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Alamosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

   iAlamosaurus

                        Fossil range: Late Cretaceous

               Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Saurischia
   Suborder:   Sauropodomorpha
   Infraorder: Sauropoda
   (unranked)  Titanosauria
   Family:     Saltasauridae?
   Genus:      Alamosaurus
   Species:    A. sanjuanensis

                                Binomial name

   Alamosaurus sanjuanensis
   Gilmore, 1922

   Alamosaurus, (AL-a-mo-SAWR-us; meaning "Alamo lizard"), is a genus of
   titanosaurian sauropod dinosaur from the Late Cretaceous Period of what
   is now North America. It was a large quadrupedal herbivore, up to 53
   feet (16 metres) in length and up to 33 tons (30 metric tonnes) in
   weight. Alamosaurus, like other sauropods, had a long neck and a long
   tail, which may have ended in a 'whiplash' structure.

Naming

   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 (σαυρα), 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.

Classification

   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 as-yet-unnamed
   Brazilian "Peiropolis titanosaur" which is used in many cladistic and
   morphologic analyses of titanosaurians (Lehman and Coulson, 2002).

History of discovery

   Alamosaurus remains have been discovered throughout the southwestern
   United States. The holotype was discovered in the Lower Kirtland
   Formation of New Mexico and, since then, Alamosaurus has also been
   found in the upper part of the Kirtland, a formation which was
   deposited during the Maastrichtian stage of the Late Cretaceous Period
   and is commonly known as the "Kirtland Shale." Bones have also been
   recovered from other Maastrichtian formations, like the North Horn
   Formation of Utah and the Black Peaks, El Picacho and Javelina
   Formations of Texas. These formations start around 74 million years ago
   and last right up to the end of the Cretaceous, 65 million years ago.
   Alamosaurus may have been one of the last dinosaurs to go extinct.

   Gilmore originally described a scapula (shoulder bone) and ischium (
   pelvic bone) in 1922. In 1946, he found a more complete specimen in
   Utah, consisting of a complete tail, a right forelimb complete except
   for the tips of the toes, and both ischia. Since then, many other bits
   and pieces from Texas, New Mexico, and Utah have been referred to
   Alamosaurus, often without much description. The most completely known
   specimen is a recently-discovered juvenile skeleton from Texas, which
   allowed educated estimates of length and mass (Lehman & Coulson, 2002).

   No skull material is known, except for a few slender teeth, and no
   armor scutes have been reported, such as those found in other advanced
   titanosaurians like Saltasaurus.

   Skeletal elements of Alamosaurus are among the most common Late
   Cretaceous dinosaur fossils found in the United States Southwest and
   are now used to define the fauna of that time and place. Other
   contemporaneous dinosaurs from that part of the world include
   tyrannosaurs, smaller theropods, Nodocephalosaurus, Parasaurolophus,
   Torosaurus and Pentaceratops, among others.
   Retrieved from " http://en.wikipedia.org/wiki/Alamosaurus"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
