Raoellidae
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, the best preserved Raoellid, from Kashmir suggests that Raoellids are the "missing link" sister group to whales (Cetacea).[3] 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 Raoellids and later fully adapted to aquatic life.
Taxonomy
- Raoella
- Raoella dograi
- Rajouria
- Rajouria gunelli
- Haqueina?
- Haqueina haquei?
- Indohyus
- Indohyus indirae
- Indohyus major
- Kunmunella
- Kunmunella kalakotensis
- Kunmunella transversa
- Metkatius
- Metkatius kashmiriensis
- Khirtharia
- Khirtharia aurea
- Khirtharia dayi
- Khirtharia inflatus
- Khirtharia major?
Phylogeny
In 2011 a study was published examining the remains of a possible raoellid from China. After a phylogenetic analysis, they found it to be most closely related to previously named species of Khirtharia, placing it under this genus as the new species K. major. The phylogenetic tree that resulted from their analysis placed Haqueina outside of Raoellidae in the clade Dichobunidae, a group of artiodacyls not closely related to Cetaceans. The study did not include Raoella or Rajourna.[4]
It found that Raoellidae is monophyletic. Kunmunella is the most basal member of Raoellidae, followed by Indohyus, and then Metkatius and Kirtharia.[4]
References
- ^ "PBDB". paleobiodb.org. Retrieved 2021-07-23.
- ^ Sahni et al. 1981.
- ^ Thewissen et al. 2007
- ^ a b "(PDF) Eocene raoellids (Mammalia, Cetartiodactyla) outside the Indian Subcontinent: Palaeogeographical implications". ResearchGate. Archived from the original on 2023-12-10. Retrieved 2025-04-27.
Sources
- Dehm, Richard; Oettingen-Spielberg, Therese zu (1958). Paläontologische und geologische Untersuchungen im Tertiär von Pakistan. 2. Die mitteleocänen Säugetiere von Ganda Kas bei Basal in Nordwest-Pakistan. Abhandlungen / Neue Folge, 91. Munich: Beck. OCLC 163296508.
- Kumar, K.; Sahni, A. (1985). "Eocene mammals from the upper Subathu Group, Kashmir Himalaya, India". Journal of Vertebrate Paleontology. 5 (2): 153–68. doi:10.1080/02724634.1985.10011853. OCLC 4649653478.
- Pilgrim, G. E. (1940). "Middle Eocene mammals from north-west Pakistan". Proceedings of the Zoological Society. B. 110. London: 127–152.
- Rao, A Ranga (1971). "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): 124–34.
- Rana, R. S.; Waqas, M.; Orliac, M.; Folie, A.; Smith, T. (2021). "A new basal raoellid artiodactyl (Mammalia) from the middle Eocene Subathu Group of Rajouri District, Jammu and Kashmir, northwest Himalaya, India" (PDF). Geobios. 66–67: 193–206. Bibcode:2021Geobi..66..193R. doi:10.1016/j.geobios.2020.12.003. S2CID 233516820.
- Sahni, A.; Bhatia, S. B.; Hartenberger, J. L.; Jaeger, J. J.; Kumar, K.; Sudre, J.; Vianey-Liaud, M. (1981). "Vertebrates from the Subathu Formation and comments on the biogeography of Indian subcontinent during the early Paleogene". Bulletin of the Geological Society of France. 23 (6): 689–95. doi: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, JGM; Cooper, Lisa Noelle; Clementz, Mark T; Bajpai, Sunil; Tiwari, BN (20 December 2007). "Whales originated from aquatic artiodactyls in the Eocene epoch of India" (PDF). Nature. 450 (7173): 1190–4. doi:10.1038/nature06343. OCLC 264243832. PMID 18097400. S2CID 4416444. Retrieved 29 June 2013.