Hipparionini
{{Short description|Extinct tribe of mammals}}
{{automatic taxobox
| fossil_range = {{fossilrange|Early Miocene|Early Pleistocene}}
| image = Hipparion sp. - Batallones 10 fossil site, Torrejón de Velasco, Madrid, Spain.jpg
| taxon = Hipparionini
| authority = Quinn, 1955
| subdivision = See text
}}
Hipparionini is a tribe of three-toed horses in the subfamily Equinae. They had body forms similar to modern equines, with high-crowned teeth. They first appeared in North America during the Early Miocene around 17 million years ago,{{Cite journal |last1=Janis |first1=Christine M. |last2=Bernor |first2=Raymond L. |date=2019-04-12 |title=The Evolution of Equid Monodactyly: A Review Including a New Hypothesis |journal=Frontiers in Ecology and Evolution |volume=7 |doi=10.3389/fevo.2019.00119 |issn=2296-701X |doi-access=free |hdl=1983/ede09e37-96f7-4baf-aec5-1bb7766a04e7 |hdl-access=free }} before migrating into the Old World around 11.4-11.0 million years ago.{{Cite journal |last1=Bernor |first1=Raymond L. |last2=Kaya |first2=Ferhat |last3=Kaakinen |first3=Anu |last4=Saarinen |first4=Juha |last5=Fortelius |first5=Mikael |date=October 2021 |title=Old world hipparion evolution, biogeography, climatology and ecology |journal=Earth-Science Reviews |language=en |volume=221 |pages=103784 |doi=10.1016/j.earscirev.2021.103784|doi-access=free |bibcode=2021ESRv..22103784B }} The youngest species date to the Early Pleistocene, becoming extinct following the arrival of modern equines of the genus Equus to the Old World.{{Cite journal |last1=Cirilli |first1=Omar |last2=Pandolfi |first2=Luca |last3=Alba |first3=David M. |last4=Madurell-Malapeira |first4=Joan |last5=Bukhsianidze |first5=Maia |last6=Kordos |first6=Laszlo |last7=Lordkipanidze |first7=David |last8=Rook |first8=Lorenzo |last9=Bernor |first9=Raymond L. |date=April 2023 |title=The last Plio-Pleistocene hipparions of Western Eurasia. A review with remarks on their taxonomy, paleobiogeography and evolution |journal=Quaternary Science Reviews |language=en |volume=306 |pages=107976 |doi=10.1016/j.quascirev.2023.107976|s2cid=257594449 |doi-access=free |bibcode=2023QSRv..30607976C }}
Description
Hipparionines varied widely in size, with the smallest species like Hipparion periafricanum having a body mass of only {{Convert|23|kg|lb}}, considerably smaller than living equines,{{Cite journal |last=Orlandi-Oliveras |first=Guillem |last2=Nacarino-Meneses |first2=Carmen |last3=Koufos |first3=George D. |last4=Köhler |first4=Meike |date=2018-11-21 |title=Bone histology provides insights into the life history mechanisms underlying dwarfing in hipparionins |url=https://www.nature.com/articles/s41598-018-35347-x |journal=Scientific Reports |language=en |volume=8 |issue=1 |pages=17203 |doi=10.1038/s41598-018-35347-x |issn=2045-2322|pmc=6249282 }} while the largest species had body masses over {{Convert|300|kg|lb}}.
Evolutionary history
In North America, hipparionins were equally diverse to equins during the Middle Miocene but overtook them in species richness during the Late Miocene and Early Pliocene. At the end of the Hemphillian, hipparionins severely declined in diversity.{{Cite journal |last=Hulbert |first=Richard C. |date=Spring 1993 |title=Taxonomic evolution in North American Neogene horses (subfamily Equinae): the rise and fall of an adaptive radiation |url=https://www.cambridge.org/core/journals/paleobiology/article/abs/taxonomic-evolution-in-north-american-neogene-horses-subfamily-equinae-the-rise-and-fall-of-an-adaptive-radiation/86E64524FB79259675D8D928FE0A839F |journal=Paleobiology |language=en |volume=19 |issue=2 |pages=216–234 |doi=10.1017/S0094837300015888 |issn=0094-8373 |access-date=27 November 2024 |via=Cambridge Core|url-access=subscription }}
Ecology
In the Old World hipparionins were initially browsers and mixed feeders (both browsing and grazing), over time there was increasing proportion of pure grazers, though the groups ecology remained diverse, with mixed feeding being the dominant ecology during the Pliocene. Hipparionins in the western Mediterranean during the Vallesian and Turolian exhibited noticeable niche partitioning, with smaller forms being mixed feeders while larger species had more grazing diets. In contrast, contemporaneous eastern Mediterranean hipparionins did not exhibit such niche partitioning.{{Cite journal |last=Orlandi-Oliveras |first=Guillem |last2=Köhler |first2=Meike |last3=Clavel |first3=Julien |last4=Scott |first4=Robert |last5=Mayda |first5=Serdar |last6=Kaya |first6=Tanju |last7=Merceron |first7=Glidas |date=April 2022 |title=Feeding strategies of circum‑Mediterranean hipparionins during the late Miocene: Exploring dietary preferences related to size through dental microwear analysis |url=https://palaeo-electronica.org/content/2022/3591-hipparionin-dental-microwear |journal=Palaeontologia Electronica |doi=10.26879/990 |access-date=1 January 2025 |via=Palaeontologia Electronica}}
Taxonomy
North American genera:
- "Hipparion" (distinct from Old World species assigned to this genus)
- Neohipparion
- Pseudhipparion
- Nannippus
- Cormohipparion
Old World genera: (widely thought to descend from Cormohipparion)