New Decapoda (Anomura, Brachyura) from the Eocene Bateque and Tepetate Formations, Baja California Sur, México

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Bulletin of the Mizunami Fossil Museum

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Decapoda, Brachyura, Anomura, Eocene, Bateque Formation, Baja California, Mexico


Earth Sciences | Geology | Paleontology


Unusually preserved decapod specimens from the Eocene Bateque Formation of Baja California Sur, México, have heretofore been undescribed. This robust fauna has yielded thirteen taxa with seven new species, including Homola bajaensis, Raninoides acanthocolus, R. proracanthus, Prehepatus mexicanus, Daldorfia salina, Anatolikos undecimspinosus, and Paracorallicarcinus tricarinatus. In addition, several taxa are identifiable to the family level. Laeviranina is synonymized with Raninoides, resulting in numerous new combinations. The Bateque Formation fauna has yielded the oldest known occurrence of Anatolikos, Homola, Daldorfia, and the Daldorfiidae as well as the first notice of Prehepatus in the Eocene and the first articles of the cheliped of Prehepatus other than those of the chelae. Micropaleontological interpretation of the sediments collected at Pelican Island suggests that the Bateque Formation at that location was deposited in an oligotrophic, outer shelf or platformal setting, in water of at least 30 m depth. The decapods of the Bateque Formation exhibit Tethyan and North Pacific distributional patterns and are a mixture of warm and cool, shallow, epicontinental, and deep water taxa. These patterns are interpreted to be a result of Baja California's Eocene position in the crossroads of the North Pacific and Tethyan distributional pathways.