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A RE‐EVALUATION OF SPHENACODONTID SYNAPSID MATERIAL FROM THE LOWER PERMIAN FISSURE FILLS NEAR RICHARDS SPUR, OKLAHOMA
Author(s) -
EVANS DAVID C.,
MADDIN HILLARY C.,
REISZ ROBERT R.
Publication year - 2009
Publication title -
palaeontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.69
H-Index - 63
eISSN - 1475-4983
pISSN - 0031-0239
DOI - 10.1111/j.1475-4983.2008.00837.x
Subject(s) - permian , tetrapod (structure) , paleontology , geology , fauna , laurasia , faunal assemblage , vertebrate , type locality , gondwana , biology , ecology , genus , structural basin , gene , biochemistry
Early Permian terrestrial vertebrate faunal assemblages of Laurasia are dominated by large ophiacodontid, sphenacodontid, and edaphosaurid synapsids. This pattern contrasts with the fauna recovered from the Early Permian fissure fill deposits near Richards Spur, Oklahoma, where derived nontherapsid synapsids are rare. The fragmentary remains of Thrausmosaurus serratidens constitute the only published report of Sphenacodontidae from this locality. Here, we re‐evaluate T. serratidens in light of new information on the faunal assemblage of this locality. We confirm that the type material of T. serratidens cannot be assigned to Sphenacodontidae and conclude that it pertains to an indeterminate varanopid. We also describe new material, including a partial maxilla, several isolated jaw fragments with teeth, an isolated precaniniform tooth and a posterior cervical vertebra that represents unequivocal sphenacodontid remains from the Richards Spur assemblage. This material is the first definitive record of a eupelycosaurian synapsid other than a varanopid from this important locality. Faunal similarities between Richards Spur and the Bromacker Quarry, Germany, may be reflective of upland terrestrial communities during the Early Permian.