Raoellidae Explained

The Raoellidae, previously grouped within Helohyidae, are an extinct family of semiaquatic digitigrade artiodactyls in the clade Whippomorpha. Fossils of raoellids are found in Eocene strata of South Asia and Southeast Asia.

An exceptionally complete skeleton of Indohyus from Kashmir suggests that raoellids are the "missing link" sister group to whales (Cetacea). All other Artiodactyla are relatives of these two groups. δO¹⁸ values and osteosclerotic bones indicate that the raccoon-like Indohyus was habitually aquatic. However, it is still unclear if Indohyus primarily fed on land or in water. It is hypothesized that cetaceans evolved from ancestors similar to Indohyus and later fully adapted to aquatic life.

Taxonomy

• Raoella
  • Raoella dograi
• Haqueina
  • Haqueina haquei
• Indohyus
  • Indohyus indirae
  • Indohyus major
• Kunmunella
  • Kunmunella kalakotensis
  • Kunmunella transversa
• Metkatius
  • Metkatius kashmiriensis
• Khirtharia
  • Khirtharia aurea
  • Khirtharia dayi
  • Khirtharia inflatus

Further reading

• Book: Dehm . Richard . Oettingen-Spielberg . Therese zu . Paläontologische und geologische Untersuchungen im Tertiär von Pakistan. 2. Die mitteleocänen Säugetiere von Ganda Kas bei Basal in Nordwest-Pakistan . 1958 . Munich . Beck . Abhandlungen / Neue Folge, 91 . 163296508 .
• Kumar . K. . Sahni . A. . Eocene mammals from the upper Subathu Group, Kashmir Himalaya, India . 1985 . Journal of Vertebrate Paleontology . 5 . 2 . 153–68 . 10.1080/02724634.1985.10011853 . 4649653478 .
• Pilgrim . G. E. . Middle Eocene mammals from north-west Pakistan . 1940 . Proceedings of the Zoological Society . London . B . 110 . 127–152 .
• Rao . A Ranga . New mammals from Murree (Kalakot Zone) of the Himalayan foot hills near Kalakot, Jammu and Kashmir state, India . Journal of the Geological Society of India . 12 . 2 . 1971 . 124–34 .
• Sahni . A. . Bhatia . S. B. . Hartenberger . J. L. . Jaeger . J. J. . Kumar, K. . Sudre, J. . Vianey-Liaud, M. . Vertebrates from the Subathu Formation and comments on the biogeography of Indian subcontinent during the early Paleogene . 1981 . Bulletin of the Geological Society of France . 23 . 6 . 689–95 . 10.2113/gssgfbull.S7-XXIII.6.689 .
• Sahni . A. S. H. O. K. . Khare . S. K. . 1971 . Three new Eocene mammals from Rajauri District, Jammu and Kashmir . Journal of the Palaeontological Society of India . 16 . 41–53 .
• Thewissen . Hans Thewissen . JGM . Cooper . Lisa Noelle . Clementz . Mark T . Bajpai . Sunil . Tiwari, BN . Whales originated from aquatic artiodactyls in the Eocene epoch of India . 20 December 2007 . Nature . 450 . 7173 . 1190–4 . 29 June 2013 . 10.1038/nature06343 . 18097400 . 4416444 . 264243832 .