Dwarf elephants are prehistoric members of the order Proboscidea which, through the process of allopatric speciation on islands, evolved much smaller body sizes (around shoulder height) in comparison with their immediate ancestors. Dwarf elephants are an example of insular dwarfism, the phenomenon whereby large terrestrial vertebrates (usually mammals) that colonize islands evolve dwarf forms, a phenomenon attributed to adaptation to resource-poor environments and lack of predation and competition.
Fossil remains of dwarf elephants have been found on the Mediterranean islands of Cyprus, Malta, Crete, Sicily, Sardinia, the Cyclades Islands and the Dodecanese Islands, which are mostly members of the genus Palaeoloxodon, descending from the large tall straight-tusked elephant (Palaeoloxodon antiquus) of mainland Europe, though two species represent dwarf mammoths. Dwarf species of elephants and Stegodon have been found on the islands of Indonesia and the Philippines, with dwarfed species of Stegodon also having been found in Japan. The Channel Islands of California once supported the pygmy mammoth, a dwarf species descended from Columbian mammoths, while the woolly mammoths that existed on Wrangel Island north of Siberia were once considered dwarfs, but are not anymore.
The Mediterranean islands
Dwarf elephants first inhabited the Mediterranean islands during the Pleistocene, including all the major islands with the apparent exception of Corsica and the Balearics. Mediterranean dwarf elephants have generally been considered as members of the genus Palaeoloxodon, derived from the continental straight-tusked elephant, Palaeoloxodon antiquus (Falconer & Cautley, 1847), Syn.: Elephas antiquus. An exception is the dwarf Middle-Late Pleistocene Sardinian mammoth, Mammuthus lamarmorai (Major, 1883), the first endemic elephant of the Mediterranean islands recognized as belonging to the mammoth line. Mammuthus creticus from the Early Pleistocene of Crete, formerly considered a member of Palaeoloxodon, is now also considered to be a mammoth, and approaches the size of the smallest dwarf elephants.
During low sea levels, the Mediterranean islands were colonised again and again, giving rise, sometimes on the same island, to several species (or subspecies) of different body sizes. The island of Sicily appears to have been colonised by proboscideans in at least two separate waves of colonisation. These endemic dwarf elephants were taxonomically different on each island or group of very close islands, like the Cyclades archipelago.
There are many uncertainties about the time of colonisation, the phylogenetic relationships and the taxonomic status of dwarf elephants on the Mediterranean islands. Extinction of the insular dwarf elephants has not been correlated with the arrival of humans to the islands, with the exception of Palaeoloxodon cypriotes on Cyprus, which survived until human colonisation of the island around 12,000 years ago.
Palaeontologist Othenio Abel proposed in 1914 that the finding of skeletons of such elephants sparked the idea that they belonged to giant one-eyed monsters, because the center nasal opening was thought to be the socket of a single eye, and thus perhaps were, for example, the origin of the one-eyed Cyclopes of Greek mythology.Abel's surmise is noted by Adrienne Mayor in The First Fossil Hunters: Paleontology in Greek and Roman Times (Princeton University Press) 2000. [See illus. ed., 2001: ] While this claim has been widely been repeated, it has been criticised for lacking evidence.
Italy and Malta Island Taxon Author Sardinia Mammuthus lamarmorai (, 1883) Malta Palaeoloxodon falconeri (, 1869) Palaeoloxodon mnaidriensis (, 1874) Sicily Palaeoloxodon falconeri (, 1869) Palaeoloxodon cf. mnaidriensis (, 1874) Sicily and Malta were inhabited by two successive waves of dwarf elephants derived from P. antiquus, which first arrived on the islands at least 500,000 years ago. The first of these species is P. falconeri , which is one of the smallest dwarf elephant species at around tall, and was strongly modified from its ancestor in numerous aspects, which lived in a depauperate fauna with no other large mammal species.Bonfiglio, L., Marra, A. C., Masini, F., Pavia, M., & Petruso, D. (2002). Pleistocene faunas of Sicily: a review. In W. H. Waldren, & J. A. Ensenyat (Eds.), World islands in prehistory: international insular investigations. British Archaeological Reports, International Series, 1095, 428–436. Later, around 200,000 years ago, this species was replaced by a second colonisation by P. antiquus, which gave rise to the larger (though still considerably dwarfed) tall species P. mnaidriensis, which on Sicily lived alongside a number other large mammal species, including herbivores and carnivores. The youngest records of this species on Sicily date to around 20,000 years ago, close to the time of arrival of modern humans on Sicily.
The dwarf mammoth species Mammuthus lamarmorai descended from steppe mammoths (Mammuthus trogontherii) that colonised Sardinia sometime after 450,000 years ago. It is suggested to have survived into the Last Glacial Period, until at least 60-30,000 years ago.
Greece Crete Island Taxon Author Crete Mammuthus creticus (, 1907) Palaeoloxodon creutzburgi (, 1965)
Mammuthus creticus is known from remains probably dating to the Early Pleistocene. It likely descends from Mammuthus meridionalis. It is the smallest mammoth and is among the smallest dwarf elephants known, with a shoulder height of about and a weight of about . Palaeoloxodon creutzburgi from the Middle Pleistocene and Late Pleistocene is significantly larger, with an estimated body mass comparable to living Asian elephant, around 40% the size of its mainland ancestor.
Cyclades Island Taxon Author Delos Palaeoloxodon sp. , 1929 Naxos Palaeoloxodon lomolinoi et al., 2014 Paros Elephantidae indet. , 1929 Kythnos Elephantidae indet. , 1975 Milos Elephantidae indet. , 1953 Serifos Elephantidae indet. , 1953
Remains of dwarf elephants have been briefly reported from Paros, Milos and Serifos in historical publications, but these lack any detailed information.
On Kýthnos, the remains of a dwarf elephant were reported in a 1975 publication to be found associated with lithic artefacts. The age of the find was considered to be uncertain, likely older than 9,000 years, but could not be dated precisely due to a lack of collagen. Additionally, an isolated tusk was reported from the northwest of the island.
On Delos, an indeterminate dwarf elephant known from a third molar was reported in 1908. This specimen clearly belongs to a dwarf species, but it is difficult to quantify its size precisely. On Naxos the species Palaeoloxodon lomolinoi has been described based on a partial skull including the maxilla bones and third molar teeth found near the Trypiti river, of probable Late Pleistocene age. It is estimated to be around 8% the size of P. antiquus, and had a smaller body size than that represented by the dwarf elephant from Delos. The Eastern Cyclades islands of Delos, Naxos, and Paros were connected during the Last Glacial Period, which suggests that the Delos species and P. lomolinoi were not contemporaneous, with the former possibly being the ancestor of the latter, though nothing can be said for certain.
Dodecanese Island Taxon Author Astypalaia Palaeoloxodon sp. et al., 2019 Kasos Palaeoloxodon aff. creutzburgi et al., 2014 Rhodes Palaeoloxodon sp. et al., 1974 Tilos Palaeoloxodon tiliensis ( et al. 2007)
On Rhodes, bones of an unnamed endemic dwarf elephant have been discovered in cave deposits on the east coast. This elephant was similar in size to Palaeoloxodon mnaidriensis (to which its remains were originally attributed), around 20% the size of its mainland ancestor (with an estimated weight of around ). The remains, though temporally poorly constrained, are suggested to be Late Pleistocene age. Possible tracks produced by these dwarf elephants have been reported from the southwest of the island.
On Tilos, the species Palaeoloxodon tiliensis has been described from remains found in Charkadio cave.G. Theodorou, N. Symeonidis, E. Stathopoulou Elephas tiliensis n. sp. from Tilos island (Dodecanese, Greece) Hell. J. Geosci., 42 (2007), pp. 19-32 This species was medium-sized, around 10% the size of P. antiquus, with a shoulder height of up to , with a body mass of . Remains of the species are suggested to date to Late Pleistocene. Radiocarbon dating done in the 1970s suggested that the species survived until around 3,500 years ago, which would make the latest surviving Palaeoloxodon species and the youngest elephant in Europe, but these dates are tentative and await corroboration by other research.
On Astypalaia, a single tusk of a dwarf elephant of unknown age was excavated in the late 1990s. Due to the isolated status of the island it very likely represents an endemic species. Though the size of the animal is difficult to constrain precisely, it was probably similar in size to P. tiliensis.
On Kasos, which during the Pleistocene was connected with the islands of Karpathos and Saria, a single dwarf Palaeoloxodon molar has been found. Due to the tooth closely resembling those of the species P. creutzburgi from Crete (which is adjacent to Kasos) in size and shape, it has been referred to as P. aff. creutzburgi.
Cyprus Island Taxon Author Cyprus Palaeoloxodon cypriotes (, 1903)Bate, D. M. A.: Preliminary Note on the Discovery of a Pigmy Elephant in the Pleistocene of Cyprus in Proceedings of the Royal Society of London Vol. 71 (1902 - 1903), pp. 498-500 Palaeoloxodon xylophagou et al., 2015
The Cyprus dwarf elephant (Palaeoloxodon cypriotes) survived at least until 12,000 years ago, around the time of arrival of modern humans to Cyprus (who may have hunted it), making it one of the latest surviving dwarf elephants. It is also one of the smallest dwarf elephant species, comparable in size to P. falconeri, with an estimated shoulder height of . The species likely evolved from the earlier larger (though still strongly dwarfed) Palaeoloxodon xylophagou known from fossils dating to around 200,000 years ago.
Remains of the species were first discovered and recorded by Dorothea Bate in a cave in the Kyrenia hills of northern Cyprus in 1902 and reported in 1903.Dorothea Bate, Cyprus work diary 1901–02, 3 volumes, Natural History Museum's earth sciences library, palaeontology MSS
The Channel Islands of California
A population of the Columbian mammoth (Mammuthus columbi) arrived on the northern Channel Islands of California during the late Middle Pleistocene, around 250-150,000 years ago, giving rise to a dwarfed species, the pygmy mammoth (Mammuthus exilis). Channel Islands mammoths ranged from in shoulder height. These mammoths became extinct around 13,000 years ago, around the time of arrival of modern humans to the islands.
Indonesia and the Philippines In Indonesia and the Philippines, evidence of a succession of distinct endemic island faunas has been found, including dwarfed elephants and species of Stegodon.
Flores