A Pliocene fauna from Western Nebraska / by W.D. Matthew and Harold J. Cook.

  • Matthew, William Diller, 1871-1930.
Date:
1909
Catalogue details

Licence: In copyright

Credit: A Pliocene fauna from Western Nebraska / by W.D. Matthew and Harold J. Cook. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    1909.] of the premolars is carried further than in any of the described forms, M. swims Leidy being nearest in this respect. The genus Ilyamognathus Merriam, from the Pleistocene of California, carries this specialization still further, but it is not certain that it can be derived from JEltirodon. In the Snake Creek species the lower^teeth correspond in all details to /hlurodon, and three unassociated upper earnassials have the parastyle well developed. JElurodon haydeni validus mut. nov. This mutation differs from the type of .E. haydeni Leidy, in the shorter and more crowded premolar region, reduction of the tubercular teeth, and slight enlargement of the carnassial. It is based upon a lower jaw, No. 14147, with p4-m2 complete, and roots or alveoli of the other teeth. P4 shows the characteristic form of JElurodon, in its massive proportions, peculiar backward pitch of the protoconid, broad cingulate heel, and high Fig. 2. JElurodon haydeni validus, lower jaw, type specimen, external view X i, and crown view of teeth natural size. strong posterior accessory cusp. P3 is much smaller, and set somewhat transversely in the jaw; in front of it is another transversely set tooth and the presence or absence of px cannot be demonstrated. The canine alveolus indicates a large and massive tooth. M, is like that of the other dSlurodons, with massive paraconid and protoconid, small, low metaconid, and rather small bicuspid heel. It is longer but less robust than in Ilyamognathus