The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except Antarctica. Some authorities have placed all members of this group into a single family, Muridae, due to difficulties in determining how the subfamilies are related to one another. Many of the families within the Muroidea superfamily have more variations between the families than between the different clades. A possible explanation for the variations in rodents is because of the location of these rodents; these changes could have been due to radiation or the overall environment they migrated to or originated in. The following taxonomy is based on recent well-supported molecular phylogenies.
Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: Myospalax and Eospalax. Zokors are native to much of China, Kazakhstan, and Siberian Russia.
The Muridae, or murids, are either the largest or second-largest family of rodents and of mammals, containing approximately 870 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia.
Mouse-like hamsters, also called brush-tailed mice, are a group of small rodents found in Syria, Azerbaijan, Iran, Turkmenistan, Afghanistan, and Pakistan. They are found in rocky outcrops and semi-mountainous areas in desert regions.
The Spalacidae, or spalacids, are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and southeastern Europe. It includes the blind mole-rats, bamboo rats, mole-rats, and zokors. This family represents the oldest split in the muroid superfamily, and comprises animals adapted to a subterranean way of life. These rodents were thought to have evolved adaptations to living underground independently until recent genetic studies demonstrated they form a monophyletic group. Members of the Spalacidae are often placed in the family Muridae along with all other members of the Muroidea.
The rodent family Platacanthomyidae, or Oriental dormice, includes the spiny dormice and the Chinese pygmy dormice. In spite of their appearance, these animals are not true dormice, but are part of the large and complex superfamily Muroidea. The platacanthomyids can be distinguished from the true dormice, because they have no premolars, giving them three cheek teeth, like their relatives, the Muroidea.
The Nesomyidae are a family of African rodents in the large and complex superfamily Muroidea. It includes several subfamilies, all of which are native to either continental Africa or to Madagascar. Included in this family are Malagasy rodents, climbing mice, African rock mice, swamp mice, pouched rats, and the white-tailed rat.
The Eumuroida are a clade defined in 2004 by Steppan et al. that includes rats, mice and related species, though not all rodents; in other words, a specific group of muroid rodents. The clade is not defined in the standard taxonomic hierarchy, but it is between superfamily and family.
Pouched rats are a group of African rodents in the subfamily Cricetomyinae. They are members of the family Nesomyidae, which contains other African muroids such as climbing mice, Malagasy mice, and the white-tailed rat. All nesomyids are in the superfamily Muroidea, a large and complex clade containing 1⁄4 of all mammal species. Sometimes the pouched rats are placed in the family Muridae along with all other members of the superfamily Muroidea.
Spalax is a genus of rodent in the family Spalacidae, subfamily Spalacinae. It is one of two extant genera in the subfamily Spalacinae, alongside Nannospalax.
The Malagasy rodents are the sole members of the subfamily Nesomyinae. These animals are the only native rodents of Madagascar, come in many shapes and sizes, and occupy a wide variety of ecological niches. There are nesomyines that resemble gerbils, rats, mice, voles, and even rabbits. There are arboreal, terrestrial, and semi-fossorial varieties.
The Arvicolinae are a subfamily of rodents that includes the voles, lemmings, and muskrats. They are most closely related to the other subfamilies in the Cricetidae. Some authorities place the subfamily Arvicolinae in the family Muridae along with all other members of the superfamily Muroidea. Some refer to the subfamily as the Microtinae or rank the taxon as a full family, the Arvicolidae.
The Old World rats and mice, part of the subfamily Murinae in the family Muridae, comprise at least 519 species. Members of this subfamily are called murines. In terms of species richness, this subfamily is larger than all mammal families except the Cricetidae and Muridae, and is larger than all mammal orders except the bats and the remainder of the rodents.
The New World rats and mice are a group of related rodents found in North and South America. They are extremely diverse in appearance and ecology, ranging from the tiny Baiomys to the large Kunsia. They represent one of the few examples of muroid rodents in North America, and the only example of muroid rodents to have made it into South America.
The suborder Myomorpha contains 1,524 species of mouse-like rodents, nearly a quarter of all mammal species. Included are mice, rats, gerbils, hamsters, lemmings, and voles. They are grouped according to the structure of their jaws and molar teeth. They are characterized by their myomorphous zygomasseteric system, which means that both their medial and lateral masseter muscles are displaced forward, making them adept at gnawing. As in the hystricognathous rodents, the medial masseter muscle goes through the eye socket, a feature unique among mammals. Myomorphs are found worldwide in almost all land habitats. They are usually nocturnal seed-eaters.
Petromyscus is a genus of rodent in the family Nesomyidae. It is so distinct from other rodents that it is placed as the only genus in subfamily Petromyscinae. In previous classifications, Delanymys brooksi has also been placed in the subfamily. They are found in southwestern Africa. These animals have a sharp lower point to their V-shaped infraorbital canal. Their molars are intermediate between the ancestral cricetid style tooth and the dendromurine style tooth.
Otomyini is an Old World tribe of muroid rodents in the subfamily Murinae. Musser and Carleton (2005) granted it subfamily status (Otomyinae), but molecular studies consistently show that the otomyines evolved from within the Murinae, leading these researchers to subsume it in this subfamily, sometimes with tribal status. It includes 3 genera.
In anatomy, posterolateral palatal pits are gaps at the sides of the back of the bony palate, near the last molars. Posterolateral palatal pits are present, in various degrees of development, in several members of the rodent family Cricetidae. Many members of the family lack them or have only simple pits, but Arvicolinae and Oryzomyini have more highly developed posterolateral palatal pits. Posterolateral palatal pits are also present in some other rodents, including Glis, Jaculus, Hystrix, Abrocoma, Ctenomys, Chinchilla, and Lagidium.
In rodent anatomy, the zygomatic plate is a bony plate derived from the flattened front part of the zygomatic arch (cheekbone). At the back, it connects to the front (maxillary) root of the zygomatic arch, and at the top it is connected to the rest of the skull via the antorbital bridge. It is part of the maxillary bone, or upper jaw, which also contains the upper cheekteeth. Primitively, rodents have a nearly horizontal zygomatic plate. In association with specializations in zygomasseteric system, several distinct morphologies have developed across the order.
Rodents of the superfamily Muroidea, which includes mice, rats, voles, hamsters, bamboo rats, and many other species, generally have three molars in each quadrant of the jaws. A few of the oldest species retain the fourth upper premolar, and some living species have lost the third and even the second molars. Features of the molar crown are often used in muroid taxonomy, and many different systems have been proposed to name these features.
