen dubium.[4] However, this claim was rejected by Galton and Upchurch (2004), who noted that the skull, tooth and plate of Dravidosaurus are certainly not plesiosaurian as illustrated.[5] Galton and Ayyasami (2017) reaffirmed the stegosaurian classification of Dravidosaurus, claiming the remains do not look like plesiosaurian pelvic and hindlimb elements. They announced that stegosaurian remains from the Dravidosaurus type locality are under study by one of the original describers of Dravidosaurus.[6]