Alamosaurus by Moondawg

Alamosaurus, ("meaning "Alamo lizard"), is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now North America.

Contrary to popular assertions, this dinosaur is not named after the Alamo in San Antonio, Texas, or the battle that was fought there. The holotype, or original specimen, was discovered in New Mexico and, at the time of its naming, Alamosaurus had not yet been found in Texas. Instead, the name Alamosaurus comes from Ojo Alamo, the former name for the geologic formation in which it was found (that part of the Ojo Alamo Formation has since been reassigned to Kirtland Shale) and which was, in turn, named after the nearby Ojo Alamo trading post. The term alamo itself is a Spanish word meaning "poplar" and is used for the local subspecies of cottonwood tree. The term saurus is derived from saura , Greek for "lizard" and is the most common suffix used in dinosaur names. There is one species (A. sanjuanensis), which is named after San Juan County, New Mexico, where the first remains were found. Both genus and species were named by Smithsonian paleontologist Charles W. Gilmore in 1922.

Alamosaurus is undoubtedly a derived member of Titanosauria, but relationships within that group are far from certain. One major analysis unites Alamosaurus with Opisthocoelicaudia in a subfamily Opisthocoelicaudinae of the family Saltasauridae (Wilson, 2002). A major competing analysis finds Alamosaurus as a sister taxon to Pellegrinisaurus, with both genera located just outside Saltasauridae (Upchurch et al., 2004). Other scientists have also noted particular similarities with the saltasaurid Neuquensaurus and the BrazilianTrigonosaurus (the "Peiropolis titanosaur") which is used in many cladistic and morphologic analyses of titanosaurians (Lehman and Coulson, 2002).