Rhynchippus

From Wikipedia, the free encyclopedia

Rhynchippus
Temporal range: Late Oligocene (Deseadan)
~28.4–23.03 Ma
Pyrotherium romeroi e.jpg
Rhynchippus equinus (on land) with Pyrotherium romeroi (in water)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: †Notoungulata
Family: †Notohippidae
Subfamily: †
Genus: †Rhynchippus
Ameghino 1897
Type species
Rhynchippus equinus
Species
  • R. brasiliensis Soria & Alvarenga 1989
  • R. equinus Ameghino 1897
  • R. medianus Ameghino 1901[note 1]
  • R. pumilus Ameghino 1897

Rhynchippus ("Snout Horse") is an extinct genus of notoungulate mammals from the Late Oligocene (Deseadan in the SALMA classification) of South America. The genus was first described by Florentino Ameghino in 1897 and the type species is R. equinus, with lectotype MACN A 52–31.[2] Fossils of Rhynchippus have been found in the of Argentina, the and of Bolivia, and in the of Brazil.[3]

Description[]

Palate and upper dentition of R. equinus

Rhynchippus was about 1 metre (3.3 ft) in length and weighted up to 120 kilograms (260 lb), with a deep body and three clawed toes on each foot.[4] Although its teeth were extremely similar to those of horses or rhinos, Rhynchippus was actually a relative of Toxodon, having developed teeth suitable for grazing through convergent evolution. Unlike its relatives, Rhynchippus had no large tusks; they were the same size and shape as the incisors. Enamel on the molars allowed it to chew tough food.[5] The genus shows similarities with Mendozahippus, and .[1]

In 2016, a well-preserved specimen of R. equinus was described by Martínez et al. from the in Patagonia.[6] The extraordinary preservation of the specimen allowed the researchers to appreciate the three connected spaces that constitute a heavily pneumatized middle ear; the epitympanic sinus, the tympanic cavity itself, and the ventral expansion of the tympanic cavity through the notably inflated bullae.[7]

Paleoecology[]

Rhynchippus is located in South America
Rhynchippus
Rhynchippus
Rhynchippus
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Locations of Rhynchippus fossils

Fossils of Rhynchippus have been found in various fossiliferous stratigraphic units in South America, all restricted to the Deseadan South American land mammal age. Several specimens come from the in the Golfo San Jorge Basin in southern Patagonia, with other finds from the of the in Bolivia, the from the same country, and the of the in eastern Brazil.

The Sarmiento and Salla Formations have provided a rich assemblage of many mammals and terror birds, as Physornis. The faunal assemblage of Rhynchippus fossil locations also constitutes several crocodylians, snakes (Madtsoia), helmeted bull frogs, a catfish; Taubateia paraiba, and the caiman . The Tremembé Formation is known for the preservation of several insects.

Gallery[]

  • Sketch of Rhynchippus by Frederic Brewster Loomis

Notes and references[]

Notes[]

  1. ^ R. medianus is considered a junior synonym of R. equinus by Patterson[1]

References[]

  1. ^ a b Martínez et al., 2016, p.5
  2. ^ Martínez et al., 2016, p.6
  3. ^ Rhynchippus at Fossilworks.org
  4. ^ Patterson & Pires Costa, 2012, p.83
  5. ^ Palmer et al., 1999, p.252
  6. ^ Martínez et al., 2016, p.7
  7. ^ Martínez et al., 2016, p.27

Bibliography[]

  • Martínez, Gastón; María Teresa Dozo; Javier N. Gelfo, and Hernán Marani. 2016. Cranial Morphology of the Late Oligocene Patagonian Notohippid Rhynchippus equinus Ameghino, 1897 (Mammalia, Notoungulata) with Emphases in Basicranial and Auditory Region. PLoS ONE 11. 1–29. Accessed 2019-03-02.
  • Palmer, D. et al. 1999. The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals, 252. Marshall Editions. ISBN 1-84028-152-9
  • Patterson, Bruce D., and Leonora Pires Costa. 2012. Bones, Clones, and Biomes: The History and Geography of Recent Neotropical Mammals, 1–432. University of Chicago Press. ISBN 978-0226649191


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