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Article: A new basal chaeomysticete (Mammalia: Cetacea) from the Late Oligocene Pysht Formation of Washington, USA

Papers in Palaeontology - Volume 2 Part 4 - Cover
Publication: Papers in Palaeontology
Volume: 2
Part: 4
Publication Date: November 2016
Page(s): 533 554
Author(s): Carlos Mauricio Peredo, and Mark D. Uhen
DOI: 10.1002/spp2.1051
Addition Information

How to Cite

PEREDO, C.M., UHEN, M.D. 2016. A new basal chaeomysticete (Mammalia: Cetacea) from the Late Oligocene Pysht Formation of Washington, USA. Papers in Palaeontology, 2, 4, 533-554. DOI: 10.1002/spp2.1051

Author Information

  • Carlos Mauricio Peredo - Department of Environmental Science and Policy George Mason University Fairfax Virginia USA (Email:
  • Mark D. Uhen - Department of Atmospheric, Oceanic, and Earth Sciences George Mason University Fairfax Virginia USA (Email:

Publication History

  • Manuscript Accepted: 11 June 2016
  • Manuscript Received: 18 February 2016

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Wiley Online Library
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Modern baleen‐bearing mysticetes are descendant from archaic, toothed mysticetes known from the Late Eocene and Oligocene of the Pacific Ocean. These toothed mysticetes, such as aetiocetids and mammalodontids, dominate the Oligocene fossil record. However, larger bodied eomysticetids have recently been described from the Oligocene of the Pacific and western Atlantic. These eomysticetids lack functional teeth as adults and are thus considered to be the earliest members of Chaeomysticeti. A new fossil from the Olympic Peninsula, Washington State, including a partial skull, tympanic bullae, mandibles and postcrania, is here described as Sitsqwayk cornishorum gen. et sp. nov. S. cornishorum is a Late Oligocene mysticete lacking functional teeth and is the most phylogenetically basal chaeomysticete. Accordingly, S. cornishorum exhibits a mosaic of aetiocetid and eomysticetid characteristics. The presence of S. cornishorum in the North Pacific, and its phylogenetic position relative to the eomysticetids from the Southern Ocean, suggests a possible a North Pacific point of origin for Chaeomysticeti.

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