''Elephas celebensis'', the Sulawesi dwarf elephant, is an extinct

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

elephant Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are the only surviving members of the family Elephantidae ...

Description

''Elephas celebensis'' (sometimes referred as ''Stegoloxodon celebensis'') was about half the size of '' Archidiskodon planifrons'', to which both were initially considered to be related by Dirk Albert Hooijer in 1949. The most evident difference with the latter species is the presence of functional lower

tusk Tusks are elongated, continuously growing front teeth that protrude well beyond the mouth of certain mammal species. They are most commonly canine teeth, as with pigs and walruses, or, in the case of elephants, elongated incisors. Tusks share ...

s in some individuals. This was considered to be caused by

paedomorphosis Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...

, a retention of juvenile characters in the adult stage, by Vincent Maglio in his revision of the proboscideans in 1973. He based his conclusion on the presence of vestigial incisive germs in mandibles of ''Mammuthus planifrons''. This idea was followed by Hooijer in 1974.

Ancestry and taxonomy

The retention of functional lower tusks is, however, not seen in juveniles of otherwise single pair-tusked individuals, so the said characters cannot be considered a paedomorphic feature proper. It is simply a retention of a primitive character, as seen in the African elephantid genera ''

Primelephas ''Primelephas'' is a genus of Elephantinae that existed during the Miocene and Pliocene epochs. The name of the genus suggests 'first elephant'. These primitive elephantids are thought to be the common ancestor of ''Mammuthus'', the mammoths ...

'' and ''

Stegotetrabelodon ''Stegotetrabelodon'' is an extinct genus of primitive elephantid with gomphothere-like anatomical features from the Late Miocene to Early Pliocene of Africa and Eurasia and the Arabian peninsula. The type species is ''S. syrticus'' of late Mioc ...

'', and possibly the earliest forms of ''Elephas planifrons''. Between the late 1980s and early 1990s, an Indonesian-Dutch team excavated more material, including a fairly complete but rather distorted skull. All material, new as well as old, is described and revised in Van den Bergh’s thesis of 1999 on the Indonesian elephantoids, with a discussion on taxonomy. He puts question marks ( as in “''Elephas''”) to indicate the uncertain taxonomical position, following Paul Sondaar’s approach of 1984. Van den Bergh accepts a possible relation with the supposed “''Elephas''” ''indonesicus'' from Ci Pangglosoran near Bumiayu,

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mos ...

, dated to the same geological period. Also this specimen was originally assigned to ''Elephas planifrons'', but was later renamed ''Stegoloxodon indonesicus'' by Kretzoi in 1950. Recently, Georgi Markov and Haruo Saegusa made a further step and synonymized “''Elephas''” with ''Stegoloxodon'' in 2008.

Distribution

In general, elephantids under the supposed ''Stegoloxodon'' group has been known to be restricted to

Van der Maarel, F.H., 1932. Contributions to the knowledge of the fossil mammalian fauna of Java. Wetenschappelijke Mededelingen Dienst van den Mijnbouw in Nederlandsch-Indie 15: 1-208. and Sulawesi. The exact relations between the two species is somewhat unclear, since the Javan species is only known from a single molar. Specifically, fossils of ''E. celebensis'' have been found in the Walanea Formation, dated to the

Late Pliocene Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

- Early Pleistocene.

References

{{Taxonbar, from=Q5359440 Prehistoric elephants Piacenzian first appearances Pleistocene extinctions Cenozoic mammals of Asia Extinct animals of Indonesia Fossil taxa described in 1949