   #copyright

Pelycosaur

2007 Schools Wikipedia Selection. Related subjects: Dinosaurs

    iPelycosaurs

       Fossil range: Late Carboniferous - Late Permian (non-mammalian)

   Dimetrodon grandis skeleton at the National Museum of Natural History
   Dimetrodon grandis skeleton at the
   National Museum of Natural History

                             Conservation status

   Extinct (fossil)
                         Scientific classification

   Kingdom:    Animalia
   Phylum:     Chordata
   Superclass: Tetrapoda
   Class:      Synapsida
   Order:      Pelycosauria
               Cope, 1878

                                   Groups

   Caseasauria

          Eothyrididae
          Caseidae

   Eupelycosauria

          Varanopseidae
          Ophiacodontidae
          Edaphosauridae
          Sphenacodontia

                Sphenacodontidae
                Therapsida

   The pelycosaurs (from Greek pelyx meaning 'bowl' and sauros meaning
   'lizard') were smallish to large (up to 3 meters or more) primitive
   Late Paleozoic synapsid amniotes. They appeared during the Late
   Carboniferous and reached their acme in the early part of the Permian
   Period, remaining the dominant land animals for many millions of years.
   A few stragglers continued into the late Permian.

   At least two pelycosaur clades independently evolved a tall sail,
   consisting of elongated vertebral spines: the edaphosaurids and the
   sphenacodontids. In life, this would have been covered by skin, and
   possibly functioned as a thermoregulatory device or for mating display.
   Pelycosaur fossils have been found mainly in Europe and North America,
   although some small, late-surviving forms are known from Russia and
   South Africa.

   Well-known pelycosaurs include the genera Dimetrodon, Sphenacodon,
   Edaphosaurus, and Ophiacodon.

   In 1940 the group was reviewed in detail and every species known at the
   time described (and many illustrated) in an important monograph by
   Alfred Sherwood Romer and Llewellyn Price.

   Pelycosauria is a paraphyletic taxon because it excludes the
   therapsids. For that reason the term is not used in some modern books.
   Eupelycosauria is used to designate the clade that includes most
   Pelycosaurs along with the Therapsida and the Mammals. In contrast to
   "Pelycosaurs", this is monophyletic group. Caseasauria refers to a
   pelycosaur side-branch or clade that did not leave any descendents.

   The pelycosaurs appear to have been a group of reptiles that had direct
   ancestral links with the mammalia, having differentiated teeth and a
   developing hard palate.

Taxonomy and Phylogeny

     * Class Synapsida
          + ORDER PELYCOSAURIA
               o Suborder Caseasauria
                    # Family Eothyrididae
                         @ Eothyris
                    # Family Caseidae
                         @ Casea
                         @ Cotylorhynchus
                         @ Ennatosaurus
               o Suborder Eupelycosauria
                    # Family Varanopseidae
                         @ Varanosaurus
                         @ Mycterosaurus
                         @ Mesenosaurus
                         @ Varanops
                    # Family Ophiacodontidae
                         @ Archaeothyris
                         @ Ophiacodon
                    # Family Edaphosauridae
                         @ Edaphosaurus
                         @ Ianthasaurus
                    # Sphenacodontia
                         @ Haptodus
                         @ Palaeohatteria
                         @ Pantelosaurus
                         @ Cutleria
                         @ Sphenacodontoidea
                              - Family Sphenacodontidae
                                   = Ctenospondylus
                                   = Dimetrodon
                                   = Secodontosaurus
                                   = Sphenacodon
                                   = Tetraceratops
                              - ORDER THERAPSIDA

   Retrieved from " http://en.wikipedia.org/wiki/Pelycosaur"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
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