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.
Antarctosaurus
Antarctosaurus (; meaning "southern lizard") is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. The type species, "Antarctosaurus wichmannianus", was described by prolific German paleontologist Friedrich von Huene in 1929, who also described a second species in 1929. Three additional species of "Antarctosaurus" have been named since then but later studies have indicated that none of these pertain to "Antarctosaurus. Antarctosaurus giganteus," the second species, is also considered dubious but it's remains represent one of the largest dinosaurs known.