Intra- and interspecific variation in the lower jaw of Hemiauchenia

Abstract

The remains of more than fifty individuals of a species of the genus Hemiauchenia have been recovered from the Broadwater A locality (Lisco Member of the Broadwater Formation, late Blancan) of the University of Nebraska State Museum. A study of this material reveals that most characters on which species have been based represent age stages or aspects of individual variation. Three North American species-H. vera (Matthew), H. blancoensis (Meade), H. macrocephala (Cope)-are recognized. The tooth row of H. blancoensis is longer than that of H. macrocephala in all stages of wear. The mandibular diastema is longer in H. macrocephala than in H. blancoensis. The post-P/1 diastema is shorter in H. vera than in H. blancoensis.