Ruminantia

Ruminantia is a taxon within the order Artiodactyla that includes many of the well-known large grazing or browsing mammals: among them cattle, goats, sheep, deer, and antelope. All members of the Ruminantia employ foregut fermentation and are ruminants: they digest food in two steps, chewing and swallowing in the normal way to begin with, and then regurgitating the semidigested cud to rechew it and thus extract the maximum possible food value.

Ruminantia
Temporal range: Early Eocene - present
White-tailed deer
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Clade: Ruminantiamorpha
Spaulding et al., 2009
Suborder: Ruminantia
Scopoli, 1777
Families

Evolution

Ruminantiamorpha is a total clade of artiodactyls defined, according to Spaulding et al., as "Ruminantia plus all extinct taxa more closely related to extant members of Ruminantia than to any other living species."[1] Spaulding grouped some genera of the family Anthracotheriidae within Ruminantiamorpha (but not in Ruminantia), but placed others within Ruminantiamorpha's sister clade, Cetancodontamorpha.

The Tragulidae are the basal family in Ruminantia.[2] The ancestral Ruminantia karyotype is 2n = 48, similar to that of ancestral cetartiodactyls.[2]

   Artiodactyla   
 

 Tylopoda

 
   Artiofabula   
 

 Suina    

 
   Cetruminantia   
 

 Ruminantia

 
   Whippomorpha   
 

 Hippopotamidae

 
 

 Cetacea

 
 
 
 
 

Not all ruminants belong to the Ruminantia.[3] Tylopoda (such as camels, which chew a cud) and Hippopotamidae (such as hippopotami, which do not chew a cud) are classified as pseudoruminants.[3] A number of other large grazing mammals, e.g. horses and kangaroos, employ hindgut fermentation as an adaptation for surviving on large quantities of low-grade food.

The digestive system of ruminants is composed of:[4]

  • Bovine buccal cavity (upper and lower parts).
  • Bovine duodenal papilla.
  • Goat liver.
  • Ovine stomach.
  • Sheep liver.
  • Didactic model of a bovine Rumen and Reticulum.
  • Didactic model of a bovine omasum and abomasum.
  • Bovine liver.

References
  1. "Relationships of Cetacea (Artiodactyla) among mammals: increased taxon sampling alters interpretations of key fossils and character evolution". PLoS ONE. 4 (9): e7062. 2009. doi:10.1371/journal.pone.0007062. PMC 2740860. PMID 19774069.
  2. Kulemzina, Anastasia I.; Yang, Fengtang; Trifonov, Vladimir A.; Ryder, Oliver A.; Ferguson-Smith, Malcolm A.; Graphodatsky, Alexander S. (2011). "Chromosome painting in Tragulidae facilitates the reconstruction of Ruminantia ancestral karyotype". Chromosome Research. 19 (4): 531–539. doi:10.1007/s10577-011-9201-z. ISSN 0967-3849.
  3. Whistler, D. P. and S. D. Webb. 2005. New goatlike camelid from the late Pliocene of Tecopa Lake Basin, California. Natural History Museum of Los Angeles County Contributions in Science 503:1-40.
  4. "Ruminant anatomy and physiology : Dairy Extension : University of Minnesota Extension". www.extension.umn.edu. Retrieved 2017-05-08.
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