Radinskya

Radinskya is an extinct perissodactyl-like mammal from the Paleocene of China (Nongshanian ALMA).[2][3] It is named after palaeontologist and perissodactyl expert Leonard Radinsky who died prematurely in 1985.[4]

Radinskya[1] Temporal range: Paleocene PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
(unranked):	Fereuungulata Euungulata Waddell et al. 1999
Genus:	†Radinskya McKenna et al. 1989
Species
†R. yupingae McKenna et al. 1989

Before the discovery of Radinskya, palaeontologists speculated on an American origin for the tethythere-perissodactyl radiation that took place during the Paleocene-Eocene transition (around 55 million years ago). The primitive Radinskya from China made it clear that this radiation began in Asia during the Paleocene, from where it spread to North America, Europe, and Africa during the Eocene. With its enigmatic position at the base of this radiation, Radinskya is a member of the Chinese Paleocene fauna which includes primitive tethytheres such as Minchenella and the oldest arsinoitheres; it shares many characters with perissodactyls and some with phenacolophids, but is too primitive to be called either a horse, a rhino, or a tapir.[4]

Radinskya is known only from a partial skull and upper dentition, which makes it difficult to assess its relationships to other fossils. Rose 2006 described the upper molars as "quadrate with a rhomboid outline and a weak, π-shaped crown pattern formed by the incipient ectoloph, protoloph, and metaloph (crests on the crowns). This arrangement closely resembles the crown pattern of early perissodactyls, but the strong conules (cusps) and some other characters suggest relationship to phenacolophids" and added that "Radinskya may be the sister taxon of all other Altungulata or may be closer to the origin of Perissodactyla than is any phenacodontid."[5]

Radinskya has also been included into the Embrithopoda, treated as an outgroup to perissodactyls.[6] Other Nongshanian phenacolophids include Yuelophus, Tienshanilophus, Ganolophus and the large form Minchenella.[2]

Notes

1. "Genus †Radinskya". The Taxonomicon. Retrieved 14 April 2013.
2. Lucas 2001, pp. 211–2
3. MacFadden 2005, p. 539
4. Prothero & Schoch 2002, p. 198
5. Rose 2006, pp. 243–4
6. Prothero, Manning & Fischer 1988 and Prothero & Schoch 1989, p. 510

References

• Lucas, Spencer G. (2001). Chinese fossil vertebrates. Columbia University Press. ISBN 9780231084833. Retrieved 14 April 2013.
• MacFadden, Bruce J. (2005). Janis, Christine Marie; Scott, Kathleen Marie; Jacobs, Louis L. (eds.). Evolution of Tertiary Mammals of North America: Terrestrial carnivores, ungulates, and ungulatelike mammals. 1. Cambridge University Press. ISBN 9780521355193. Retrieved 14 April 2013.
• McKenna, M.C.; Chow, M.; Ting, S.; Luo, Z. (1989). "Radinskya yupingae, a perissodactyl-like mammal from the late Paleocene of China". In Prothero, D.R.; Schoch, R.M. (eds.). The evolution of perissodactyls. Oxford monographs on geology and geophysics. 15. New York: Oxford University Press. pp. 24–36. ISBN 9780195060393. OCLC 19268080.
• Prothero, Donald R.; Manning, Earl M.; Fischer, Martin (1988). "The phylogeny of the ungulates" (PDF). In Benton, Michael J. (ed.). The Phylogeny and Classification of the Tetrapods, Volume 2. Mammals. The Systematics Association Special Volume Series. 35. Oxford: Clarendon Press. pp. 201–34. ISBN 9780198577126. Retrieved 14 April 2013.
• Prothero, Donald R.; Schoch, Robert M. (1989). "The origin and evolution of perissodactyls: a summary and synthesis" (PDF). In Prothero, D.R.; Schoch, R.M. (eds.). The evolution of perissodactyls. Oxford monographs on geology and geophysics. 15. New York: Oxford University Press. pp. 504–529. ISBN 9780195060393. OCLC 19268080. Retrieved 14 April 2013.
• Prothero, Donald R.; Schoch, Robert M. (2002). Horns, Tusks, and Flippers. JHU Press. ISBN 9780801871351. Retrieved 14 April 2013.
• Rose, Kenneth David (2006). The beginning of the age of mammals. Baltimore: JHU Press. ISBN 0801884721.
• Waddell, Peter J.; Cao, Ying; Hauf, Jöerg; Hasegawa, Masami (1999). "Using Novel Phylogenetic Methods to Evaluate Mammalian mtDNA, Including Amino Acid-Invariant Sites-LogDet plus Site Stripping, to Detect Internal Conflicts in the Data, with Special Reference to the Positions of Hedgehog, Armadillo, and Elephant". Systematic Biology. 48 (1): 31–53. doi:10.1080/106351599260427. PMID 12078643. Retrieved 14 April 2013.