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Open Access Publications from the University of California
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Cover Caption: Partial left mandible (KUVP 48020) of an antilocaprid from Wyoming, in left labial (top) and occlusal views.

Articles

Pleistocene lagomorphs from Cathedral Cave, Nevada

Faunal data from Cathedral Cave, Nevada, provide insight into biotic changes that occurred within the Great Basin prior to the latest Pleistocene. Taxonomic identifications of lagomorphs from Cathedral Cave were made using a morphological approach intended to minimize geographic and temporal assumptions. Although this approach to identification is conservative, the resultant data set is appropriate for inclusion in future analyses of regional biotic change. Lagomorphs recovered from the site include new regional records of two extinct taxa, Aztlanolagus agilis and Brachylagus coloradoensis. Other lagomorphs from Cathedral Cave include Brachylagus idahoensis, Ochotona sp., and Sylvilagus or Lepus sp. The presence of a posterorinternal reentrant fold on the p3 of some specimens of Ochotona sp. suggests that the range of variation present in the individual teeth of pikas needs to be described in further detail. In contrast to a previously established hypothesis of increasing enamel complexity in the p4 of Aztlanolagus agilis, evaluation of crenulation patterns of Aztlanolagus agilis from Cathedral Cave showed no distinct trends.

A new immigrant mustelid (Carnivora, Mammalia) from the middle Miocene Temblor Formation of central California

A new mustelid genus from the Barstovian (middle Miocene) marine Temblor Formation in California is described. The material of Legionarictis fortidens includes an incomplete cranium with partial upper dentition. The straight lingual border and slightly expanded posterointernal cingulum of M1 are plesiomorphic traits, as in the European Dehmictis. However, the M1 is not as posteriorly expanded, and the P4 does not have a lingual hypoconal crest, differentiating L. fortidens from younger North American forms. Furthermore, the P4 protocone is posteriorly placed from the parastyle crest, as in the extant South American Eira. An autapomorphic feature of L. fortidens is its highly hypertrophied P4 paracone with a bulbous crown. The robust upper carnassial, very strong development of the sagittal crest, and derived enamel microstructure all suggest a hard food component in its diet. The coastal depositional environment indicated by the presence of marine taxa in the Temblor Formation suggests that hard shelled invertebrates might have been a food source of L. fortidens. A combination of plesiomorphic and derived dental characteristics puts the new form at an evolutionary stage basal to otters and closer to the living Eira. Cladistic analysis of craniodental characters suggests that L. fortidens is more derived than generalized basal mustelines of the Old World, and may have diverged from the lutrine lineage in a separate immigration event to the New World.

New record of an extinct fish, Fisherichthys folmeri Weems (Osteichthyes), from the lower Eocene of Berkeley County, South Carolina, USA

Fisherichthys folmeri Weems 1999 (Sciaenidae?) is an extinct teleostean fish occurring in marine strata of the Gulf and Atlantic coastal plains, USA. We report isolated teeth collected from a lower Eocene (Ypresian) deposit in Berkeley County, South Carolina. Crowns of unworn teeth bear apical papillae surrounding a central depression, but these features are lost as teeth are worn through in vivo usage. The pulp cavity appears to become reduced in size as the tooth matures in the alveolus. Fisherichthys folmeri is thus far only known from Mississippi, South Carolina, and Virginia in strata ranging in age from 50.8 to 55 Ma.

The earliest North American record of the Antilocapridae (Artiodactyla, Mammalia)

The Family Antilocapridae is considered to have first appeared in the Early Hemingfordian of western North America. Here we report a mandible of a merycodontine antilocaprid from the Late Arikareean Harrison Formation of eastern Wyoming. The mandible has three lower molars preserved and mandibular ramus features that allow it to be differentiated from other contemporaneous selenodont artiodactyl families, yet the lack of detailed understanding of intraspecific variation in Paracosoryx and Merycodus warrant caution in assigning this to a genus. This new material predates the previous first appearance of antilocaprids by approximately 3–4 million years and suggests that antilocaprid immigration from Eurasian ruminant stock occurred earlier than previously assumed and that caution should be exercised when using first appearances in broader analyses.