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Whitneyan

The Whitneyan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), set frin 32.0 to 30.0 million years ago. It falls within the Early Oligocene. The Whitneyan is preceded by the Orellan and followed by the Arikareean NALMA stages.

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The Whitneyan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), set frin 32.0 to 30.0 million years ago.1 It falls within the Early Oligocene. The Whitneyan is preceded by the Orellan and followed by the Arikareean NALMA stages.

Ecology

The Whitneyan saw a minor decline in the diversity of feeding adaptations among North American predators. The main cause of this was the disappearance of a number of nimravids and hyaenodonts that were highly specialist carnivores combined with the appearance of a number of generalist, omnivorous canids.2

References

References

  1. Hodnett, John-Paul M.; Welsh, Edward T.; Santucci, Vincent L.; Tweet, Justin S. (2022). "A Middle Eocene brontothere (Mammalia; Perissodactyla; Brontotheriidae) from Yellowstone National Park, Wyoming". FOSSIL RECORD 8. New Mexico Museum of Natural History and Science. p. 211.
  2. Van Valkenburgh, Blaire (October 1994). "Extinction and replacement among predatory mammals in the North American late Eocene and Oligocene: Tracking a paleoguild over twelve million years". Historical Biology. 8 (1–4): 129–150. doi:10.1080/10292389409380474. ISSN 0891-2963. Retrieved 29 August 2025 – via Taylor and Francis Online.