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Resolving the identity of Platylithophycus, an enigmatic fossil from the Niobrara Chalk (Upper Cretaceous, Coniacian–Campanian)

Published online by Cambridge University Press:  15 April 2018

Allison W. Bronson
Affiliation:
American Museum of Natural History, Richard Gilder Graduate School, Central Park West at 79th Street, New York, NY 10024 〈abronson@amnh.org〉
John G. Maisey
Affiliation:
American Museum of Natural History, Division of Paleontology, Central Park West at 79th Street, New York, NY 10024 〈maisey@amnh.org〉

Abstract

Misidentified fossils are common in paleontology, but Platylithophycus has undergone a particularly problematic series of descriptions. The holotype of P. cretaceus comes from the Upper Cretaceous Niobrara Chalk of Kansas, and was first described as a calcareous green alga, based on the surface texture of the specimen. Later, Platylithophycus was re-identified as a sepiid cephalopod, based partly on a comparison of microstructure between P. cretaceus and the pen of modern squids. Platylithophycus then became part of the University of Nebraska teaching collection, where, according to paleontological legend, an undergraduate student suggested that the fossil’s tessellated surface looked a lot like shark cartilage. However, that interpretation has not been formally proposed until now. This work re-describes the holotype of Platylithophycus cretaceus as part of the branchial endoskeleton of an elasmobranch, based on both gross morphology and ultrastructure, including recognizable tessellated cartilage with intertesseral pores and joints.

Type
Taxonomic Note
Copyright
Copyright © 2018, The Paleontological Society 

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