Neosodon (meaning "new tooth") was a genus of sauropod dinosaur from the Late Tithonian-age Upper Jurassic Sables et Gres a Trigonia gibbosa of Départment du Pas-de-Calais, France.[1][2] It has never been formally given a species name, but is often seen as N. praecursor, which actually comes from a different animal. Often in the past, it had been assigned to the wastebasket taxon Pelorosaurus, but restudy has suggested that it could be related to Turiasaurus, a roughly contemporaneous giant Spanish sauropod. It is only known from six teeth.[3]
Moussaye named this genus for a large, broken, worn tooth found in Wilmille, near Boulogne-sur-Mer, and neglected to give it a species name. He thought that it belonged to a theropod like Megalosaurus.[3] Since then, five more teeth have been found and assigned to Neosodon.
Sauvage synonymized it with his tooth species Iguanodon praecursor,[4][5] which by this time had become mixed up with Edward Drinker Cope's roughly contemporaneous American Morrison Formation genus Caulodon (now a synonym of Camarasaurus). However, the two are not based on the same type, as "I". praecursor comes from slightly older rocks: the same unnamed Kimmeridgian formation as Morinosaurus.[6] Earlier reviews (Romer, 1956; Steel, 1970) accepted it as a synonym of Pelorosaurus, and considered it a possible brachiosaurid.[7][8]
In the 1990s, French researchers published on new camarasaurid bones from the same formation. At first, Buffetaut and Martin (1993) suggested that they belonged to Neosodon praecursor,[9] but Le Loeuff et al. (1996) later rejected this, as Neosodon is based only on several teeth, which did not overlap the new material.[10] The latest review accepted both Neosodon and "Iguanodon" praecursor as dubious sauropods.[11] However, Royo-Torres et al. (2006), in their description of Turiasaurus, noted that this tooth was similar to those of their genus and suggested that it could be a turiasaur.[12]
The teeth referred to Neosodon are large (60 mm [2.36 in] tall and a cross-section of 35 by 20 mm (1.38 by 0.79 in) in its incomplete state, estimated at 80 mm [3.15 in] tall if complete)[3] and spear-like or spatulate in shape. The owner would have been a large, quadrupedal herbivore.[11]