70-3 FOSSIL CAMELS FROM THE MIOCENE PUNCHBOWL, CROWDER, AND CAJON VALLEY FORMATIONS OF THE TRANSVERSE RANGES, CALIFORNIA

Session: Paleontology, Biogeography/Biostratigraphy & Phylogenetic/Morphological Patterns (Posters)

Presenting Author:

Authors:

Abstract:

Fossil camels from the middle-late Miocene units of the Transverse Ranges have never been precisely identified beyond “Camelidae” in the literature, because the taxonomy of Miocene camels was so outdated and poorly understood. With the revision of North American Camelidae now completed, it is possible to identify them for the first time. The type Punchbowl Formation in Devil’s Punchbowl State Park has produced Clarendonian mammals like Borophagus, Plioceros, and Pliohippus. Its fragmentary camel jaws and teeth closely match the size and hypsodonty of Barstovian-Clarendonian Procamelus occidentalis. The Cajon Valley Formation west of the Cajon Pass (long misidentified as the “Punchbowl Formation”) has produced a diverse fauna that ranges from the late Hemingfordian to the early Barstovian. The camels recovered from this unit include a skull and jaws of Protolabis saxeus (typical of the late Hemingfordian) and a skull of Miolabis fricki (previously only known from the late Hemingfordian of the Cuyama Badlands of Ventura County, California). In addition, it produces limb bones and teeth and jaws of a giraffe-like aepycameline, probably Honeycamelus priscus of the late Hemingfordian or Aepycamelus giraffinus of the Barstovian. The Crowder Formation along Highway 138 east of the Cajon Pass is thought to be late Hemingfordian based on fossil rodents. It produces fragmentary jaws of a small camelid that best matches the late Hemingfordian taxon Paramiolabis tenuis. It is striking that the late Hemingfordian Crowder and Cajon Valley formations, which are the same age and only a few kilometers from each other, produce such different assemblages of camels, although the Crowder specimens tend to be more broken and difficult to identify than those of the Cajon Valley Formation. Nevertheless, many of the camels found in the Cajon Valley and Crowder formations are similar to those of the Barstow Formation and Cuyama Formation, as well as taxa best known from the High Plains.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6472

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