A Basal Elasmobranch, Thrinacoselache gracia n. gen & sp., (Thrinacodontidae, New Family) from the Bear Gulch Limestone, Serpukhovian of Montana, USA

  title={A Basal Elasmobranch, Thrinacoselache gracia n. gen \& sp., (Thrinacodontidae, New Family) from the Bear Gulch Limestone, Serpukhovian of Montana, USA},
  author={Eileen D. Grogan and Richard Lund},
Abstract A new elasmobranch, Thrinacoselache gracia, is described from the Bear Gulch Limestone lens (Heath Formation; Sepukhovian) of Montana, with an elongate neurocranial region, occipital region that incorporates several separate vertebral zygal elements, extremely elongate, low body, and anatomically heterocercal, but horizontally oriented tail. Teeth are borne upon the rostrum, palatoquadrate, and mandible. The palatoquadrates articulate with both palatobasal and postorbital processes, as… 

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