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Ammosaurus

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

   iAmmosaurus

                        Fossil range: Early Jurassic

              Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Class:      Sauropsida
   Superorder: Dinosauria
   Order:      Saurischia
   Suborder:   Sauropodomorpha
   Infraorder: Prosauropoda
   Family:     Anchisauridae
   Genus:      Ammosaurus
   Species:    A. major
               Marsh, 1889

                                Binomial name

   Ammosaurus major
   Marsh, 1891

                                  Synonyms

   (originally Anchisaurus major)

   Ammosaurus (AM-o-SAWR-us; "sand lizard") is a genus of sauropodomorph
   dinosaur from the Early Jurassic Period of North America. At 4 meters
   (13 feet) in length, it was small compared to some other members of its
   suborder, which included the largest animals ever to walk the Earth. It
   was a versatile animal, able to move both bipedally and quadrupedally,
   and may have been omnivorous.

Naming

   The generic name Ammosaurus is derived from the Greek words ammos
   ("sandy ground") and sauros ("lizard"), referring to the sandstone in
   which it was found and its reptilian nature. There is one currently
   valid species (A. major), which is so named because it is larger than
   Anchisaurus, of which it was originally considered a second species.
   Famous American paleontologist Othniel Charles Marsh created this
   specific name in 1889. In 1891, Marsh created the new genus Ammosaurus
   for this species and he subsequently named another species (Ammosaurus
   solus) in 1892, although scientists now consider it synonymous with A.
   major.

Synonymy with Anchisaurus?

   The relationships of Ammosaurus with other dinosaurs are highly
   uncertain at this time. It is an early member of the suborder
   Sauropodomorpha and is most closely related to Anchisaurus, with which
   it may actually be synonymous. Different paleontologists consider
   Anchisaurus to be either a basal prosauropod (Galton & Upchurch, 2004)
   or a basal sauropod (Yates & Kitching, 2003; Yates, 2004).

   Marsh originally described Ammosaurus major as Anchisaurus major,
   although he removed it to its own new genus only 2 years later.
   However, some recent studies have suggested that Ammosaurus and
   Anchisaurus are the same animal after all (Sereno, 1999; Yates, 2004).
   Other scientists prefer to keep the two genera separate due to
   anatomical differences in the pelvis and hind foot, although the two
   animals are still considered sister taxa (Galton & Upchurch, 2004).

Fossil discoveries

   Fossils of Ammosaurus were originally discovered in the Portland
   Formation of the Newark Supergroup in the U.S. state of Connecticut.
   This formation preserves an arid environment with strong wet and dry
   seasons, from the Pliensbachian through to Toarcian stages of the Early
   Jurassic Period, roughly 190 to 176 million years ago. The original
   specimens were recovered from a sandstone quarry, which was used in the
   construction of the South Manchester Bridge in Connecticut. In fact,
   the holotype specimen was discovered by quarry workers. Unfortunately,
   it consists of only the rear half of the skeleton, as the block
   containing the front half had already been installed in the bridge. In
   1969, the bridge was demolished, and some Ammosaurus remains were
   recovered. Three other incomplete skeletons of different ages are also
   known from Connecticut, but there is no known skull (Weishampel &
   Young, 1996).

Ammosaurus outside Connecticut

   Ammosaurus remains have been reported from other parts of North
   America, but may not represent the species A. major, if they represent
   the genus at all.

   The Navajo Sandstone of Arizona is the same age as the Portland
   Formation, and has produced prosauropod remains that have been referred
   to as Ammosaurus (Galton, 1971). However, it is possible that these
   actually belong to the genus Massospondylus, otherwise known only from
   South Africa (Galton & Upchurch, 2004).

   In the Canadian province of Nova Scotia, scientists have unearthed
   prosauropods from the McCoy Brook Formation, which is about 200 to 197
   million years old, from the Early Jurassic Hettangian stage. The Nova
   Scotia material provides clues about the diet of these animals. A large
   number of gastroliths, stones swallowed to grind up plant material in
   the gut, were found in the abdomen, as well as bone from the skull of a
   small lizard, Clevosaurus. This indicates that these dinosaurs were
   omnivorous, with a diet mainly consisting of plants but with an
   occasional supplement of meat (Shubin et al., 1994). However, these
   remains have never been fully described or illustrated and are only
   tentatively referred to Ammosaurus. Further study may either confirm or
   falsify this hypothesis.
   Retrieved from " http://en.wikipedia.org/wiki/Ammosaurus"
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