Serbelodon

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Serbelodon
Temporal occurrence
Middle and Upper Miocene
15.97 million years to 7.246,000 years
Locations
Systematics
Tethytheria
Russell animals (Proboscidea)
Elephantimorpha
Elephantida
Gomphotheria (Gomphotheriidae)
Serbelodon
Scientific name
Serbelodon
Frick , 1933

Serbelodon is a now extinct genus of proboscis thatoccurredin the Middle and Lower Miocene around 15 to 8 million years ago in East Asia and Western North America .

features

Serbelodon was similar to the related genus Amebelodon , but had a shorter lower jaw with a very short symphysis and smaller tusks. These were shovel-shaped and had a continuous saddle on the top. The molars had characteristic enamel folds , giving the teeth a lophodontic structure. The last molar (M3) had four or five such enamel folds, while the others had three each.

Paleobiology

The shovel-like tusks were probably used for digging in the mud and lifting plant matter out of the water. This assumption was first made on the basis of specific signs of wear on the tusks and was supported by later isotope studies on the molars. The fluctuation values ​​of the 13 C and 18 O isotopes determined in these analyzes were very low. This suggests that Serbelodon lived partly amphibiously in more or less closed landscapes on the banks of waters and mainly fed on a mixed vegetable diet, which, due to the very low values ​​for the oxygen isotope, also included a larger amount of aquatic plants . On the other hand, studies on the signs of wear on the tusks suggest an individually variable diet, which also includes digging in harder substrates.

Systematics

Serbelodon belongs to the Amebelodontinae , a subfamily of the Gomphotheriidae , which are characterized by shovel-like tusks in the lower jaw. Here again they represent a part of the trilophodont gomphotheria with three enamel folds on the anterior molars. Within the Amebelodontinae, Serbelodon forms a closely related clade with Archaebelodon , Amebelodon and Protanacus .

Serbelodon was first described in 1933 by Childs Frick on the basis of finds from the Ash Hollow Formation , which come from the "Christmas Quarry" quarry in Cherry County ( Nebraska ). These include a fragmented skull and a lower jaw ( holotype copy number F: AM 25728). Heinz Tobien equated the genus with Amebelodon in 1972 with reference to only little separating characteristics . Numerous paleontologists, however, still use Serbelodon as a valid taxon . The reasons for this are, in addition to individual features in the structure of the molars, the shorter and not so strongly flattened lower jaw tusks, which appear less developed than those in Amebelodon .

Several species have been described by Serbelodon :

  • Serbelodon barbourensis Frick , 1933
  • Serbelodon zhongningensis Guan , 1986
  • Serbelodon burnhami Osborn , 1933

The species Serbelodon burnhami was named in honor of the American scout Frederick Russell Burnham . It is now mostly assigned to the genus Amebelodon .

The earliest evidence of Serbelodon can be found around 15 million years ago in China , one of the oldest sites is Wudaoling in the Ningxia Autonomous Region . It first appeared in North America 12 million years ago, but it is only known from a few sites in California and Nebraska . The most recent evidence here is 8 million years old, in East Asia it probably became extinct 11 million years ago.

literature

  • Henry Fairfield Osborn: Serbelodon Burnhami, a new Shovel-Tusker from California. American Museum Novitates 639, 1933, pp. 1–5 ( PDF file; 764 kB ).

Individual evidence

  1. ^ A b c W. David Lambert: The biogeography of the gomphotheriid proboscideans of North America. In: Jeheskel Shoshani and Pascal Tassy (eds.): The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford, New York, Tokyo, 1996, pp. 143-148
  2. ↑ a b c Zachary Kita: New Stable Isotope Record of aleoecological Change in the Late Neogene of the Western Great Plains from Enamel in Large Mammals. University of Nebraska 2011 ( [1] )
  3. ^ W. David Lambert: The Feeding Habits of the Shovel-Tusked Gomphotheres: Evidence from Tusk Wear Pattern. Paleobiology 18 (2), 1992, pp. 132-147
  4. ↑ María Teresa Alberdi, José Luis Prado, Edgardo Ortiz-Jaureguizar, Paula Posadas and Mariano Donato: Paleobiogeography of trilophodont gomphotheres (Mammalia: Proboscidea). A reconstruction applying DIVA (Dispersion-Vicariance Analysis). Revista Mexicana de Ciencias Geológicas 28 (2), 2011, pp. 235–244
  5. ↑ Shiqi Wang, Wen He and Shanqin Chen: The gomphotheriid mammal Platybelodon from the Middle Miocene of Linxia Basin, Gansu, China. Acta Palaeontologica Polonica 58 (2), 2013, pp. 221–240 ( [2] )
  6. ^ Jan van der Made: The evolution of the elephants and their relatives in the context of a changing climate and geography. In: Harald Meller (Hrsg.): Elefantenreich - Eine Fossilwelt in Europa. Halle / Saale, 2010, pp. 340-360
  7. ^ Daniel S. Fisher: Extinction of proboscideans in North America. In: Jeheskel Shoshani and Pascal Tassy (eds.): The Proboscidea. Evolution and palaeoecology of the Elephants and their relatives. Oxford, New York, Tokyo, 1996, pp. 296-315

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