Ungulates

from Wikipedia, the free encyclopedia

Ungulates (Ungulata) is the collective term for several groups of mammals , and in particular the cloven and the Perissodactyla . The distinction between these two main groups is old: in the case of odd-toed ungulates, the middle toe alone bears the body weight; in the case of even-toed ungulates, the third and fourth toes take over this function.

Discussion about the ungulates as a systematic unit

Until the end of the 20th century, the ungulate taxon , which was mostly undisputed and based on the formation of the hooves , does not form a self-contained group according to molecular genetic studies. According to this, the ungulates represent a unit of groups of mammals with different relationships, brought together according to external criteria. The term “ungulates” or “ungulata” is often only used informally.

18th and 19th centuries

An order of ungulates was first drawn up by Carl von Linné in the 12th edition of Systema naturae ( 1766 ). Even after Richard Owen had shaped the separation of even- toed and odd-toed ungulates in the 19th century, it was still assumed that these orders belonged together in a higher-level taxon. In the late 19th century, the ungulates eventually comprised the following orders:

20th century

Grzimek's animal life put these and a number of fossil orders into a system of five superordinate orders:

  • Primeval ungulates (Protungulata), with tubular teeth and five fossil groups; this use of the term "primeval hoofed animals" is not identical to the usual meaning in which he only means the extinct collective taxon of the condylar arthra, as in the Wikipedia article primeval hoofed animals .
  • Amblypoda (Amblypoda), with four fossil orders
  • Almost ungulates ( Paenungulata ), with the snails, manatees and proboscis
  • Central axis animals (Mesaxonia), only with the odd-toed ungulates
  • Double-axed animals (Paraxonia), only with the even-toed ungulates

The terms “primordial ungulates” and “almost ungulates” suggest that these are preliminary stages of the ungulates on an evolutionary ladder, which has thus found its completion in pair and unpaired ungulates. While such a view is incompatible with modern systematic theory, there are zoologists to this day who put up a monophyletic taxon ungulata. So the Ungulata exist as "major order" ( grand order ) nor in the scheme of McKenna and Bell of 1997. Here they include the aforementioned regulations, supplemented by the whales .

Current discussion

Internal systematics of the Euungulata according to Welker et al. 2015
  Euungulata  
  Cetartiodactyla  

 Artiodactyla  (Artiodactyla) 


   

 Whales  (cetacea) 



  Panperissodactyla  

 Unpaired ungulate (Perissodactyla)


   

 " Meridiungulata " (South American ungulates †; especially Notoungulata and Litopterna




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Due to molecular genetic studies, however, a relationship which was recently Perissodactyla (Perissodactyla) with the Cetartiodactyla ( cloven-hoofed animals (Artiodactyla) and whales (Cetacea)) found. Waddell and colleagues named the clade of Perissodactyla and Artiodactyla Euungulata (real ungulates). According to studies that were published in March 2015, the odd ungulates are again closely related to Macrauchenia from the Litopterna group and Toxodon from the Notoungulata group . Both belong to the so-called Meridiungulata ("South American ungulates"), a very diverse group of crouching mammals occurring in South America from the Paleocene to the Pleistocene , the systematic uniformity of which has not yet been clarified. Both kinship groups, the odd-toed ungulates and the "South American ungulates" are now combined in the higher-level taxon of Panperissodactyla . This family group is opposite to the Cetartiodactyla within the Euungulata.

Level of knowledge

According to modern opinion, there is therefore a high probability of a taxon (the Euungulata) that includes at least two of the orders traditionally counted as ungulates. Then there are the whales, which have a common ungulate-like ancestor with the recent even-toed ungulates, and the extinct South American ungulates. Proboscis, manatees, tubular teeth and hyrax, on the other hand, belong to the Afrotheria , a molecular-genetic hierarchy within mammals, whose ancestral origin lies in Africa.

literature

  • Ronald M. Nowak: Walker's Mammals of the World . Johns Hopkins University Press, 1999 ISBN 0-8018-5789-9
  • Malcolm C. McKenna, Susan K. Bell: Classification of Mammals: Above the Species Level . Columbia University Press, 2000 ISBN 0-231-11013-8
  • Bernhard Grzimek: Grzimeks animal life. Encyclopedia of the Animal Kingdom . Bechtermünz, 2001 ISBN 3-8289-1603-1

Individual evidence

  1. Malcolm C. McKenna and Susan K. Bell: Classification of mammals above the species level. Columbia University Press, New York, 1997, pp. 1-631 (pp. 357-502)
  2. Michael J. Stanhope, Victor G. Waddell, Ole Madsen, Wilfried de Jong, S. Blair Hedges, Gregory C. Cleven, Diana Kao and Mark S. Springer: Molecular evidence for multiple origins of Insectivora and for a new order of endemic African insectivore mammals. PNAS 95, 1998, pp. 9967-9972
  3. Jump up ↑ a b Frido Welker, Matthew J. Collins, Jessica A. Thomas, Marc Wadsley, Selina Brace, Enrico Cappellini, Samuel T. Turvey, Marcelo Reguero, Javier N. Gelfo, Alejandro Kramarz, Joachim Burger, Jane Thomas-Oates, David A. Ashford, Peter D. Ashton, Keri Rowsell, Duncan M. Porter, Benedikt Kessler, Roman Fischer, Carsten Baessmann, Stephanie Kaspar, Jesper V. Olsen, Patrick Kiley, James A. Elliott, Christian D. Kelstrup, Victoria Mullin, Michael Hofreiter, Eske Willerslev, Jean-Jacques Hublin, Ludovic Orlando, Ian Barnes and Ross DE MacPhee: Ancient proteins resolve the evolutionary history of Darwin's South American ungulates. Nature , 2015 DOI: 10.1038 / nature14249
  4. Peter J. Waddell, Hirohisa Kishino and Rissa Ota: A Phylogenetic Foundation for Comparative Mammalian Genomics. Genome Informatics 12, 2001, pp. 141-154