Eutamias is a genus of chipmunks within the tribe Marmotini of the squirrel family. It includes a single living species, the Siberian chipmunk. The genus is often treated as a subgenus of Tamias, which is now restricted to the eastern chipmunk of North America. Neotamias, which now includes the western North American chipmunks, has also been included in Eutamias.
Simplicidentata is a group of mammals that includes the rodents and their closest extinct relatives. The term has historically been used as an alternative to Rodentia, contrasting the rodents with their close relatives the lagomorphs. However, Simplicidentata is now defined as including all members of Glires that share a more recent common ancestor with living rodents than with living lagomorphs. Thus, Simplicidentata is a total group that is more inclusive than Rodentia, a crown group that includes all living rodents, their last common ancestor, and all its descendants. Under this definition, the loss of the second pair of upper incisors is a synapomorphic feature of Simplicidentata. The loss of the second upper premolar (P2) has also been considered as synapomorphic for Simplicidentata, but the primitive simplicidentate Sinomylus does have a P2.
The Bahia porcupine, Coendou insidiosus, is a New World porcupine species in the family Erethizontidae endemic to the Atlantic Forest of southeastern Brazil. It was formerly sometimes assigned to Sphiggurus, a genus no longer recognized since genetic studies showed it to be polyphyletic. Sphiggurus pallidus, formerly considered a separate species but known from two young specimens only, is a synonym of this species.
Roosmalen's dwarf porcupine, Coendou roosmalenorum, is a porcupine species from the New World porcupine family likely endemic to northern Brazil. Only three specimens were known at the time, and only one had a collection locality. It is named for Marc van Roosmalen and his son Tomas, whose collections from the middle Madeira included the first known specimens. It was soon assigned to the genus Sphiggurus, although this genus was not recognized by the authors. Genetic studies in 2013 have since showed Sphiggurus to be polyphyletic. Nonetheless it is commonly classified as Sphiggurus roosmalenorum. Coendou roosmalenorum may be misspelled due to a conflicting basionym combination.
Steneofiber is an extinct genus of beavers from Eurasia.
Roberto's spiny-rat, Proechimys roberti, or Para spiny rat, is a spiny rat species from South America. It is found in Brazil.
The gray leaf-eared mouse is a rodent species from South America. It is found in Argentina, Bolivia, Brazil and Paraguay; its habitat includes the Gran Chaco.
Eurymylidae is a family of extinct simplicidentates. Most authorities consider them to be basal to all modern rodents and may have been the ancestral stock whence the most recent common ancestor of all modern rodents arose. However, the more completely known eurymylids, including Eurymylus, Heomys, Matutinia, and Rhombomylus, appear to represent a monophyletic side branch not directly ancestral to rodents. Huang et al. (2004) have argued that Hanomys, Matutinia, and Rhombomylus form a clade characterized by distinctive features of the skull and dentition that should be recognized as a separate family, Rhombomylidae. Eurymylids are only known from Asia.
Armintomys is an extinct genus of rodent from North America related to jerboas and jumping mice. It is the only genus in the family Armintomyidae. It lived during the early Eocene, and is the oldest known example of a hystricomorphous zygomasseteric dentition. In addition, Armintomys is also the oldest known rodent that had an incisor enamel transition from pauciserial to uniserial. Its remains have only been found in the Wind River Basin in Wyoming, and could be found there during the species' existence on Earth. It was previously assumed that Armintomys belonged to the Dipodoidea family, but has since been understood to have been part of an early radiation of dipodoid rodents, but was not directly ancestral to any later dipodoids, thus it was recategorized into its own family.
Vesper mice are rodents belonging to a genus Calomys. They are widely distributed in South America. Some species are notable as the vectors of Argentinian hemorrhagic fever and Bolivian hemorrhagic fever.
The Tsaganomyidae are an extinct family of rodents from Asia. It contains three genera. Tsaganomyids are generally considered to be related to the Hystricognathi. Members of Tsaganomyidae were fossorial (digging) rodents that probably used their incisor teeth to dig like some living mole rats.
Isthmomys is a genus of rodent in the family Cricetidae, belonging to the tribe Reithrodontomyini. Species are:
Propalaeocastor is a poorly known extinct genus of beavers from the early Oligocene of Europe and Asia. Recently described material of a new species of Propalaeocastor, P. irtyshensis, indicates the genus is probably the earliest known member of the subfamily Castorinae, which includes all castorids more closely related to living beavers than to the extinct giant beaver. Previously, Propalaeocastor had been allied with more basal beavers such as Agnotocastor and Anchitheriomys. According to Wu and coauthors, Propalaeocastor, specifically P. butselensis, is the likely ancestor of the better-known Eurasian castorine Steneofiber.
Aegialomys is a genus of oryzomyine rodents from the lowlands and mountains of western Peru and Ecuador, including the Galápagos Islands. The species in this genus have historically been placed in Oryzomys, but according to cladistic research, the genus is more closely related to a group containing, among others, Nectomys and Sigmodontomys, than to Oryzomys. The generic name Aegialomys means "coastal mouse" in Ancient Greek and references the mostly coastal occurrence of the genus.
Cerradomys scotti, also known as Lindbergh's oryzomys, is a rodent species from South America in the genus Cerradomys. It is terrestrial and is found in the cerrado (savanna) ecozone of south central Brazil, Bolivia and Paraguay. The species is common and appears to tolerate a degree of agricultural habitat modification.
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.
Saxatilomys paulinae is a species of murid rodent native to central Laos and Vietnam, separated to a monotypic genus Saxatilomys. It was first discovered in the Khammouan Limestone National Biodiversity Conservation Area in Khammouan Province, Laos, and also been found in the Vietnamese province of Quang Bình. It is the only known species in the genus Saxatilomys. The genus name is derived from the Latin saxatilis, meaning "among the rocks" and the Greek mys, meaning mouse or rat.
Louise H. Emmons is an American zoologist who studies tropical rainforest mammals, especially rodents. She has conducted fieldwork in Gabon, Sabah (Borneo), Peru, and Bolivia. Her best known work is the field guide, Neotropical Rainforest Mammals: A Field Guide, first published in 1990, with a second edition in 1997.
Polymorphis is an extinct genus of litopterns belonging to the family Macraucheniidae. It lived during the Middle Eocene of Argentina.
