Alamosaurus
Alamosaurus (; meaning "Ojo Alamo lizard") is a genus of titanosaurian sauropod dinosaurs, containing a single known species, Alamosaurus sanjuanensis, from the late Cretaceous Period of what is now southern North America. Isolated vertebrae and limb bones indicate that it reached sizes comparable to "Argentinosaurus" and "Puertasaurus", which would make it the largest dinosaur known from North America. Its fossils have been recovered from a variety of rock formations spanning the Maastrichtian age of the late Cretaceous period. Specimens of a juvenile "Alamosaurus sanjuanensis" have been recovered from only a few meters below the Cretaceous-Paleogene boundary in Texas, making it among the last surviving non-avian dinosaur species.
Evolution of dinosaurs
With the exception of "Argentinosaurus" (included to fill a gap in time), these graphs show only the length of sauropods for whom near-complete fossil skeletons are known. It doesn't show other very large sauropods (see Dinosaur size#Sauropods) because these are only known from very incomplete skeletons. The ratio of skull length to body length is much higher in "Eoraptor" than in sauropods. The longest skull graphed is of "Nemegtosaurus", which is not thought be a particularly large sauropod. The skull of "Nemegtosaurus" was found near the headless skeleton of 11 metre (36 ft) long "Opisthocoelicaudia", and it has been suggested that they may be the same species, but see Nemegtosauridae.