Boletín de la Sociedad Geológica Mexicana

Volumen 69, núm. 1, 2011, p. 135 ‒ 148

New Occurrences of Fossil Homolidae from the Eastern Pacific

Torrey Nyborg1,*, Alessandro Garassino2

1 Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92354, U.S.A.
2 Natural History Museum, Palaeontology Department, Corso Venezia 55, 20121 Milano, Italy.

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Abstract

New specimens of fossil homolid crabs collected from Cretaceous and Paleogene rocks from Canada and the western United States increase the fossil record of the Homolidae De Haan, 1839. Cretalamoha n. gen., n. sp. is reported from the Campanian Pender Formation, Vancouver Island, British Columbia, Canada. A new species, Paromola roseburgensis n. sp. from the early Eocene Roseburg Formation in Oregon, U.S.A. represents the second report for the genus in the fossil record and the first one in North America, extending the spatial and temporal ranges of the genus, from the Oligocene of Argentina to the Eocene of the North Eastern Pacific. Additional material from the Oligocene of Judkins Ridge, near Eugene, Oregon, U.S.A. assigned to Palehomola gorrelli Rathbun, 1926, allows re-evaluation of the systematic position of the genus, previously ascribed to the Homolodromiidae Alcock, 1900. The definite presence of linea homolica justifies removal of Palehomolafrom this family and inclusion within the Homolidae.

Keywords: Brachyura, Homolidae, Cretaceous, Eocene, U.S.A., Vancouver Island, Canada.