Abrotrichini

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Abrotrichini
Temporal range: Pliocene to Recent [1]
Abrothrix sanborni.jpg
Abrothrix sanborni
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Cricetidae
Subfamily: Sigmodontinae
Tribe: Abrotrichini
D'Elía, Pardiñas, Teta, and Patton, 2007
Type genus
Abrothrix
Waterhouse, 1837 [1]
Genera [1]

Abrotrichini, also known as the Andean clade [2] or southern Andean clade, [3] is a tribe of rodents in the subfamily Sigmodontinae. [1] It includes about fifteen species in four genera, [4] distributed in South America from southern Peru to southernmost South America, including the Patagonian steppes. The earliest known fossils are from the Pliocene of Argentina. [1]

Contents

Taxonomy

Abrotrichines were universally placed in the tribe Akodontini until the 1990s, and some were even classified within the genus Akodon . Allozyme studies in the early 1990s first provided evidence for their distinction from Akodontini, [1] and in 1999 a study analyzing sequences of the mitochondrial cytochrome b gene found further evidence for the distinction between Akodontini and this group and proposed the name Abrotrichini for the latter. [5] The name Abrotrichini remained formally unavailable under the International Code of Zoological Nomenclature, however, because their proposal had been conditional. [6] Thus, the clade remained without a valid name and for this reason it was included in Akodontini in the 2005 third edition of Mammal Species of the World . [3] Other phylogenetic studies, which also incorporated nuclear genes, affirmed the distinction between Akodontini and the new group. [7] In 2007, Guillermo D'Elía and coworkers published a full diagnosis of the tribe Abrotrichini, validating the name. [1]

Abrotrichini includes four genera— Abrothrix , Chelemys , Geoxus , and Notiomys —which fall into two major subgroups, one including only Abrothrix and one including the four other genera. [8] Abrothrix has formerly been included in Akodon and includes about nine species, among which are the northernmost abrotrichine, Abrothrix jelskii as well as far southern forms such as Abrothrix lanosus . [9] Within the remaining group, Chelemys is sister to the remaining genera; [8] it includes three species found in central and southern Chile and nearby Argentina. [10] The remaining three genera, each of which includes a single species, are closely related and share fossorial (digging) habits. [8] Geoxus occurs in central and southern Chile and nearby Argentina, [11] and Notiomys in southern Argentina, [12]

The tribe is part of the clade Oryzomyalia, which includes most of the subfamily Sigmodontinae. [13] Within Oryzomyalia, some studies have recovered Wiedomys as the closest relative of Abrotrichini, [14] but the basal relationships among the components of Oryzomyalia remain elusive. [15] Sigmodontinae encompasses hundreds of species found throughout South America and into North America. It is one of several subfamilies recognized in the family Cricetidae, which includes many more species, mainly from Eurasia and North America. [4]

Description

Abrotrichines are small to medium-sized sigmodontine rodents with long and soft, [1] usually gray or brown [8] fur, a short, hairy tail and large, strong feet with well-developed claws. In the skull, the snout is long, the interorbital region hourglass-shaped, and the braincase rounded. The palate is long (extending back beyond the third molars). There are no grooves in the upper incisors and the molars are not hypsodont (high-crowned). The molars lack many accessory features, in particularly the third upper molar. There are 13 thoracic (chest) vertebrae with associated ribs, 6 lumbar vertebrae, and 18 to 29 caudal (tail) vertebrae. [1]

A karyotype of 52 chromosomes (2n = 52), present in several species, has been suggested as a synapomorphy of the tribe, [16] but while this possibility is yet to be tested, Pearsonomys is now known to have 2n = 56 and some Abrothrix olivaceus have 2n = 44. [8]

Related Research Articles

<span class="mw-page-title-main">Muroidea</span> Superfamily of rodents

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.

<span class="mw-page-title-main">Akodontini</span> Tribe of rodents

Akodontini is the second most speciose rodent tribe of the subfamily Sigmodontinae. It includes at least 106 living species in 19 genera and is distributed mainly in the southern half of South America, with only two genera extending into Guyana (Podoxymys) and Venezuela (Necromys). It also includes genera previously placed in tribe Scapteromyini. The following genera are now generally recognized:

<span class="mw-page-title-main">New World rats and mice</span> Rodents native to the Americas

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 in 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.

<i>Akodon</i> Genus of rodents

Akodon is a genus consisting of South American grass mice. They mostly occur south of the Amazon Basin and along the Andes north to Venezuela, but are absent from much of the basin itself, the far south of the continent, and the lowlands west of the Andes. Akodon is one of the most species-rich genera of Neotropical rodents. Species of Akodon are known to inhabit a variety of habitats from tropical and tropical moist forests to altiplano and desert. Fossils are known from the late Pliocene onwards.

Bibimys is a genus of new world rats. Commonly known as the crimson-nosed rats, there are three species:

<i>Euryoryzomys emmonsae</i> Amazonian rodent

Euryoryzomys emmonsae, also known as Emmons' rice rat or Emmons' oryzomys, is a rodent from the Amazon rainforest of Brazil in the genus Euryoryzomys of the family Cricetidae. Initially misidentified as E. macconnelli or E. nitidus, it was formally described in 1998. A rainforest species, it may be scansorial, climbing but also spending time on the ground. It lives only in a limited area south of the Amazon River in the state of Pará, a distribution that is apparently unique among the muroid rodents of the region.

<i>Oligoryzomys</i> Genus of rodents

Oligoryzomys is a genus of rodents in the tribe Oryzomyini of family Cricetidae. Many species are known as pygmy rice rats or colilargos. The genus is found from Mexico to Tierra del Fuego and includes approximately 17 species.

Abrothrix olivaceus markhami, also known as the Wellington Akodont or Markham's Grass Mouse, is a subspecies of the South American rodent Abrothrix olivaceus. It occurs on Wellington Island and the nearby Southern Patagonian Ice Field in southern Chile. It was previously recognized as a valid species, but is close to other recognized subspecies of A. olivaceus.

Abrothrix olivacea, also known as the olive grass mouse or olive akodont, is a species of rodent in the genus Abrothrix of family Cricetidae. It is found from northern Chile into southern Chile and Argentina, including the islands of Tierra del Fuego. It is prone to large swings in population size.

<i>Akodon spegazzinii</i> Rodent in the family Cricetidae found in northwestern Argentina

Akodon spegazzinii, also known as Spegazzini's akodont or Spegazzini's grass mouse, is a rodent in the genus Akodon found in northwestern Argentina. It occurs in grassland and forest at 400 to 3,500 m above sea level. After the species was first named in 1897, several other names were given to various populations now included in A. spegazzinii. They are now all recognized as part of a single, widespread and variable species. Akodon spegazzinii is related to Akodon boliviensis and other members of the A. boliviensis species group. It reproduces year-round. Because it is widely distributed and common, Akodon spegazzinii is listed as "least concern" on the IUCN Red List.

<i>Abrothrix</i> Genus of rodents

Abrothrix is a genus of rodent in the tribe Abrotrichini of family Cricetidae. It contains the following living species:

Irenomys tarsalis, also known as the Chilean climbing mouse, Chilean tree mouse, or long-footed irenomys, is a rodent found in Chile, from about 36° to 46°S, and in adjacent Argentina, mainly in forests. It is a large, long-tailed, soft-furred mouse characterized by grooved upper incisors and specialized molars with transverse ridges, divided by deep valleys, which are connected by a transverse ridge along the midline of the molars.

<i>Eremoryzomys</i> Rodent species in the family Cricetidae from central Peru

Eremoryzomys polius, also known as the gray rice rat or the Marañon oryzomys, is a rodent species in the tribe Oryzomyini of the family Cricetidae. Discovered in 1912 and first described in 1913 by Wilfred Osgood, it was originally placed in Oryzomys and named Oryzomys polius. In 2006, a cladistic analysis found that it was not closely related to Oryzomys in the strict sense or to any other oryzomyine then known, so that it is now placed in its own genus, Eremoryzomys. The Brazilian genus Drymoreomys, named in 2011, is probably the closest relative of Eremoryzomys. Eremoryzomys has a limited distribution in the dry upper valley of the Marañón River in central Peru, but may yet contain more than one species.

<span class="mw-page-title-main">Oryzomyini</span> Tribe of rodents

Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera, distributed from the eastern United States to the southernmost parts of South America, including many offshore islands. It is part of the clade Oryzomyalia, which includes most of the South American Sigmodontinae.

Geoxus annectens, also known as Pearson's long-clawed akodont or Pearson's long-clawed mouse, is a species of rodent in the tribe Abrotrichini of family Cricetidae. Molecular data suggests that its closest relative is Geoxus valdivianus. Formerly classified in its own genus, Pearsonomys, named after American zoologist Oliver Payne Pearson, it was moved to Geoxus in 2016 after a morphological and genetic reevaluation of the tribe Abrotrichini. This rodent is endemic to Chile, where it is found in Nothofagus forest of the Valdivian temperate rainforest ecoregion.

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.

<span class="mw-page-title-main">Zygomatic plate</span> Bony plate in rodent anatomy

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.

In mammals, ungual tufts are tufts of hairs at the base of claws of the forefeet and hindfeet. Their presence has been used as a character in cladistic studies of the Cricetidae, a large family of rodents.

<i>Agathaeromys</i> Extinct genus of rodents

Agathaeromys is an extinct genus of oryzomyine rodents from the Pleistocene of Bonaire, Netherlands Antilles. Two species are known, which differ in size and some details of tooth morphology. The larger A. donovani, the type species, is known from hundreds of teeth that are probably 900,000 to 540,000 years old, found in four localities. A. praeuniversitatis, the smaller species, is known from 35 teeth found in a single fossil site, which is probably 540,000 to 230,000 years old.

Rhagomys is a genus of South American rodents in the tribe Thomasomyini of the family Cricetidae. Two species separated by about 3100 km are known, from southeast Peru and Bolivia east of the Andes, and in the Atlantic Forest of southeast Brazil. An undetermined species of Rhagomys has also been reported from Mato Grosso in central Brazil. The species are as follows:

References

  1. 1 2 3 4 5 6 7 8 9 D'Elía et al., 2007, p. 188
  2. ↑ Smith and Patton, 1999, p. 104
  3. 1 2 Musser and Carleton, 2005, p. 1087
  4. 1 2 Musser and Carleton, 2005
  5. ↑ Smith and Patton, 1999, p. 106
  6. ↑ Smith and Patton, 1999, p. 106: "An appropriate name for the new tribe would be Abrotrichini"; D'Elía et al., 2007, p. 190
  7. ↑ D'Elía, 2003, fig. 1; D'Elía et al., 2003, fig. 2; D'Elía et al., 2006, figs. 1, 2
  8. 1 2 3 4 5 D'Elía et al., 2007, p. 190
  9. ↑ Musser and Carleton, 2005, pp. 1088–1091
  10. ↑ Musser and Carleton, 2005, pp. 1109–1110
  11. ↑ Musser and Carleton, 2005, p. 1116
  12. ↑ Musser and Carleton, 2005, p. 1136
  13. ↑ D'Elía et al., 2006, fig. 1
  14. ↑ Smith and Patton, 1999, figs. 4, 5; D'Elía et al., 2006, fig. 1
  15. ↑ D'Elía et al., 2006, p. 563
  16. ↑ Smith and Patton, 1999, p. 105

Literature cited

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