Pygmy elephant

from Wikipedia, the free encyclopedia
Skeleton of a Sicilian pygmy elephant ( Palaeoloxodon falconeri )

As dwarf elephants a series of mostly extinct, diminutive Rüsseltier forms that have evolved during the ice age on different islands is called. They mostly belong to the genera Palaeoloxodon and Mammuthus , but dwarfed representatives from other trunk lines have also been documented. Two forms living today, the " Borneo dwarf elephant " and the African "dwarf elephant", are controversial in their taxonomic position.

Island dwarf elephants

Skeleton of a Crete dwarf mammoth ( Mammuthus creticus )

A series of small elephants of the genera Palaeoloxodon and Mammuthus are referred to as dwarf elephants or better island dwarf elephants . The dwarfism is an adaptation to the reduced habitat on the islands, the reduced food supply and the absence of predators. Such reduced island shapes occurred more frequently as a result of a process known as island dwarfing in the course of the proboscis evolution . B. the stegodons on the islands of Southeast Asia . In addition to the elephants, other large mammals, such as the hippopotamus with the species Hippopotamus melitensis , were also subject to the process of island dwarfing on some Mediterranean islands . However, such populations are vulnerable to changes in environmental conditions such as natural disasters or human influences.

Island elephants of the Mediterranean

In the Pleistocene, dwarf forms lived on some islands in the Mediterranean, most of which developed from the European forest elephant ( Palaeoloxodon antiquus ). There are also species, albeit less often, that can be traced back to the genus Mammuthus . Their initial forms can be the southern elephant ( Mammuthus meridionalis ) on the one hand, and the steppe mammoth ( Mammuthus trogontherii ) on the other .

Dwarf elephants

One of the best-known dwarf relatives of the European forest elephant is u. a. the Sicilian dwarf elephant ( Palaeoloxodon falconeri ) with a shoulder height of about one meter and a weight of about 170 kg. This species occurred on both Sicily and Malta , both of which formed a more closely closed geographical area in the cold periods of the Pleistocene, when the sea level was significantly lower than it is today. The species originated in the middle Pleistocene in a first phase of geographical isolation. A second phase of isolation led to the formation of the species Palaeoloxodon mnaidriensis in the late Pleistocene in Sicily and Malta , which measured a little less than 2 m at the shoulder and weighed up to 2.5 t. In contrast, Elephas melitensis , which was previously described as the Maltese dwarf elephant, is identical to Palaeoloxodon mnaidriensis .

There were also similar forms on the Aegean islands of the Dodecanese, some of which are tiny today, such as Tilos , Rhodes and Kalymnos, and the Cyclades , such as Delos and Naxos . More closely examined is Palaeoloxodon tiliensis from Tilos with a shoulder height of 1.4 m and a reconstructed weight of 650 kg. One of the youngest dated skeletons from the island of Tilos has an age of 2400 BC. The last evidence is around 1300 BC. It is therefore possible that Bronze Age cultures of the Mediterranean area encountered these pygmy elephants and had something to do with their extinction; Whether representations on ancient Egyptian wall paintings show such dwarf elephants is still a point of contention. The skulls of the pygmy elephants could have contributed to the origin of the Mediterranean saga of the Cyclops in ancient times, as elephants have a single nostril in the middle of their forehead, which can easily be misinterpreted as an eye. Most of the other forms have not yet been named, only the finds from Naxos were described in 2014 as Palaeoloxodon lomolinoi , which was only 10% the size of a European forest elephant.

A very small dwarf form weighing only 250 kg was Palaeoloxodon cypriotes from Cyprus , which lived until about 9500 BC. Can be proven and was possibly exterminated by the first settlers of the island. Palaeoloxodon xylophagou represents a second dwarf form in Cyprus. This reached somewhat larger dimensions and dates to the Middle Pleistocene. In contrast, Palaeoloxodon creutzburgi from the Young Pleistocene of Crete was less dwarfed. It reached about 69% of the body size of the mainland forms, weight estimates range on the basis of the found long bones up to about 3 t. Finds from the neighboring island of Kassos to the east may also be assigned to the same species . Palaeoloxodon chaniensis was also reported from Crete . Its taxonomic independence is controversial. The shape surpassed Palaeoloxodon creutzburgi somewhat in size. From the Ionian island of Kefalonia in the Gulf of Patras , the species Palaeoloxodon cephallonicus was introduced in 2018 , which lived in the transition from the Middle to the Young Pleistocene. So far it is only known from an upper jaw enclosed in a rock matrix. Their dimensions corresponded roughly to those of Palaeoloxodon creutzburgi or Palaeoloxodon mnaidriensis .

Dwarf mammoths

One of the representatives of the mammoths including the Late Pleistocene in on Sardinia occurring mammuthus lamarmorai which was about 1.5 meters tall and weighed about kg 800th Another representative was the heavily dwarfed Crete dwarf mammoth ( Mammuthus creticus ) from the early Pleistocene, which was originally controversial in its taxonomic position and which was identified a few years ago as a species that actually belonged to the mammoths by means of molecular genetic studies (see aDNA ). According to recent studies, this mammoth species is the smallest known form of this genus of proboscis with a shoulder height of 1.1 m and a weight of around 310 kg.

Island elephants in the Arctic Ocean

The woolly mammoth ( Mammuthus primigenius ) developed a dwarf island variant on the Siberian Wrangel Island in the Arctic Ocean , on which the last population of this species survived until about 4,000 years ago, long after the mammoth became extinct on the mainland. These animals reached a shoulder height of around 1.8 m with a weight of a good 2 t. Representatives of the woolly mammoth on the Pribilof Islands off the coast of Alaska , which also only died out in the Holocene, but a little earlier than the mammoths of Wrangel Island, were slightly larger .

Island elephants in the Pacific Ocean

Mammuthus exilis lived on the Channel Islands off the coast of California in the Young Pleistocene . This dwarf form was between 1.2 and 1.8 m tall and probably goes back to the prairie mammoth ( Mammuthus columbi ) of the North American mainland. The mammoth species became extinct at the end of the Pleistocene.

Island elephants of the Southeast Asian Archipelago

A dwarf elephant species from the Pleistocene of Southeast Asia has been reported from Sulawesi , the former Celebes. Originally designated as Elephas celebensis , some scientists now classify them as an independent genus Stegoloxodon due to the structure of their teeth . This also includes some finds from Java . In addition, dwarfed relatives of the elephants, who are counted among the stegodons , also appeared on various other islands such as Timor , Sumba or Flores at the time . One example is Stegodon florensis , which weighed around 300 kg. All species are extinct. The " Borneo dwarf elephants " ( Elephas maximus borneensis ) living on Borneo are an assumed subspecies of the Asian elephant ( Elephas maximus ). Their systematic status is uncertain, and there is also a debate as to whether it is an endemic population or animals introduced by humans. In terms of body size, they hardly differ from their relatives on the Southeast Asian mainland.

African "dwarf elephant"

In 1906 Theophil Noack described a small individual of an African elephant under the scientific name Elephas africanus pumilio . The animal lived in the Hamburg zoo , but originally came from what is now the Republic of the Congo . The small size of the animal prompted Noack to view its new form as a "dwarf elephant". The "dwarf elephant" was later renamed Loxodonta pumilio . A controversial debate has long raged about its actual existence. According to proponents, the "dwarf elephant " lived in the tropical rainforests of central Africa and shared its habitat there with the forest elephant ( Loxodonta cyclotis ). This was supported by the occasional sighting of smaller animals with trained tusks. Opponents, on the other hand, rejected its existence and justified this, among other things, with the fact that the type specimen of Loxodonta pumilio had grown even further during its lifetime and had a shoulder height of over 2 m at the time of its death. They saw it as a young animal of the forest elephant. At the turn of the 20th to the 21st century, anatomical comparisons of the forest elephant with the "dwarf elephant" did not reveal any differences between the two forms. Molecular genetic studies also showed that the “dwarf elephant” is identical to the forest elephant. Today researchers see the occasional sightings of smaller elephants in the Congo Basin as orphaned juveniles or as pathologically dwarfed individuals of the forest elephant.

literature

  • Jordi Augusti: Mammoths, Sabertooths and Hominids 65 Million Years of Mammalian Evolution in Europe . Columbia University Press, New York NY et al. 2002, ISBN 0-231-11640-3
  • Erich Thenius: Basics of the fauna and distribution history of mammals. Gustav Fischer, Stuttgart 1980, ISBN 3-437-30312-0
  • Harald Gebhardt and Mario Ludwig: Of dragons, yetis and vampires - on the trail of mythical animals . BLV-Verlag, Munich, 2005, ISBN 3-405-16679-9

Individual evidence

  1. ↑ George Zammit Maempel: Għar Dalam. Cave and deposits. Malta, 1989
  2. ↑ a b c d e f g h i Maria Rita Palombo: Elephants in miniature. In: Harald Meller (Hrsg.): Elefantenreich - Eine Fossilwelt in Europa. Halle / Saale, 2010, pp. 275–295
  3. ↑ Lucia Caloi, Tassos Kotsakis, Maria Rita Palombo and Carmelio Petronio: The Pleistocene dwarf elephants of Mediterranean islands. In: Jeheskel Shoshani and Pascal Tassy (eds.): The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford, New York, Tokyo, 1996, pp. 234-239
  4. ↑ George Theodorou, Nikolaos Symeonidis and Elizabeth Stathopoulou: Elephas tiliensis n. Sp. from Tilos (Dodecanese, Greece). Hellenic Journal of Geosciences 42, 2007, pp. 19-32
  5. ↑ GE Theodorou: The fossil dwarf elephants of the “Charkadio” cave on the island of Tilos , Athens 1983 (= dissertation at the Dodekanes Univ.).
  6. ↑ Baruch Rosen: Mammoths in ancient Egypt? Nature 369, 1994, pp. 364-365
  7. ↑ Hans Dietrich Kahlke: The Ice Age. Leipzig, Jena, Berlin, 1981
  8. ↑ Alexandra AE van der Geer, George A. Lyras, Lars W. van den Hoek Ostende, John de Vos and Hara Drinia: A dwarf elephant and a rock mouse on Naxos (Cyclades, Greece) with a revision of the palaeozoogeography of the Cycladic Islands (Greece) during the Pleistocene. Palaeogeography, Palaeoclimatology, Palaeoecology 404 (15), 2014, pp. 133-144
  9. ^ A b Sevket Sen Eric Barrier and Xavier Crété: Late Pleistocene Dwarf Elephants from the Aegean Islands of Kassos and Dilos, Greece. Annales Zoologici Fennici 51 (1/2), 2014, pp. 27-42
  10. ^ A b Sevket Sen: A review of the Pleistocene dwarfed elephants from the Aegean islands, and their paleogeographic context. Fossil Imprint 73 (1/2), 2017; Pp. 76-92
  11. ↑ a b c Athanassios Athanassiou, Alexandra AE van der Geer and George A. Lyras: Pleistocene insular Proboscidea of ​​the Eastern Mediterranean: A review and update. Quaternary Science Reviews 218, 2019, pp. 306-321
  12. ↑ Athanassios Athanassiou, Victoria Herridge, David S. Reese, George Iliopoulos, Socrates Roussiakis, Vassiliki Mitsopoulou, Efthymios Tsiolokis and George Theodorou: Cranial evidence for the presence of a second endemic elephant species on Cyprus. Quaternary International 379, 2015, pp. 47-57
  13. ↑ George Theodorou, Yiannis Bassiakos, Evangelos Tsakalos, Evyenia Yiannouli and Petros Maniatis: The Use of CT Scans and 3D Modeling as a Powerful Tool to Assist Fossil Vertebrate Taxonomy. In: Marinos Ioannides, Eleanor Fink, Raffaella Brumana, Petros Patias, Anastasios Doulamis, João Martins and Manolis Wallace (eds.): Digital heritage. Progress in cultural heritage: documentation, preservation, and protection. 7th International Conference, EuroMed 2018, Nicosia, Cyprus, October 29 – November 3, 2018, Proceedings, Part I. Springer, 2018, pp. 79–89
  14. ^ R. Melis, Maria Rita Palombo and M. Mussi: Mammuthus lamarmorae (Major, 1883) remains in the pre-Tyrrhenian deposits of San Giovanni in Sinis (Western Sardinia, Italy). In: G. Cavarretta et al. (Ed.): The World of Elephants - International Congress. Consiglio Nazionale delle Ricerche. Rome, 2001, pp. 481-485
  15. ↑ Nikos Poulakakis et al .: Ancient DNA forces reconsideration of evolutionary history of Mediterranean pygmy elephantids. Biology Letters 2 (3), 2006, pp. 451-454 doi: 10.1098 / rsbl.2006.0467
  16. ↑ Victoria L. Herridge and Adrian M. Lister: Extreme insular dwarfism evolved in a mammoth. Proceedings of the Royal Society series B 279 (1741), pp. 3193-3200 doi: 10.1098 / rspb.2012.0671
  17. ^ Adrian M. Lister: Mammoths in miniature. Nature 362, 1993, pp. 288-289
  18. ↑ JM Enk, DR Yesner, KJ Crossen, DW Veltre and DH O'Rourke: Phylogeographic Analysis of the mid-Holocene Mammoth from Qagnax Cave, St. Paul Island, Alaska. Palaeogeography, Palaeoclimatology, Palaeoecology 273 (1-2), 2009, pp. 184-190
  19. ^ V. Louise Roth: Pleistocene dwarf elephants from the California Islands. In: Jeheskel Shoshani and Pascal Tassy (eds.): The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford, New York, Tokyo, 1996, pp. 249-253
  20. ^ Georgi N. Markov and Haruo Saegusa: On the validity of Stegoloxodon Kretzoi, 1950 (Mammalia: Proboscidea). Zootaxa 1861, 2008, pp. 55-56
  21. ^ Earl of Cranbrook, J. Payne, and Charles MU Leh: Origin of the elephants Elephas maximus L. of Borneo. Sarawak Museum Journal 63, 2007, pp. 95-125
  22. ↑ Reeta Sharma, Benoit Goossens, Rasmus Heller, Rita Rasteiro, Nurzhafarina Othman, Michael W. Bruford and Lounès Chikhi: Genetic analyzes favor an ancient and natural origin of elephants on Borneo. Scientific Reports 8, 2018, p. 880 doi: 10.1038 / s41598-017-17042-5
  23. ^ Theophil Noack: A dwarf form of the African elephant. Annals and Magazine of Natural History 17, 1906, pp. 501–503 ( online )
  24. ↑ L. Blancou: A propos des formes naines de l'éléphant d'Afrique. Mammalia 26, 1962, pp. 343-361
  25. ^ E. Bourdelle and F. Petter: Note relative à un éléphant nain du Gabon. Mammalia 13, 1950, pp. 144-153
  26. ^ Pierre Pfeffer: Sur la validité de formes naines de l'éléphant d'Afrique. Mammalia 24, 1960, pp. 556-576
  27. ↑ Colin P. Groves and Peter Grubb: Are there pygmy elephants ?. Elephant 2 (4), 2000, pp. 8-10
  28. ↑ Régis Debruyne, Arnaud Van Holt, Véronique Barriel and Pascal Tassy: Status of the so-called African pygmy elephant (Loxodonta pumilio (NOACK 1906)): phylogeny of cytochrome b and mitochondrial control region sequences. Comptes Rendus Biologies 326, 2003, pp. 687-697

Web links