|
LIST OF THE RICHARDS SPUR (FORT SILL) TETRAPOD PALEOFAUNA Stratigraphic chart of the lower Permian (partial) Content updated April 24, 2006
|
RICHARDS SPUR VARANOPIDS (VARANOPSEIDS) Synapsida-Eupelycosauria Reisz, Wilson and Scott (1997) reported the presence at Richards Spur of varanopids skeletal elements attributable to Mycterosaurus. After in 1999, Sullivan and Reisz briefly reported the presence of a second, large, varanopid, after identified as Varanops (Maddin et Al. 2006). Varanopids is a group of small-medium size basal eupelycosaus characterized by a very lizard-like general shape of the body. The teeth, except the ones of the most basal members, are flattened and recurved, in the subclade Mycterosaurinae they are also serrated. The curvature of the varanopid teeth is gradual from the base contrary to Thrausmosaurus where the curvature is very angular and it occurs in the distal third of the tooth. The cutting edges of varanopid teeth are formed by the tapering of the edges, contrary to sphenacodontid where the teeth are square, in cross section near the base, and the cutting edges are formed by anterior and posterior ridges. The centra of the vertebrae are ventrally ridged but not sharp keeled, the neural arches are narrow with shallow escavations at the base of neural spines. The adductor crest in the ventral surface of femur is not evident. 1) Richards Spur Mycterosaurus 2) Richards Spur large varanopid (Varanops?): teeth (GAAC0068) |