Campylodoniscus ameghinoi (gr. "curved tooth") is the only known species of the dubious extinct genus Campylodoniscus , possibly titanosaurian sauropod dinosaur, which lived at the end of the Cretaceous period, approximately 83 to 65 million years ago, between the Campanian and the Maastrichtian, in what today is Argentina. The age of Campylodoniscus is in doubt, it could be from the Cenomanian, about 95 million years ago, or the Campanian-Maastrichtian, about 70 million years ago. It is sometimes estimated to be around 20 meters in length. Campylodoniscus is probably a member of Titanosauria. Some researchers consider it a nomen dubium.
The type species, C. ameghinoi was described by Friedrich von Huene in 1929 who called it Campylodon , which was pre-occupied, being changed by Haubold and Kuhn in 1961 to the current name. The genus name meaning 'bent tooth' ', from the Greek καμπυλος, 'bent' or 'curved' (like a bow) and ὀδών meaning 'tooth'. The specific name honors Florentino Ameghino. In 1961, Oskar Kuhn noticed that the name was occupied by a fish and renamed the genus Campylodoniscus, the diminutive.
It is represented by the holotype MACN A-IOR63 , an incomplete maxilla with teeth with spatulate crowns wider than those of diplodocids, but not as wide as those of camarasaurids and absolutely different from the thin and tiny peg-shaped teeth of Antarctosaurus. and Alamosaurus , having a form intermediate between all of these. A second jaw described by Huene and Matley in 1933 from the late Cretaceous was found in India, the teeth are missing, however the fossil is tall and robust, as in camarasaurids. Due to the incomplete state of the two jaws, they cannot be compared critically and in no way can they be said to be related. It has been proposed that it is a basal titanosaur that survived until the end of the Cretaceous.