Arvicolinae on arvau

Wikipedia / Arvicolinae

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 (comprising the hamsters and New World rats and mice). 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 (yielding the adjective "microtine") or rank the taxon as a full family, the Arvicolidae.

The Arvicolinae are the most populous group of Rodentia in the Northern Hemisphere. They often are found in fossil occlusions of bones cached by past predators such as owls and other birds of prey. Fossils of this group are often used for biostratigraphic dating of paleontological and archeological sites in North America and Europe.

Description

The most convenient distinguishing feature of the Arvicolinae is the nature of their molar teeth, which have prismatic cusps in the shape of alternating triangles. These molars are an adaptation to a herbivorous diet in which the major food plants include a large proportion of abrasive materials such as phytoliths; the teeth get worn down by abrasion throughout the adult life of the animal and they grow continuously in compensation.

Arvicolinae are Holarctic in distribution and represent one of only a few major muroid radiations to reach the New World via Beringia. (The others are the three subfamilies of New World rats and mice.) Arvicolines do very well in the subnival zone beneath the winter snowpack, and persist throughout winter without needing to hibernate. They are also characterized by extreme fluctuations in population numbers.

Most arvicolines are small, furry, short-tailed voles or lemmings, but some, such as Ellobius and Hyperacrius, are well adapted to a fossorial lifestyle. Others, such as Ondatra, Neofiber, and Arvicola, have evolved larger body sizes and are associated with an aquatic lifestyle.

Phylogeny

The phylogeny of the Arvicolinae has been studied using morphological and molecular characters. Markers for the molecular phylogeny of arvicolines included the mitochondrial DNA cytochrome b (cyb) gene and the exon 10 of the growth hormone receptor (ghr) nuclear gene. The comparison of the cyb and ghr phylogenetic results seems to indicate nuclear genes are useful for resolving relationships of recently evolved animals. As compared to mitochondrial genes, nuclear genes display several informative sites in third codon positions that evolve rapidly enough to accumulate synapomorphies, but slow enough to avoid evolutionary noise. Of note, mitochondrial pseudogenes translocated within the nuclear genome complicate the assessment of the mitochondrial DNA orthology, but they can also be used as phylogenetic markers. Sequencing complete mitochondrial genomes of voles may help to distinguish between authentic genes and pseudogenes.

The complementary phylogenetic analysis of morphological and molecular characters suggests:

Ellobius, Prometheomys, and Lagurus are among the most basal arvicolines.
Dicrostonyx, Phenacomys, and Arborimus may form a clade.

Core arvicolines include four subclades:

Lemmini: Synaptomys, Lemmus, Myopus
Myodini: Eothenomys, Myodes
Arvicolini: Arvicola
Microtini: Alexandromys, Chionomys, Hyperacrius, Lasiopodomys, Lemmiscus, Microtus, Mictomicrotus, Neodon, Proedromys, Stenocranius, Volemys
Ondatra and Dinaromys positions are uncertain, probably compromised by the convergent evolution of morphological characters.

Some authorities have placed the zokors within the Arvicolinae, but they have been shown to be unrelated.

A 2021 study found Lemmini to be the most basal group of Arvicolinae. The study also found Arvicola to actually fall outside the tribe Arvicolini, and to be sister to the tribe Lagurini.

Classification

Subfamily Arvicolinae - voles, lemmings, muskrats

The subfamily Arvicolinae contains eleven tribes, eight of which are classified as voles, two as lemmings, and one as muskrats. Recent changes to the subfamily include disbanding genus Myodes in favor of genera Clethrionomys and Craseomys (and disbanding Myodini in favor of Clethrionomyini), moving most of the genera from Arvicolini to Microtini, and renaming Phenacomyini as Pliophenacomyini.

Tribe Arvicolini

Genus Arvicola - water voles