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Another difference between the two orders is that many artiodactyls (except for Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine (as perissodactyls do). Molecular biology, along with new fossil discoveries, has found that cetaceans ( whales , dolphins , and porpoises ) fall within this taxonomic ...
The two extant orders of ungulates are the Perissodactyla (odd-toed ungulates) and Artiodactyla (even-toed ungulates). Hyracoidea (hyraxes) , Sirenia (sea cows, dugongs and manatees) and Proboscidea (elephants) were in the past grouped within the clade "Ungulata", later found to be a polyphyletic and now invalid clade.
The order Artiodactyla consists of 349 extant species belonging to 132 genera. This does not include hybrid species or extinct prehistoric species. Modern molecular studies indicate that the 132 genera can be grouped into 23 families; these families are grouped into named suborders and many are further grouped into named clades, and some of these families are subdivided into named subfamilies.
Panperissodactyla ("all perissodactyls", alternatively spelled Pan-Perissodactyla [2]) is a clade of ungulates containing living order Perissodactyla (odd-toed ungulates) and all extinct ungulates more closely related to Perissodactyla than to Artiodactyla (even-toed ungulates). [1]
Perissodactyla is an order of placental mammals composed of odd-toed ungulates – hooved animals which bear weight on one or three of their five toes with the other toes either present, absent, vestigial, or pointing backwards.
Laurasiatheria (/ l ɔː r ˌ eɪ ʒ ə ˈ θ ɪər i ə,-θ ɛr i ə /; "Laurasian beasts") is a superorder of placental mammals that groups together true insectivores (eulipotyphlans), bats (chiropterans), carnivorans, pangolins (), even-toed ungulates (artiodactyls), odd-toed ungulates (perissodactyls), and all their extinct relatives.
Three or four cheek teeth are present on each jaw half, so the dental formula of odd-toed ungulates is: 0-3 . 0-1 . 2-4 . 3 1-3 . 1 . 2-4 . 3 × 2 = 30-44. The guttural pouch, a small outpocketing of the auditory tube that drains the middle ear, is a characteristic feature of Perissodactyla. [10]
The traditional Ferungulata was established by George Gaylord Simpson in 1945. [1] It grouped together the extant orders Carnivora, Perissodactyla and Artiodactyla with the Tubulidentata and the superorder Paenungulata, as well as a number of orders known only from fossils.