7-1 ‘Larry the Lobster’, A New Fossil Lobster Species of Nephropsis (Decapoda, Homarida, Nephropidae)

Session: Undergraduate Research, Part I (Posters)

Presenting Author:

Authors:

Abstract:

The Upper Eocene (34-34.5 Ma) to the Lower Miocene (23 Ma) Lincoln Creek Formation in Washington, USA, was deposited in a continental shelf environment, rife with volcanic activity and resulting in the tuffaceous siltstones and sandstones that now comprise much of the formation (Beikman et al, 1967; Prothero et al, 2008). During this time, it was home to many invertebrate taxa, including multiple genera of decapods. The fossil record of decapods in the Pacific Northwest of the United States is dominated by crabs, with only three fossil lobster species from the Pacific Northwest, all three from the genus Hoploparia, being documented. The Lincoln Creek Formation contains roughly thirteen genera of fossil decapods, six of which are extinct. Pulalius and Callianassa sensu lato make up the majority of the fossil decapods in the formation. The discovery of a different genus of fossil lobster might be expected as we learn more about the paleoecology of the region. However, the presence of a fossil lobster of the genus Nephropsis is not only rare in the fossil record, but in this specific locality, too. Nephropsis is known from eighteen extant species and only one fossil species. The fossil species, Nephropsis midwayensis (Rathbun, 1935) is from the Lower Eocene (56-48 Ma) of Wilcox County, Alabama. Additionally, nearly every other species of Nephropsis is known from either the Atlantic Ocean or the Indo-West Pacific Ocean, with only one being native to the Western Pacific coast of Central America. Thus, the discovery of not only a fossil species, but one in the Northeastern Pacific Ocean, forms the basis of this work and description of a new species of Nephropsis.  

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