Bathyopsis

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title: "Bathyopsis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["dinoceratans", "extinct-mammals-of-north-america", "fossil-taxa-described-in-1881", "prehistoric-placental-genera", "taxa-named-by-edward-drinker-cope"] description: "Extinct North American mammal" topic_path: "general/dinoceratans" source: "https://en.wikipedia.org/wiki/Bathyopsis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct North American mammal ::

| fossil_range = | image = Bathyopsis.jpg | image_caption = Bathyopsis fissidens skull | taxon = Bathyopsis | authority = Cope, 1881 | type_species = †Bathyopsis fissidens | subdivision_ranks = Species | subdivision = *†B. fissidens (Cope, 1881)

• †B. middleswarti (Wheeler, 1961)

Bathyopsis, from Ancient Greek βαθύς (bathús), meaning "thick", and ὄψις (ópsis), meaning "face", is an extinct genus of dinocerates. The genus is known from Eocene North America.

Description

Bathyopsis is intermediate, morphologically, from the basal Prodinoceras and Probathyopsis (part of the family Prodinoceratidae) and the later dinocerate genera Tetheopsis and Eobasileus. Bathyopsis possesses small cranial horns, one pair being on the maxilla, another pair on the frontal, and a pair on the parietal. The genus lacks any upper incisors, but has greatly enlarged canines. Molar-wise, Bathyopsis is similar to Uintatherium in morphology, and the molars are less elongate than those in Probathyopsis. The mandible bears a large flange, much like other uintatheriines. The skull has been described as dolichocephalic. The limb structure is graviportal and digitigrade, indicating an increase in size compared to earlier dinocerates.{{cite book | isbn = 9780486838557 | url = https://books.google.com/books?id=QCC9DwAAQBAJ&dq=Eobasileus+weight&pg=PA555 | title = The Fossil Book: A Record of Prehistoric Life | publisher = Dover Publications | date = January 15, 2020 | access-date = 4 September 2022 | pages = 555 | author = Patricia Vickers Rich, Thomas Hewitt Rich, Mildred Adams Fenton, Carroll Lane Fenton ::figure[src="https://upload.wikimedia.org/wikipedia/commons/9/97/Bathyopsis_fissidens.JPG" caption="''Bathyopsis fissidens''"] ::

Classification

Historically, Bathyopsis had also been assigned to the Pantodonta, though this is not supported. Bathyopsis is considered a sister group to the other uintatheriines on the basis that it bears much smaller cranial horns and is generally smaller than the other uintatheriines. In the past, Bathyopsis had been ascribed to both a separate family (Bathyopsidae), by Henry Fairfield Osborn, and a subfamily of its own, (Bathyopsinae), by Wheeler in 1961. This decision, however, was reversed by Schoch and Lucas in 1985, who established the (now disused) tribe Bathyopsini. There is an indeterminate species of Bathyopsis known from a singular premolar, which resembles Probathyopsis in shape.

Phylogeny in accordance with Scott et al. (1998):

References

References

1. "Mindat.org".
2. Janis, Christine M.. (1998-05-28). "Evolution of Tertiary Mammals of North America: Volume 1, Terrestrial Carnivores, Ungulates, and Ungulate Like Mammals". Cambridge University Press.
3. "Osborn, Henry Fairfield, - Biodiversity Heritage Library".
4. Cope, E. D.. (1885). "The Amblypoda (Continued)". The American Naturalist.
5. Wheeler, Walter. (1961-01-01). "Revision of the uintatheres". Bulletin of the Peabody Museum of Natural History.
6. Wood, Horace Elmer. "The problem of the Uintatherium molars. Bulletin of the AMNH ; v. 48, article 18".
7. Simpson, George Gaylord. "A new Paleocene uintathere and molar evolution in the Amblypoda. American Museum novitates ; no. 387".
8. Hay, Oliver Perry. (1902). "Bibliography and catalogue of the fossil vertebrata of North America". Govt. Print. Off.
9. Lucas, Spencer G.. (2001-02-01). "Gobiatherium (Mammalia: Dinocerata) from the Middle Eocene of Asia: Taxonomy and biochronological significance". Paläontologische Zeitschrift.

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