Difference between revisions of "Ungulate" - New World Encyclopedia

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Ungulates, or hoofed mammals, are members of the orders Perissodactyla and Artiodactyla. Ungulates include most of the large land mammals on earth and all of the large domestic animals kept by humans. They are found naturally on all continents except Antartica and Australia (where they were introduced by humans) and in almost all environments from forests to grasslands to deserts to high mountains to the tundra. They range in size from the Lesser Malay mouse deer, Tragulus javanicus, which weighs 1.5 to 2.5 kg (3.3 to 5.5 lbs) fully grown to the White rhinoceros, Ceratotherium simum, and the Hippotomus, Hippopotamus amphibius, which can weigh over 3,200 kg (7,000 lbs) (Huffman 2006).

Closely related to ungulates are the orders:

Tubulidentata - Aardvark
Hyracoidea - Hyraxes
Proboscidea - Elephants
Sirenia - Sea cows
Cetacea - Whales and Dolphins

Ungulate features

The word "ungulate" comes from the Latin word ungula meaning "hoof". A hoof is a claw or nail which protects the toe and enables it to support the weight of the animal. Ungulates stand and run on the tips of their toes. This gives them longer legs which helps them to run faster.

Ungulates are typically herbivores, eating plants; some, such as the pigs, are omnivores, eating a variety of foods including meat.

Perissodactyla: odd-toed ungulates

?

Odd-toed ungulates

Plains Zebras

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla Owen, 1848

Families

Equidae
Tapiridae
Rhinocerotidae
Brontotheriidae † (extinct)
Chalicotheriidae †
Hyracodontidae †

In the Perissodactyla, the odd-toed ungulates, the central axis of the foot passes through the third toe.

Evolution

The odd-toed ungulates arose in what is now North America in the late Paleocene, less than 10 million years after the dinosaurs died out. By the start of the Eocene (55 million years ago) they had diversified and spread out to occupy several continents. The horses and tapirs both evolved in North America; the rhinoceroses appear to have developed in Asia from tapir-like animals and then spread to the Americas during the middle Eocene (about 45 million years ago). There were 12 families, of which only three survive. These families were very diverse in form and size; they included the enormous Brontotheres and the bizarre Chalicotheres. The largest perissodactyl, an Asian rhinoceros called Paraceratherium, reached 11,000 kg (12 tons), more than twice the weight of an elephant.

Perissodactyls were the dominant group of large terrestrial browsers right through the Oligocene. However, the rise of grasses in the Miocene (about 20 million years ago) saw a major change: the even-toed ungulates with their more complex stomachs were better able to adapt to a coarse, low-nutrition diet, and soon rose to prominence. Nevertheless, many odd-toed species survived and prospered until the late Pleistocene (about 10,000 years ago) when they faced the pressure of human hunting and habitat change.

Today there are only 17 species of odd-toes ungulates still living and all of them are in danger of extinction except for the horse and the donkey (UCMP 2006).

Taxonomy

The members of the order fall into two suborders:

Hippomorpha are odd-toed ungulates that are fast runners with long legs and have only one toe; this suborder has the sole family Equidae (coextensive with the genus Equus), comprising the horse, zebra, donkey, onager, and allied species.
Ceratomorpha are odd-toed ungulates that have several functional toes and are heavier than and move slower than the Hippomorpha species. This suborder has two families: Tapiridae (tapirs) and Rhinocerotidae (rhinoceroses)

Even-toed ungulates

?

Even-toed ungulates

240px
Rocky Mountain Goat, Oreamnos americanus

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla Owen, 1848

Families

Antilocapridae
Bovidae
Camelidae
Cervidae
Giraffidae
Hippopotamidae
Moschidae
Suidae
Tayassuidae
Tragulidae
Leptochoeridae † (extinct)
Chaeropotamidae †
Dichobunidae †
Cebochoeridae †
Entelodontidae †
Anoplotheriidae †
Anthracotheriidae †
Cainotheriidae †
Agriochoeridae †
Merycoidodontidae †
Leptomerycidae †
Protoceratidae †
Xiphodontidae †
Amphimerycidae †
Gelocidae †
Merycodontidae †
Dromomerycidae †

The even-toed ungulates form the mammal order Artiodactyla. They are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in perissodactyls. There are about 220 artiodactyl species, including many that are of great economic importance to humans.

As with many mammal groups, even-toed ungulates first appeared during the Early Eocene (about 54 million years ago). In form they were rather like today's chevrotains: small, short-legged creatures that ate leaves and the soft parts of plants. By the Late Eocene (46 million years ago), the three modern suborders had already developed: Suina (the pig group); Tylopoda (the camel group); and Ruminantia (the goat and cattle group). Nevertheless, artiodactyls were far from dominant at that time: the odd-toed ungulates (ancestors of today's horses and rhinos) were much more successful and far more numerous. Even-toed ungulates survived in niche roles, usually occupying marginal habitats, and it is presumably at that time that they developed their complex digestive systems, which allowed them to survive on lower-grade feed.

The appearance of grasses during the Eocene and their subsequent spread during the Miocene (about 20 million years ago) saw a major change: grasses are very difficult to digest and the even-toed ungulates with their highly-developed stomachs were better able to adapt to this coarse, low-nutrition diet, and soon replaced the odd-toed ungulates as the dominant terrestrial herbivores.

The artiodactyls fall into two groups which, despite underlying similarities, are rather different. The Suina (pigs, hippos, and peccaries) retain four toes, have simpler molars, short legs, and their canine teeth are often enlarged to form tusks. In general, they are omnivores and have a simple stomach (the two hippopotamus species and the babirusa are exceptions). It is possible that Suina is not a natural group. In particular, recent research suggests that the Hippopotamidae (which are likely derived from among the extinct group known as anthracotheres) may be more closely related to the ruminants than to the pigs.

The camelids and the Ruminantia, on the other hand, tend to be longer-legged, to have only two toes, to have more complex cheek teeth well-suited to grinding up tough grasses, and multi-chambered stomachs. Not only are their digestive systems highly developed, they have also evolved the habit of chewing cud: regurgitating partly-digested food to chew it again and extract the maximum possible benefit from it.

Lastly a group of artiodactyls, which molecular biology suggests were most closely related to Hippopotamidae, returned to the sea to become whales. The conclusion is that Artiodactyla, if it excludes Cetacea, is a paraphyletic group. For this reason, the term Cetartiodactyla was coined to refer to the group containing both artiodactyls and whales (though the problem could just as easily be resolved by recognizing Cetacea as a subgroup of Artiodactyla).

ORDER ARTIODACTYLA
- Suborder Suina
  - Family Suidae: pigs
  - Family Hippopotamidae: hippos
  - Family Tayassuidae: peccaries
- Suborder Tylopoda
  - Family Camelidae: camels and llamas
- Suborder Ruminantia
  - Family Tragulidae: chevrotains
  - Family Moschidae: musk deer
  - Family Cervidae: deer
  - Family Giraffidae: Giraffe and Okapi
  - Family Antilocapridae: pronghorn
  - Family Bovidae: cattle, goats, sheep, and antelope

References
ISBN links support NWE through referral fees

Huffman, B. 2006 The Ultimate Ungulate Page Website [1]
Nowak, R.M. and Paradiso, J.L. 1983. Walker's Mammals of the World. Baltimore, Maryland, USA : The Johns Hopkins University Press
University of California Museum of Paleontology (UCMP) 2006. "Ungulates: Hoofed Mammals"[2]
Voelker, W. 1986. The Natural History of Living Mammals. Medford, New Jersey, USA : Plexus Publishing, Inc.

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@@ Line 15: / Line 15: @@
 Ungulates are typically herbivores, eating [[plant]]s; some, such as the [[pig]]s, are omnivores, eating a variety of foods including meat.
-==Relationships==
+==Perissodactyla: odd-toed ungulates==
-The [[Perissodactyla]] and [[Artiodactyla]] make up the largest portion of ungulates, and also comprise the majority of large land mammals.  These two groups first appeared during the late [[Paleocene]] and early [[Eocene]] (about 54 million years ago), rapidly spreading to a wide variety of species on numerous continents, and have developed in parallel since that time.
+{{Taxobox_begin | color = pink | name = Odd-toed ungulates}}
+{{Taxobox_image | image = [[Image:00296 zebra.jpg|240px]] | caption = [[Plains Zebra]]s}}
+{{Taxobox_begin_placement | color = pink}}
+{{Taxobox_regnum_entry | taxon = [[Animal]]ia}}
+{{Taxobox_phylum_entry | taxon = [[Chordata]]}}
+{{Taxobox_classis_entry | taxon = [[Mammal]]ia}}
+{{Taxobox_ordo_entry | taxon = '''Perissodactyla'''}}<br/>{{Taxobox authority | author = [[Richard Owen|Owen]] | date = 1848}}
+{{Taxobox_end_placement}}
+{{Taxobox_section_subdivision | color = pink | plural_taxon = Families}}
+[[Equidae]]<br />
+[[Tapiridae]]<br />
+[[Rhinocerotidae]]<br />
+[[Brontotheriidae]] [[extinction|† (extinct)]]<br />
+[[Chalicotheriidae]] †<br />
+[[Hyracodontidae]] †<br />
-Although [[whales]] and [[dolphins]] ([[Cetacea]]) do not possess most of the typical morphological characteristics of ungulates, recent discoveries have suggested that they are likely descended from early [[artiodactyls]], and thus are directly related to other [[even-toed ungulates]] such as cattle and [[hippopotami]].  As a result of these discoveries, a new order of [[Cetartiodactyla]] has also been proposed to include the members of [[Artiodactyla]] and [[Cetacea]], to reflect their common ancestry; however, strictly speaking, this is not necessary, as it is possible simply to recognize Cetacea as a subgroup of Artiodactyla.
+{{Taxobox_end}}
-The Hyracoidea, Sirenia and Proboscidea are the [[Paenungulata]]. The Tubulidentata are also thought to be ungulates. The [[Macroscelidea]] have been interpreted as ungulates, and there is dental as well as genetic evidence supporting this interpretation. The Macroscelidea and Tubulidentata have recently been united with the Paenungulata in the [[Pseudungulata]]. Genetic studies indicate that these animals are not closely related to the artiodactyls and perissodactyls. Instead, the closest relatives of pseudungulates are the [[Afrosoricida]]; the Pseudungulata and Afrosoricida make up the [[Afrotheria]].
+In the Perissodactyla, the odd-toed ungulates, the central axis of the foot passes through the third toe.
-Ungulate groups represented in the [[fossil record]] include the [[Embrithopoda|embrithopods]], [[Desmostylia|demostylians]], [[Mesonychia|mesonychids]], "[[Condylarthra|condylarths]]" and various South American and [[Palaeogene|Paleogene]] lineages.
+==Evolution==
+The odd-toed ungulates arose in what is now [[North America]] in the late [[Paleocene]], less than 10 million years after the [[dinosaur]]s died out. By the start of the [[Eocene]] (55 million years ago) they had diversified and spread out to occupy several continents. The horses and tapirs both evolved in North America; the rhinoceroses appear to have developed in [[Asia]] from tapir-like animals and then spread to the Americas during the middle Eocene (about 45 million years ago). There were 12 families, of which only three survive. These families were very diverse in form and size; they included the enormous Brontotheres and the bizarre Chalicotheres. The largest perissodactyl, an Asian rhinoceros called Paraceratherium, reached 11,000 kg (12 tons), more than twice the weight of an elephant.
-In addition to hooves, most ungulates have developed reduced [[canine teeth]], bunodont [[molar (tooth)|molars]] (molars with low, rounded cusps), and an [[astragalus]] (one of the ankle bones at the end of the lower leg) with a short, robust head.
+Perissodactyls were the dominant group of large terrestrial browsers right through the [[Oligocene]]. However, the rise of grasses in the [[Miocene]] (about 20 million years ago) saw a major change: the [[even-toed ungulate]]s with their more complex stomachs were better able to adapt to a coarse, low-nutrition diet, and soon rose to prominence. Nevertheless, many odd-toed species survived and prospered until the late [[Pleistocene]] (about 10,000 years ago) when they faced the pressure of human hunting and habitat change.
-Ungulates diversified rapidly in the [[Eocene]], but are thought to date back as far as the late [[Cretaceous]]. Most ungulates are [[herbivore]]s, but a few are [[omnivore]]s or even [[predator]]s: the [[Mesonychia]] and [[whales]].
+Today there are only 17 species of odd-toes ungulates still living and all of them are in danger of extinction except for the [[horse]] and the [[donkey]] (UCMP 2006).
-==Recent developments==
-That these groups of mammals are most closely related to each other has occasionally been questioned on anatomical and genetic grounds. Molecular [[phylogeny|phylogenetic]] studies have suggested that Perissodactyla and Cetartiodactyla are closest to [[Carnivora]] and [[Pholidota]] rather than to the Pseudungulata.
-The Pseudungulata are by some scientists united with the [[Afrosoricida]] in the cohort or super-order [[Afrotheria]] based on molecular and DNA analysis. This means they are not related to other ungulates.
+==Taxonomy==
+The members of the order fall into two suborders:
-The extinct South-American ungulates, evolved when the continent was in isolation, are united in the super-order [[Meridiungulata]]. They are by some thought to be unrelated to the other ungulates. Instead, they are united with the Afrotheria and the [[Xenarthra]] in the supercohort [[Atlantogenata]].
+*'''''Hippomorpha''''' are odd-toed ungulates that are fast runners with long legs and have only one toe; this suborder has the sole family ''Equidae'' (coextensive with the genus ''Equus''), comprising the horse, zebra, donkey, onager, and allied species.
+*'''''Ceratomorpha''''' are odd-toed ungulates that have several functional toes and are heavier than and move slower than the ''Hippomorpha'' species. This suborder has two families: Tapiridae (tapirs) and Rhinocerotidae (rhinoceroses)
-The position of other extinct ungulates is unclear. Embrithopods, Desmostylians and other related groups are seen as relatives of the Paenungulata, thus members of the Afrotheria. The condylarths are, as a result, no longer seen as the ancestors of all ungulates. Instead, it is now believed the condylarths are members of the cohort [[Laurasiatheria]]. So it seems that, of all the ungulates, only the Perissiodacyla and Artiodactyla descended from the condylarths—assuming that the animals lumped by scientists into Condylarthra over the years are even related to one another.
-As a result of all this, it seems the typical ungulate morphology originated three times independently: in the Meridiungulata, the Afrotheria and the "true" ungulates in the Laurasiatheria. This is a great example of [[convergent evolution]]. This is met with scepticism by some scientists, who say there is no morphological evidence to split the ungulates up into so many unrelated clades.
 ==Even-toed ungulates==
@@ Line 108: / Line 118: @@
 *** Family [[Bovidae]]: cattle, goats, [[sheep]], and [[antelope]]
-==Odd-toed ungulate==
-{{Taxobox_begin | color = pink | name = Odd-toed ungulates}}
-{{Taxobox_image | image = [[Image:00296 zebra.jpg|240px]] | caption = [[Plains Zebra]]s}}
-{{Taxobox_begin_placement | color = pink}}
-{{Taxobox_regnum_entry | taxon = [[Animal]]ia}}
-{{Taxobox_phylum_entry | taxon = [[Chordata]]}}
-{{Taxobox_classis_entry | taxon = [[Mammal]]ia}}
-{{Taxobox_ordo_entry | taxon = '''Perissodactyla'''}}<br/>{{Taxobox authority | author = [[Richard Owen|Owen]] | date = 1848}}
-{{Taxobox_end_placement}}
-{{Taxobox_section_subdivision | color = pink | plural_taxon = Families}}
-[[Equidae]]<br />
-[[Tapiridae]]<br />
-[[Rhinocerotidae]]<br />
-[[Brontotheriidae]] [[extinction|† (extinct)]]<br />
-[[Chalicotheriidae]] †<br />
-[[Hyracodontidae]] †<br />
-{{Taxobox_end}}
-The '''odd-toed ungulates''' are [[browsing]] and [[grazing]] [[mammal]]s that comprise the [[Order (biology)|order]] '''''Perissodactyla'''''. They are odd-[[toe]]d [[ungulate]]s (animals having an odd number of toes on the [[Hoof|hooves]]), are usually large to very large, and have relatively simple stomachs and a large middle toe.
-==Evolution==
-The odd-toed [[ungulates]] arose in what is now [[North America]] in the late [[Paleocene]], less than 10 million years after the [[Cretaceous-Tertiary extinction event]], in which the non-avian [[dinosaur]]s died out. By the start of the [[Eocene]] (55 million years ago) they had diversified and spread out to occupy several continents. The horses and tapirs both evolved in North America; the rhinoceroses appear to have developed in [[Asia]] from tapir-like animals and then reinvaded the Americas during the middle Eocene (about 45 million years ago). There were 12 families, of which only three survive. These families were very diverse in form and size; they included the enormous [[Brontotheriidae|brontotheres]] and the bizarre [[chalicothere]]s. The largest perissodactyl, an Asian rhinoceros called ''[[Paraceratherium]]'', reached 12 tons, more than twice the weight of an [[elephant]].
-Perissodactyls were the dominant group of large terrestrial browsers right through the [[Oligocene]]. However, the rise of grasses in the [[Miocene]] (about 20 million years ago) saw a major change: the [[even-toed ungulate]]s with their more complex stomachs were better able to adapt to a coarse, low-nutrition diet, and soon rose to prominence. Nevertheless, many odd-toed species survived and prospered until the late [[Pleistocene]] (about 10,000 years ago) when they faced the pressure of human hunting and habitat change.
-==Taxonomy==
-The members of the order fall into two [[suborder]]s:
-*'''''Hippomorpha''''' are odd-toed ungulates that are fast runners with long legs and have only one toe; this suborder has the sole [[Family (biology)|family]] ''[[Equidae]]'' (coextensive with the [[genus]] ''Equus''), comprising the [[horse]], [[zebra]], [[donkey]], [[onager]], and allied species.
-*'''''Ceratomorpha''''' are odd-toed ungulates that have several functional toes and are heavier than and move slower than the ''Hippomorpha'' species. This suborder has two families: [[Tapir]]idae (tapirs) and [[Rhinoceros|Rhinocerotidae]] (rhinoceroses)
-The three surviving families of odd-toed ungulate are classified as follows.
-* '''ORDER PERISSODACTYLA'''
-** '''Suborder Hippomorpha'''
-*** '''Family [[Equidae]]''': horses and allies, about 9 species in one genus
-**** [[Przewalski's horse|Przewalski's Horse]], ''Equus przewalskii''
-**** [[Horse|Domestic Horse]], ''Equus caballus'' (see also [[wild horse]])
-**** [[Donkey]] or African Ass, ''Equus asinus''
-**** [[Onager]] or Asiatic Ass, ''Equus hemionus''
-**** [[Plains Zebra]], ''Equus quagga''
-**** [[Mountain Zebra]], ''Equus zebra''
-**** [[Grevy's Zebra]], ''Equus grevyi''
-** '''Suborder Ceratomorpha'''
-*** '''Family [[Tapiridae]]''': tapirs, 4 species in one genus
-**** [[Brazilian Tapir]], ''Tapirus terrestris''
-**** [[Mountain Tapir]], ''Tapirus pinchaque''
-**** [[Baird's Tapir]], ''Tapirus bairdii''
-**** [[Malayan Tapir]], ''Tapirus indicus''
-*** '''Family [[Rhinocerotidae]]''': rhinoceroses, 5 species in 4 genera
-**** [[Black Rhinoceros]], ''Diceros bicornis''
-**** [[White Rhinoceros]], ''Ceratotherium simum''
-**** [[Indian Rhinoceros]], ''Rhinoceros unicornis''
-**** [[Javan Rhinoceros]], ''Rhinoceros sondaicus''
-**** [[Sumatran Rhinoceros]], ''Dicerorhinus sumatrensis''
 ==References==