Three families of extant mammals make up the Perissodactyla: six species of horses (Equidae), four species of tapirs (Tapiridae), and five species of rhinoceroses (Rhinocerotidae). These families are descendants of a group that flourished during the Paleogene and Neogene periods (from 65.5 million to 2.6 million years ago), when it was far more diverse in species and forms than it is today, and played a major role in the world’s fauna. Perissodactyls are significantly fewer in number than artiodactyls, and the majority of those that remain are endangered, particularly rhinoceroses, tapirs, and two of the three zebra species.
Because of their well-known fossil past, the Perissodactyla are of considerable scientific importance. The evolution of horses from the tiniest “dawn horse” (Hyracotherium, formerly Eohippus) to the current form is a well-known sequence, and understanding it has aided evolutionary theory. In addition, the arrangement is a good illustration of parallel evolution. Both perissodactyls and artiodactyls (e.g., cattle, antelope, and swine) evolved high-crowned grinding teeth and lengthened limbs with a decreased number of digits in adaptation to a comparable running (cursorial), herbivorous manner of life, but on very distinct evolutionary trajectories.
Difference Between Perissodactyla and Artiodactyla
|
Perissodactyla |
Artiodactyla |
|
Perissodactyla is one of two types of ungulates, which are mammals that walk on their toes (unguligrade locomotion). |
The Artiodactyla are ungulates with four or two toes (pigs, camels, and hippopotamuses) (deer, sheep, cattle, and their allies) |
|
Perissodactyls in the wild are medium to large in size. |
Artiodactyls were once the most common herbivores (mammals that consume plants) on nearly every continent. They are usually huge or medium-sized animals. They would compete with rabbits and larger rodents if they were any smaller. |
Odontoid Process in Perissodactyla and Artiodactyla
With only 17 species, the Perissodactyla order is quite small. Horses, donkeys, rhinoceroses, and tapirs are all included in this category (see DAIRY ANIMALS | Horse). There are six living species of Equus, including two species of ass, three species of zebra, and Przewalski’s horse, which avoided extinction in captivity and is now being reintroduced into the wild, in addition to the domestic horse and donkey.
The Perissodactyla are monophyletic, according to molecular analyses. They also defined the affiliations of hyraxes, small Middle Eastern and African animals, and validated their place in the Paenungulata, a group that also includes elephants and sirenia (sea cows and Hyraxes had previously been thought to be more morphologically diverse than other mammals, according to certain.
Tapirs (Perissodactyla: Tapiridae) used to be found all over the world, but Pleistocene glaciers forced them to seek sanctuary in Southeast Asia (particularly Sumatra) and South America. They eat a wide range of leaves and fruits, although they are picky about what they eat. They are water-dependent and frequently found in seasonally waterlogged areas, albeit they relocate to higher land during the rainy season. Tapirs are nocturnal and spend the day hiding in deep woodland.
Axis of Support in Perissodactyla and Artiodactyla
-
Perissodactyla are distinguished by their single toe (or three toes combined) sustaining the animal’s weight, with the axis of each limb going through the expanded third digit
-
Tapirs have four digits on their forefeet and three on their rear feet, while rhinos have three digits on all of their feet. In equids, the solitary third digit is the only one left
-
This is a scenario in which a runner’s specialisation is at its peak. Both Perissodactyla and Artiodactyla have functional toes that culminate in hoofs, but the foot structure differs. In contrast to artiodactyls, the median metacarpals and metatarsal bones are not united into a cannon bone
-
The proximal surface of the ankle bone (astragalus) of perissodactyls has a deep pulley-like groove that limits the movement of the animal
Conclusion
Three families of extant mammals make up the Perissodactyla: six species of horses , four species of tapirs , and five species of rhinoceroses. Perissodactyls are significantly fewer in number than artiodactyls, and the majority of those that remain are endangered, particularly rhinoceroses, tapirs, and two of the three zebra species. The evolution of horses from the tiniest “dawn horse” (Hyracotherium, formerly Eohippus) to the current form is a well-known sequence, and understanding it has aided evolutionary theory. Odontoid Process in Perissodactyla and Artiodactyla With only 17 species, the Perissodactyla order is quite small. There are six living species of Equus, including two species of ass, three species of zebra, and Przewalski’s horse, which avoided extinction in captivity and is now being reintroduced into the wild, in addition to the domestic horse and donkey. Tapirs are nocturnal and spend the day hiding in deep woodland.