Alamosaurus

Alamosaurus Temporal range: Late Cretaceous (Maastrichtian), 70–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Restored skeletons of Alamosaurus and Tyrannosaurus at Perot Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	†Sauropodomorpha
Clade:	†Sauropoda
Clade:	†Macronaria
Clade:	†Titanosauria
Family:	†Saltasauridae
Subfamily:	†Opisthocoelicaudiinae
Genus:	†Alamosaurus Gilmore, 1922
Type species
†Alamosaurus sanjuanensis Gilmore, 1922

Alamosaurus (/ˌæləmoʊˈsɔːrəs/;^[1] meaning "Ojo Alamo lizard") is a genus of titanosaurian sauropod dinosaurs containing a single known species, Alamosaurus sanjuanensis, from the Maastrichtian age of the Late Cretaceous period in what is now southwestern North America. It is the only known titanosaur to have inhabited North America after the nearly 30-million year absence of sauropods from the North American fossil record and probably represents an immigrant from South America.

Adults would have measured around 26 metres (85 ft) long, 5 metres (16 ft) tall at the shoulder and weighed up to 30–35 tonnes (33–39 short tons), though some specimens indicate a larger body size. Isolated vertebrae and limb bones suggest that it could have reached sizes comparable to Argentinosaurus and Puertasaurus, which would make it the absolute largest dinosaur known from North America.^[2] Its fossils have been recovered from a variety of rock formations spanning the Maastrichtian age. 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.^[3]