Embrithopoda
Temporal range: Eocene - Oligocene, 56–28 Ma[1]
Arsinoitherium zitteli[2]
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Clade: Paenungulata
Order: Embrithopoda
Andrews 1906
Families

Embrithopoda ("heavy-footed") is an order of extinct mammals known from Asia, Africa and Eastern Europe. Most of the embrithopod genera are known exclusively from jaws and teeth dated from the late Paleocene to the late Eocene; however, the order is best known from its terminal member, the elephantine Arsinoitherium.[3]

Description

While embrithopods bore a superficial resemblance to rhinoceroses, their horns had bony cores covered in keratinized skin and were not made of hair. Not all embrithopods possessed horns, either. Despite their appearance, they have been regarded as related to elephants, not perissodactyls.[4]

As tethytheres,[5] the Embrithopoda have been believed to be part of the clade Afrotheria. However, a study of the basal arsinoitheriid, Palaeoamasia, suggests that embrithopods are not tethytheres or even paenungulates, and that they need to be better sampled in an analysis of eutherian relationships to clarify if they are even afrotherians.[6] It is also not clear if embrithopods originated in Africa or Eurasia.[6] However, recent findings demonstrate an African origin for embrithopods and furthermore a relationship with other paenungulates, albeit having diverged earlier than previously thought.[7]

Fossils of embrithopods, such as Arsinoitherium, have been found in Egypt, Ethiopia, Morocco, Mongolia, Turkey, Romania, Namibia[8] and Tunisia.[9] Until the 1970s, only Arsinoitherium itself was known, appearing isolated in the fossil record.[4]

Classification

McKenna & Manning 1977 and McKenna & Bell 1997 considered Phenacolophus from Mongolia a primitive embrithopod, although this attribution was challenged by several other authors.[10] A 2016 cladistic study found Phenacolophus as a stem-perissodactyl and the embrithopods at the base of Altungulata.[11][6] More recently, an afrothere identity has been vindicated, albeit more basal than previously assumed.[12]

Order Embrithopoda Andrews 1906 sensu Prothero & Schoch 1989 (=Barypoda Andrews 1904)[13]

Notes

  1. ^ Emmanuel Gheerbrant; Arnaud Schmitt; László Kocsis (2018). "Early African fossils elucidate the origin of embrithopod mammals". Current Biology. Online edition. doi:10.1016/j.cub.2018.05.032.
  2. ^ Rose 2006, pp. 242–3
  3. ^ Rose 2006, p. 265
  4. ^ a b "Introduction to the Embrithopoda". University of California Museum of Paleontology. Retrieved 7 March 2013.
  5. ^ Embrithopoda in the Paleobiology Database. Retrieved March 2013.
  6. ^ a b c Erdal, O.; Antoine, P.-O.; Sen, S.; Smith, A. (2016). "New material of Palaeoamasia kansui (Embrithopoda, Mammalia) from the Eocene of Turkey and a phylogenetic analysis of Embrithopoda at the species level". Palaeontology. 59 (5): 631–655. doi:10.1111/pala.12247.[Erdal et al.'s inclusion of Embrithopoda in Tabuce et al. (2007) finds them outside of (Ungulata + Afrotheria). Since this clade is not supported by molecular data, it suggests the need to explore the relationships of embrithopods, as they could potentially have affinities with laurasiatheres and "true" ungulates.]
  7. ^ E. Gheerbrant, A. Schmitt, and L. Kocsis. 2018. Early African Fossils Elucidate the Origin of Embrithopod Mammals. Current Biology 28:1-7
  8. ^ a b M. Pickford; B. Senut; J. Morales; P. Mein; I. M. Sanchez (2008). "Mammalia from the Lutetian of Namibia". Memoir of the Geological Survey of Namibia. 20: 465–514.
  9. ^ Nicolas Vialle; Gilles Merzeraud; Cyrille Delmer; Monique Feist; Suzanne Jiquel; Laurent Marivaux; Anusha Ramdarshan; Monique Vianey-Liaud; El Mabrouk Essid; Wissem Marzougui; Hayet Khayati Ammar; Rodolphe Tabuce (2013). "Discovery of an embrithopod mammal (Arsinoitherium?) in the late Eocene of Tunisia". Journal of African Earth Sciences. 87: 86–92. doi:10.1016/j.jafrearsci.2013.07.010.
  10. ^ Koenigswald, W. v. (2012). "Unique differentiation of radial enamel in Arsinoitherium (Embrithopoda, Tethytheria)". Historical Biology. 25 (2): 183–192. doi:10.1080/08912963.2012.714658.
  11. ^ Radulesco & Sudre 1985; Maas, Thewissen & Kappelman 1998, p. 291; Rose & Archibald 2005, pp. 97–98
  12. ^ E. Gheerbrant, A. Schmitt, and L. Kocsis. 2018. Early African Fossils Elucidate the Origin of Embrithopod Mammals. Current Biology 28:1-7
  13. ^ Mikko's Phylogeny Archive [1] Haaramo, Mikko (2007). "†Embrithopoda - arsinoitheres". Retrieved 30 December 2015.

References