Lurdusaurus ("heavy lizard") is a genus of massive and unusually shaped iguanodont dinosaur from the Elrhaz Formation in Niger. It contains one species, L. arenatus. The formation dates to the Early Cretaceous, roughly 112 million years ago. Lurdusaurus has a highly atypical body plan for an iguanodont, with a small skull, long neck, rotund torso, and powerful forelimbs and claws, somewhat reminiscent of a ground sloth. Its metacarpals (wrist bones) are fused and reinforced into a large block, and the thumb spike is remarkably enormous. These would have allowed the hand to have functioned almost like a ball-and-chain flail. Lurdusaurus is estimated to have been long and high when on all-fours, but its stomach would have been only off the ground. It may have weighed , conspicuously heavy for an iguanodontid this size. Paleontologist Thomas R. Holtz Jr. speculated Lurdusaurus may have behaved much like a hippo. It lived in a forested, riverine environment alongside the iguanodonts Elrhazosaurus and Ouranosaurus, the sauropod Nigersaurus, an undescribed titanosaurid, the spinosaurid Suchomimus, the carcharodontosaurid Eocarcharia, the abelisaurid Kryptops, and an undescribed noasaurid. The site also yielded several crocodylomorph species and a pterosaur. Discovery In 1965, Philippe Taquet discovered the holotype specimen at the Gadoufaoua site of the Elrhaz Formation, in the Tenere desert of Niger. It consists of a nearly complete adult iguanodont skeleton with a fragmentary skull belonging to single individual, which was given the catalogue number MNHN GDF 1700. He noted it had rather massive proportions, and in 1976 noted it should probably be classified into a new genus while briefly describing the material. Paleontologist Souad Chabli described the remains in 1988 for her PhD thesis, under the direction of Taquet. She named it "Gravisaurus tenerensis". However, her dissertation was never published. In 1999, Turquet and American paleontologist Dale Russell published the first formal description, naming it Lurdusaurus arenatus. The generic name comes from Latin lurdus "heavy" and Ancient Greek sauros "lizard", in reference to the enormous weight of the fossils. The specific name arenatus is Latin for "sandy" because it was found in a desert. They also referred a dentary fragment, MNHN GDF 43G, and a right coracoid, GDF 381, to the species. Description The tip of the snout may have been about wide, and expanded back to . That is, like other iguanodonts, it did not have a duck-like bill. No teeth were preserved, but MNHN GDF 43G preserves