Elephantinae

Elephantinae is a subfamily of mammals in the family Elephantidae and includes the largest existing land animals. Three species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Elephantidae is the only surviving family of the order Proboscidea; extinct members include the mastodons. The family Elephantidae also contains several now-extinct groups, including the mammoths and straight-tusked elephants. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears, and convex or level backs. Distinctive features of all elephants include a long trunk, tusks, large ear flaps, massive legs, and tough but sensitive skin. The trunk, also called a proboscis, is used for breathing, bringing food and water to the mouth, and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. The pillar-like legs carry their great weight.

For further information, see Elephantidae.

Elephantinae
Temporal range:
An African bush elephant (Loxodonta africana) in the wild at Mikumi National Park in Tanzania
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Proboscidea
Family: Elephantidae
Subfamily: Elephantinae
Gray, 1821
Type genus
Elephas
Subgroups[1]
Synonyms[2]
  • Elephasidae Lesson, 1842

Elephants may be listed or indexed by many criteria, including taxonomy, status as endangered species, their geographical location, and their portrayal and/or naming in human culture.

Classification
See also: List of elephant species and Elephants
"Man, and the elephant" plate from Hawkins A comparative view of the human and animal frame, 1860
Skeleton of Mammuthus meridionalis at the French Museum of Natural History

Scientific classification of Elephantidae taxa embraces an extensive record of fossil specimens, over millions of years, some of which existed until the end of the last ice age. Some species like the woolly mammoth were extirpated more recently. The discovery of new specimens and proposed cladistics have resulted in systematic revisions of the family and related proboscideans.

Elephantids are classified informally as the elephant family, or in a paleobiological context as elephants and mammoths. The common name elephant primarily refers to the living taxa, the modern elephants, but may also refer to a variety of extinct species, both within this family and in others. Other members of the Elephantidae, especially members of Mammuthus, are referred to by the common name mammoth.

The family diverged from a common ancestor of the mastodons of Mammutidae. The classification of proboscideans is unstable and has been frequently revised.

The following cladogram shows the placement of the genus Mammuthus among other proboscideans, based on hyoid characteristics:[1]

Elephantidae
Elephantinae
Loxodontini

Loxodonta (2 species)

  (African elephants)  
Elephantini
†Palaeoloxodontina        

†Palaeoloxodon

Elephantina
Elephas

(3~6 subspecies)

  (Asian elephants)  
†Mammuthus

  (Mammoths)  
The most accurate phylogenetic tree of the elephants and mammoths as of 2010

The systematics of the living subspecies and species of the modern elephants has undergone several revisions. A list of the extant Elephantidae includes:[3]

Elephantidae
Loxodonta (African)
L. africana African bush elephant
L. a. pharaoensis North African elephant†
L. cyclotis African forest elephant
Elephas (Asiatic)
E. maximus Asian elephant
E. m. maximus Sri Lankan elephant
E. m. indicus Indian elephant
E. m. sumatranus Sumatran elephant
E. m. borneensis Borneo elephant
E. m. sondaicus Javan elephant†
E. m. asurus Syrian elephant†

Evolutionary history
Evolution of elephants from the ancient Eocene (bottom) to the modern day (top)

Although the fossil evidence is uncertain, by comparing genes, scientists have discovered evidence that elephantids and other proboscideans share a distant ancestry with Sirenia (sea cows) and Hyracoidea (hyraxes).[4] These have been assigned, along with the extinct demostylians and embrithopods, to the clade Paenungulata. In the distant past, members of the various hyrax families grew to large sizes, and the common ancestor of all three modern families is thought to have been some kind of amphibious hyracoid. One hypothesis is that these animals spent most of their time under water, using their trunks like snorkels for breathing.[5][6] Modern elephants have this ability and are known to swim in that manner for up to six hours and 50 km (31 mi).

In the past, a much wider variety of genera and species was found, including the mammoths and stegodons.[7][8]

See also

References
  1. Shoshani, J.; Ferretti, M.P.; Lister, A.M.; Agenbroad, L.D.; Saegusa, H.; Mol, D.; Takahashi, K. (2007). "Relationships within the Elephantinae using hyoid characters". Quaternary International. 169–170: 174–185. Bibcode:2007QuInt.169..174S. doi:10.1016/j.quaint.2007.02.003.
  2. Maglio, Vincent J. (1973). "Origin and Evolution of the Elephantidae". Transactions of the American Philosophical Society. 63 (3): 16. doi:10.2307/1006229. JSTOR 1006229.
  3. Shoshani, J. (2005). "Order Proboscidea". In Wilson, D.E.; Reeder, D.M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.
  4. Ozawa, Tomowo; Hayashi, Seiji; Mikhelson, Victor M. (1997-04-24), "Phylogenetic Position of Mammoth and Steller's Sea Cow Within Tethytheria Demonstrated by Mitochondrial DNA Sequences", Journal of Molecular Evolution, 44 (4): 406–413, Bibcode:1997JMolE..44..406O, doi:10.1007/PL00006160, PMID 9089080, S2CID 417046
  5. West, John B. (2001), "Snorkel breathing in the elephant explains the unique anatomy of its pleura", Respiratory Physiology, 126 (1): 1–8, doi:10.1016/S0034-5687(01)00203-1, PMID 11311306
  6. West, John B.; Fu, Zhenxing; Gaeth, Ann P.; Short, Roger V. (2003-11-14), "Fetal lung development in the elephant reflects the adaptations required for snorkeling in adult life", Respiratory Physiology & Neurobiology, 138 (2–3): 325–333, doi:10.1016/S1569-9048(03)00199-X, PMID 14609520, S2CID 24902376
  7. Todd, N. E. (2001). African Elephas recki: time, space and taxonomy Archived 2008-12-16 at the Wayback Machine (pdf). In: Cavarretta, G., P. Gioia, M. Mussi, and M. R. Palombo. The World of Elephants, Proceedings of the 1st International Congress. Consiglio Nazionale delle Ricerche. Rome, Italy.
  8. Todd, N. E. (2005). Reanalysis of African Elephas recki: implications for time, space and taxonomy. Quaternary International 126-128:65-72.
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