Rhynchippus
{{Short description|Extinct genus of notoungulates}}
{{Automatic Taxobox
| image = Rhynchippus equinus - upper palate and dentition - Sarmiento Formation, Argentina.jpg
| image_caption = Palate and upper dentition of R. equinus
| fossil_range = Late Oligocene (Deseadan)
~{{fossil range|28.4|23.03}}
| taxon = Rhynchippus
| authority = Ameghino 1897
| subdivision_ranks = Species
| subdivision =
- R. brasiliensis {{small|Soria & Alvarenga 1989}}
- R. equinus {{small|Ameghino 1897}}
- R. medianus {{small|Ameghino 1901{{refn|group=note|R. medianus is considered a junior synonym of R. equinus by PattersonMartínez et al., 2016, p.5}}}}
- R. pumilus {{small|Ameghino 1897}}
| type_species = †Rhynchippus equinus
| type_species_authority = Ameghino 1897
}}
Rhynchippus ("beaked 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.{{Cite journal |last1=Martínez |first1=Gastón |last2=Dozo |first2=María Teresa |last3=Gelfo |first3=Javier N. |last4=Marani |first4=Hernán |date=2016-05-27 |title=Cranial Morphology of the Late Oligocene Patagonian Notohippid Rhynchippus equinus Ameghino, 1897 (Mammalia, Notoungulata) with Emphases in Basicranial and Auditory Region |journal=PLOS ONE |language=en |volume=11 |issue=5 |pages=e0156558 |doi=10.1371/journal.pone.0156558 |issn=1932-6203 |pmc=4883762 |pmid=27232883|bibcode=2016PLoSO..1156558M |doi-access=free}} Fossils of Rhynchippus have been found in the Agua de la Piedra and Sarmiento Formations of Argentina,{{Cite journal |last1=Hernández Del Pino |first1=Santiago |last2=Seoane |first2=Federico |last3=Cerdeño |first3=Esperanza |date=2017 |title=New postcranial remains of large toxodontian notoungulates from the late Oligocene of Mendoza, Argentina and their systematic implications |journal=Acta Palaeontologica Polonica |language=en |volume=62 |doi=10.4202/app.00301.2016 |issn=0567-7920|doi-access=free|hdl=11336/63620 |hdl-access=free }} the Salla and Petaca Formations of Bolivia, the Tremembé Formation of Brazil,[https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=43388 Rhynchippus] at Fossilworks.org and the Moquegua Formation of Peru.{{Cite journal |last1=Shockey |first1=Bruce J. |last2=Salas |first2=Rodolfo |last3=Quispe |first3=Rossana |last4=Flores |first4=Alexander |last5=Sargis |first5=Eric J. |last6=Acosta |first6=Jorge |last7=Pino |first7=Adan |last8=Jarica |first8=Nestor J. |last9=Urbina |first9=Mario |date=2006-03-30 |title=Discovery of Deseadan fossils in the upper Moquegua Formation (late Oligocene—?early Miocene) of southern Peru |url=https://www.researchgate.net/publication/232672737|journal=Journal of Vertebrate Paleontology |volume=26 |issue=1 |pages=205–208 |doi=10.1671/0272-4634(2006)26[205:DODFIT]2.0.CO;2 |s2cid=85593383 |issn=0272-4634}}{{Cite journal |last1=Shockey |first1=Bruce J. |last2=Gismondi |first2=Rodolfo Salas |last3=Gans |first3=Phillip |last4=Jeong |first4=Annie |last5=Flynn |first5=John J. |date=2009 |title=Paleontology and Geochronology of the Deseadan (late Oligocene) of Moquegua, Perú |journal=American Museum Novitates |issue=3668 |pages=1–24 |doi=10.1206/662.1 |issn=0003-0082|doi-access=free}}
Description
Rhynchippus was about {{convert|1|m|ft}} in length and weighed up to {{convert|120|kg|lb}}, with a deep body and three clawed toes on each foot.Patterson & Pires Costa, 2012, p.83 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.Palmer et al., 1999, p.252 The genus shows similarities with Mendozahippus, Eurygenium and Pascualihippus.
In 2016, a well-preserved specimen of R. equinus was described by Martínez et al. from the Sarmiento Formation in central Patagonia. 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.
Paleoecology
{{Location map+ | South America
| relief = 1
| width = 200
| float = right
| caption = Locations of Rhynchippus fossils
| places =
{{Location map~ | South America
| lat_deg = -17.2
| lon_deg = -71.0
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Moquegua Formation
}}
{{Location map~ | South America
| lat_deg = -17.6
| lon_deg = -63.8
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Petaca Formation
}}
{{Location map~ | South America
| lat_deg = -17.2
| lon_deg = -67.6
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Salla Formation
}}
{{Location map~ | South America
| lat_deg = -44.4
| lon_deg = -68.8
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Sarmiento Formation
}}
{{Location map~ | South America
| lat_deg = -36.6
| lon_deg = -69.7
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Agua de la Piedra Formation
}}
{{Location map~ | South America
| lat_deg = -22.5
| lon_deg = -45.5
| mark = Orange ff8040 pog.svg
| marksize = 10
| link = Tremembé Formation
}}
}}
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 Sarmiento Formation in the Golfo San Jorge Basin in central Patagonia, with other finds from the Petaca Formation of the Subandean Belt in Bolivia, the Salla Formation from the same country, the Moquegua Formation of the Moquegua Basin in southern Peru, the Agua de la Piedra Formation of the Neuquén Basin in Argentina, and the Tremembé Formation of the Taubaté Basin 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 crocodilians, snakes (Madtsoia), helmeted bull frogs, a catfish; Taubateia paraiba, and the caiman Caiman tremembensis. The Tremembé Formation is known for the preservation of several insects.
Gallery
{{left|
Rhynchippus equinus.jpg|Sketch of Rhynchippus by Frederic Brewster Loomis
}}
{{clearleft}}
Notes and references
{{Portal|Paleontology|Prehistoric mammals}}
= Notes =
{{reflist|group=note}}
= References =
{{reflist|20em}}
== Bibliography ==
{{commonscat|Rhynchippus|Rhynchippus}}
- {{Cite journal |last1=Martínez |first1=Gastón |last2=Dozo |first2=María Teresa |last3=Gelfo |first3=Javier N. |last4=Marani |first4=Hernán |year=2016 |title=Cranial Morphology of the Late Oligocene Patagonian Notohippid Rhynchippus equinus Ameghino, 1897 (Mammalia, Notoungulata) with Emphases in Basicranial and Auditory Region |journal=PLoS ONE |volume=11 |issue=5 |pages=1–29 |doi=10.1371/journal.pone.0156558 |pmid=27232883 |pmc=4883762 |doi-access=free |bibcode=2016PLoSO..1156558M }}
- {{cite book |last=Palmer |first=D. |display-authors=et al |year=1999 |title=The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals |publisher= Marshall Editions |location=London |pages=252}} {{ISBN|1-84028-152-9}}
- {{cite book |last1=Patterson |first1=Bruce D. |last2=Pires Costa |first2=Leonora |year=2012 |title=Bones, Clones, and Biomes: The History and Geography of Recent Neotropical Mammals |publisher=University of Chicago Press |pages=1–432}} {{ISBN|978-0226649191}}
{{Meridiungulata|N.|state=collapsed}}
{{Taxonbar|from=Q911486}}
Category:Oligocene mammals of South America
Category:Golfo San Jorge Basin
Category:Fossil taxa described in 1897
Category:Taxa named by Florentino Ameghino