This page deals with the stem group of the rhinoceroses (superfamily Rhinocerotoidea, suborder Ceratomorpha). Extant rhinoceroses comprise the family Rhinocerotidae, which is restricted today to five or six species living in eastern and southern Africa and subtropical and tropical Asia (Encyclopaedia Britannica).
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Many phylogenetic studies have been performed on fossil rhinoceroses. While there is general agreement on the phylogeny of the Rhinocerotidae family (see Lu, 2013; Becker et al, 2013; Lu et al, 2016;Tissier et al, 2020), there is little consensus on that of the ancestors of the Rhinocerotidae (compare Wang et al, 2016; Tissier et al, 2018; Bai et al, 2020; Deng et al, 2021; Tissier et al, 2021; Li et al, 2022; Veine-Tonizzo et al, 2023; Sun et al, 2023). The following time tree is a combination of pruned versions of two trees that are fairly representative of the range of interpretation:
​Figure 1. Time tree of the stem-Rhinocerotoidea
​The oldest member of the Rhinocerotoid stem group is Yimengia magna, described from the upper part of the Nomogen Formation of Early Eocene (Ypresian) age at the Nuhetingboerhe locality in the Erlian Basin of Inner Mongolia, China (Bai et al, 2020). This species is illustrated below, together with all other fossils represented in Figure 1 for which images are available in the public domain (click on image for larger view):
​Figure 2. Images of stem- Rhinocerotoidea
Subject to the uncertainty associated with the tree shown in Figure 1, the above images are placed in left-to-right order from most basal towards the crown group. The more basal members of the families ancestral to the Rhinocerotidae look very tapir-like (e.g. Teletaceras, Hyracodon nebraskensis), whereas the more crownward fossils are less like tapirs but do not show any clear trend.  It is only in the Rhinocerotidae that we see a clear resemblance to modern rhinos (e.g. Menoceras arikarense).

The oldest member of the crown-Rhinocerotoidea is represented by fossils of the extant species Rhinoceros unicornis, found in sediments of Early Pleistocene age in south China and parts of Indochina (Antoine, 2012). A living example of this species is illustrated in the page header above.
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The above time tree (Figure 1) indicates that the rhinoceros stem group developed from Early Eocene to Early Pleistocene time, representing a stem-to-crown transition of at least 49 million years.

References

Antoine, P. O. (2012). Pleistocene and Holocene rhinocerotids (Mammalia, Perissodactyla) from the Indochinese Peninsula. Comptes Rendus Palevol, 11(2-3), 159-168.

Bai, B., Meng, J., Zhang, C., Gong, Y. X., & Wang, Y. Q. (2020). The origin of Rhinocerotoidea and phylogeny of Ceratomorpha (Mammalia, Perissodactyla). Nature Communications Biology, 3(1), 509.

Becker, D., Antoine, P. O., & Maridet, O. (2013). A new genus of Rhinocerotidae (Mammalia, Perissodactyla) from the Oligocene of Europe. Journal of Systematic Palaeontology, 11(8), 947-972.
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Deng, T., Lu, X., Wang, S., Flynn, L. J., Sun, D., He, W., & Chen, S. (2021). An Oligocene giant rhino provides insights into Paraceratherium evolution. Nature Communications Biology, 4(1), 639.

Li, S., Jiangzuo, Q., & Deng, T. (2022). Body mass of the giant rhinos (Paraceratheriinae, Mammalia) and its tendency in evolution. Historical Biology, 1-12.

Lu, X. (2013). A juvenile skull of Acerorhinus yuanmouensis (Mammalia: Rhinocerotidae) from the Late Miocene hominoid fauna of the Yuanmou Basin (Yunnan, China). Geobios, 46(6), 539-548.

Lu, X., Zheng, X., Sullivan, C., & Tan, J. (2016). A skull of Plesiaceratherium gracile (Rhinocerotidae, Perissodactyla) from a new lower Miocene locality in Shandong Province, China, and the phylogenetic position of Plesiaceratherium. Journal of Vertebrate Paleontology, 36(3), e1095201.

Sun, D., Deng, T., & Wang, S. (2023). The first record of the genus Prosantorhinus (Perissodactyla: Rhinocerotidae) of East Asia. Zoological Journal of the Linnean Society, zlad183.

Tissier, J., Becker, D., Codrea, V., Costeur, L., Fărcaş, C., Solomon, A., ... & Maridet, O. (2018). New data on Amynodontidae (Mammalia, Perissodactyla) from Eastern Europe: Phylogenetic and palaeobiogeographic implications around the Eocene-Oligocene transition. PLoS One, 13(4), e0193774.

Tissier, J., Antoine, P. O., & Becker, D. (2020). New material of Epiaceratherium and a new species of Mesaceratherium clear up the phylogeny of early Rhinocerotidae (Perissodactyla). Royal Society Open Science, 7(7), 200633.

Tissier, J., Antoine, P. O., & Becker, D. (2021). New species, revision, and phylogeny of Ronzotherium Aymard, 1854 (Perissodactyla, Rhinocerotidae). European journal of taxonomy, 753, 1-80.

Veine-Tonizzo, L., Tissier, J., Bukhsianidze, M., Vasilyan, D., & Becker, D. (2023). Cranial morphology and phylogenetic relationships of Amynodontidae Scott and Osborn, 1883 (Perissodactyla, Rhinocerotoidea). Comptes Rendus. Palevol, 22(8), 109-142.

Wang, H., Bai, B., Meng, J., & Wang, Y. (2016). Earliest known unequivocal rhinocerotoid sheds new light on the origin of Giant Rhinos and phylogeny of early rhinocerotoids. Nature Scientific reports, 6(1), 39607.
Image credits – stem-Rhinocerotoidea
  • Header (Indian Rhinoceros (Rhinoceros unicornis) at Chester Zoo near Chester, UK): Hans Hillewaert, under Creative Commons Attribution-Share Alike 3.0 Unported license.
  • Figure 2 (Fouchia elyensis): https://www.si.edu/object/fouchia-elyensis-emry:nmnhpaleobiology_3427690, CC0, via Wikimedia Commons 
  • Figure 2 (Yimengia magna): Open Access article Bai, B., Meng, J., Zhang, C., Gong, Y. X., & Wang, Y. Q. (2020). The origin of Rhinocerotoidea and phylogeny of Ceratomorpha (Mammalia, Perissodactyla). Nature Communications Biology, 3(1), 509.
  • Figure 2 (Hyrachyus sp.): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons 
  • Figure 2 (Uintaceras radinskyi): A. C. Tatarinov, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
  • Figure 2 (Teletaceras sp.): Heinrich Harder (1858-1935), modified by A. C. Tatarinov, Public domain, via Wikimedia Commons
  • Figure 2 (Hyracodon nebraskensis, skeleton): Jonathan Chen, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Hyracodon nebraskensis, life restoration): Nobu Tamura, under Creative Commons Attribution- ShareAlike (CC BY-SA) license
  • Figure 2 (Forstercooperia totadentata): Rextron, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Gobioceras wangi): Open Access article Bai, B., Meng, J., Zhang, C., Gong, Y. X., & Wang, Y. Q. (2020). The origin of Rhinocerotoidea and phylogeny of Ceratomorpha (Mammalia, Perissodactyla). Nature Communications Biology, 3(1), 509.
  • Figure 2 (Pappaceras meiomenus, fossil): Open Access article Wang, H. B., Bai, B., Gong, Y. X., Meng, J., & Wang, Y. Q. (2017). Reconstruction of the cranial musculature of the paraceratheriid rhinocerotoid Pappaceras meiomenus and inferences of its feeding and chewing habits. Acta Palaeontologica Polonica, 62(2), 259-271.
  • Figure 2 (Pappaceras meiomenus, life restoration): Hai-Bing Wang, Bin Bai, Yan-Xin Gong, Jin Meng and Yuan-Qing Wang, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Amynodon advenus): Open Access article Campisano, C. J., Kirk, E. C., Townsend, K. B., & Deino, A. L. (2014). Geochronological and taxonomic revisions of the middle Eocene Whistler Squat Quarry (Devil’s Graveyard Formation, Texas) and implications for the early Uintan in Trans-Pecos Texas. PLoS One, 9(7), e101516.
  • Figure 2 (Cadurcodon ardynensis): MikSed, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Cadurcodon sp.): Apokryltaros at en.wikipedia, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons
  • Figure 2 (Metamynodon planifrons): Open Access article Veine-Tonizzo, L., Tissier, J., Bukhsianidze, M., Vasilyan, D., & Becker, D. (2023). Cranial morphology and phylogenetic relationships of Amynodontidae Scott and Osborn, 1883 (Perissodactyla, Rhinocerotoidea). Comptes Rendus. Palevol, 22(8), 109-142.
  • Figure 2 (Metamynodon sp.): Heinrich Harder (1858-1935), Public Domain
  • Figure 2 (Eggysodon gaudryi): Open Access article Antoine, P. O., Métais, G., Orliac, M. J., Peigné, S., Rafaÿ, S., Solé, F., & Vianey-Liaud, M. (2011). A new late Early Oligocene vertebrate fauna from Moissac, south-west France. Comptes Rendus Palevol, 10(4), 239-250.
  • Figure 2 (Paraceratherium transouralicum, fossil): Jonathan Chen, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Paraceratherium transouralicum, life restoration): ABelov2014 (https://abelov2014.deviantart.com/), CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
  • Figure 2 (Ronzotherium filholi): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
  • Figure 2 (Trigonias osborni): Michael Brett-Surman, CC0, via Wikimedia Commons
  • Figure 2 (Protaceratherium minutum): Ghedoghedo, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Menoceras arikarense, skeleton): James St. John, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
  • Figure 2 (Menoceras arikarense, life restoration): Robert Bruce Horsfall, Public domain, via Wikimedia Commons
  • Figure 2 (Hispanotherium matritense): PePeEfe, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Hispanotherium tungurense): Chen Yu (sinammonite on Deviantart), CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Eoazara xerrii): Denis Geraads, Samir Zouhri, Lilian Cazes, Philippe Loubry, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0>, da Wikimedia Commons
  • Figure 2 (Plesiaceratherium sp.): Ghedoghedo, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Brachydiceratherium shanwangense): Sizov, A., Klementiev, A., & Antoine, P. O. (2022). An Early Miocene skeleton of Brachydiceratherium Lavocat, 1951 (Mammalia, Perissodactyla) from the Baikal area, Russia, and a revised phylogeny of Eurasian teleoceratines. bioRxiv, 2022-07. License: Creative Commons Attribution-NoDerivatives 4.0 International
  • Figure 2 (Brachypotherium sp.): Ghedoghedo, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
  • Figure 2 (Prosantorhinus germanicus): Ghedoghedo, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
  • Figure 2 (Teleoceras fossiger, skeleton): https://www.si.edu/object/teleoceras-fossiger-cope:nmnhpaleobiology_3389708, CC0, via Wikimedia Commons
  • Figure 2 (Teleoceras fossiger, life restoration): karkemish00, Creative Commons Attribution-NonCommercial-No Derivatives Works 3.0 License