Inyo shrew | |
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Illustration of the skull | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Eulipotyphla |
Family: | Soricidae |
Genus: | Sorex |
Species: | S. tenellus |
Binomial name | |
Sorex tenellus Merriam, 1895 | |
Inyo shrew range | |
Synonyms | |
Sorex myopsHHT Jackson, 1928 |
The Inyo shrew (Sorex tenellus) is a species of shrew found in the western United States. It is light gray and white in color, with a narrow skull and small body size, very similar in appearance to the related dwarf shrew (Sorex nanus), but paler and not as large. It can be found in many different habitats, from rocky, mountainous regions to wetlands and riparian areas. Not much is known about its behavioral and reproductive habits. While barely studied, their population is believed to be stable and not under any threat.
Sorex tenellus was first described by Clinton Hart Merriam in 1895. [2] The type locality, Lone Pine Creek, is located in Inyo County, California. [3] He identified two subspecies: Sorex tenellus tenellus (the nominate subspecies) and Sorex tenellus nanus (which has since been elevated to species status as Sorex nanus ). [2] [4] In 1902, Merriam identified two new subspecies — Sorex tenellus lyelli and Sorex tenellus myops — from specimens collected the previous summer. [5] Sorex tenellus lyelli is now given species status as Sorex lyelli , [6] while Sorex tenellus myops was also identified as a separate species by Hartley Harrad Thompson Jackson in 1928. However, in 1941, S. myops was reclassified as a synonym of S. tenellus. [7]
The Inyo shrew is sometimes referred to as the Great Basin dwarf shrew to distinguish it from Sorex nanus, which is known as the dwarf shrew or Rocky Mountain dwarf shrew. [4] Due to its intermediate size and body mass between the larger dwarf shrew and the smaller ornate shrew, as well as the potential that their ranges overlap (although this has not been observed so far), it is possible that the three form a single species. [4] Genetic studies of the genus Sorex from 2003 and 2010 have respectively identified S. tenellus as belonging to the subgenus Otisorex (along with S. hoyi , S. monticolus , S. palustris , and S. vagrans ) or outside of it, in a weakly supported clade with S. fumeus , S. oreopolus , and S. ventralis . [8] [9]
The Inyo shrew is small and pale in color. Its upperparts are a light ash gray, while its lowerparts and feet are white. The tail is bicolored, with the top darker than the white underside. Its skull is small, narrow, and extremely flat. The braincase is depressed to the rostrum and the palate is slender. [2] There is no major sexual dimorphism. In size, it ranges from 85 to 103 millimetres (3.3 to 4.1 in) long, with a tail length of 36 to 48 millimetres (1.4 to 1.9 in) and a weight of 3.4 to 4.1 grams (0.12 to 0.14 oz). Compared to the dwarf shrew (Sorex nanus), with which it was once considered conspecific, S. tenellus is slightly bigger, with a longer tail. It is also paler and grayer. Like other small shrews, it molts biannually — to its summer coat in mid-to-late July and its winter coat most likely in October. [4]
The Inyo shrew lives exclusively in the United States. According to 2016 data by the International Union for the Conservation of Nature (IUCN), they are found only in the states California and Nevada. [1] However, a specimen was recorded in 2014 in Deep Creek Range, Utah, the easternmost discovery of an Inyo shrew at that time, as well as the first in Utah. [10]
It dwells in a variety of habitats, including riparian zones, canyon bottoms, rocky and mountainous areas, and communities of red firs. They may have a relatively high tolerance for drier environments. They are usually found at altitudes above 2,300 metres (1.4 mi). While a more marginal habitat, they can also inhabit wetlands. [1] The species has been found living in sympatry with Preble's shrew (Sorex preblei) at California's Lassen Volcanic National Park. [11]
Essentially nothing is known about the Inyo shrew's ecology, behavior, or reproduction, due to how little study it has received. [4] It mainly consumes insects (possibly wind-borne insect bodies left at high altitudes), as well as other small invertebrates (such as worms, mollusks, and centipedes). It remains active the entire year. [1] In 1987, the Inyo shrew was identified as the host of a newly described species of single-celled parasite recovered from its feces, Eimeria inyoni . The parasite, of the subclass Coccidia, was noted for its thin, smooth cell wall. [12]
The IUCN classifies the Inyo shrew as being of least concern due to its stable population, its presence in multiple protected areas, and a lack of major threats to the species. The population is estimated to number well over 10,000 adults and is stable. [1]
The red-toothed shrews of the subfamily Soricinae are one of three living subfamilies of shrews, along with Crocidurinae and Myosoricinae. In addition, the family contains the extinct subfamilies Limnoecinae, Crocidosoricinae, Allosoricinae and Heterosoricinae. These species are typically found in North America, northern South America, Europe and northern Asia. The enamel of the tips of their teeth is reddish due to iron pigment. The iron deposits serve to harden the enamel and are concentrated in those parts of the teeth most subject to wear. Members of the genera Chimarrogale, Nectogale, Neomys (Nectogalini) and some members of Sorex (Soricini) are known as water shrews, due to having a semi-aquatic lifestyle.
The American pygmy shrew, also called the eastern pygmy shrew, is a small shrew found throughout much of Alaska, Canada, and the northern contiguous United States, as well as south along the Appalachian Mountains and in a small region in the Colorado and Wyoming Rockies. The species was first discovered in 1831 by naturalist William Cane in Georgian Bay, Parry Sound.
The marsh shrew, also known as the Pacific water shrew, Bendire's water shrew, Bendire's shrew and Jesus shrew is the largest North American member of the genus Sorex. Primarily covered in dark-brown fur, it is found near aquatic habitats along the Pacific coast from southern British Columbia to northern California. With air trapped in its fur for buoyancy, marsh shrews can run for three to five seconds on top of the water. It measures about 16 cm (6.3 in) in length, including a 7-centimetre (2.8 in)-long tail, and weighs an average of 14.5–16 g (0.51–0.56 oz). The marsh shrew's diet consists mainly of invertebrates, which it hunts on land and in the water. They are rare; their populations are thought to be in decline, and they are considered endangered in parts of their range.
The smoky shrew is a medium-sized North American shrew found in eastern Canada and the northeastern United States and extends further south along the Appalachian Mountains.
The genus Sorex includes many of the common shrews of Eurasia and North America, and contains at least 142 known species and subspecies. Members of this genus, known as long-tailed shrews, are the only members of the tribe Soricini of the subfamily Soricinae. They have 32 teeth.
The alpine shrew is a species of mammal in the family Soricidae. It is found in the alpine meadows and coniferous forests of central and southern European mountain ranges.
The Arizona shrew is a species of shrew native to North America.
Baird's shrew is a species of mammal in the family Soricidae. It is endemic to northwest Oregon. Baird's shrew inhabits moist conifer forests.
The Kamchatka shrew is a species of mammal in the family Soricidae. It is endemic to Russia.
The Iberian shrew or Lagranja shrew is a species of mammal in the family Soricidae. It is found in Portugal and Spain.
The Pribilof Island shrew is a small, short tailed species of mammal in the family Soricidae (shrews). It is endemic to and found only on Alaska's Pribilof Islands. Due to its distinct tricoloured coat, it was originally thought to be related to the Arctic shrew, but it is in fact much closer to the Cinereus shrew in its geographical distribution and morphological traits. Not much is known about the population size, breeding habits, ecology, and the general biology of the shrew.
The Mount Lyell shrew is a species of mammal in the family Soricidae. It is named for Mount Lyell in Yosemite National Park, the area where the shrew has been most commonly found.
The large-toothed shrew or Mexican large-toothed shrew is one of 77 species within the genus Sorex. Registered on the IUCN Red List as vulnerable with a decreasing population, the Mexican large-toothed shrew has been recorded only 14 times in seven locations. The shrew is a member of the red-toothed shrew subfamily Soricinae, and the more taxonomically defined tribe Soricini. Members of the latter category exhibit long tails relative to body size.
The dwarf shrew is a species of mammal in the family Soricidae endemic to Arizona, Colorado, Montana, Nebraska, New Mexico, South Dakota, Utah, and Wyoming in the United States. The type locality is Estes Park, Colorado, USA.
Preble's shrew is a small shrew distributed across the Great Basin of the United States and southern British Columbia in Canada.
The Sado shrew is a subspecies of mammal in the family Soricidae. It is endemic to Japan, and more specifically, the Japanese island of Sado. Although it is sometimes referred to as its own species, more recent scholarship identifies it as a subspecies of the Shinto shrew. However, there are significant morphological differences between the species.
The Shinto shrew is a species of shrew of the genus Sorex that lives only on the islands of Japan. It is a mole-like mammal with a pointed snout, very small ears, and a relatively long tail. Like most shrews, it is tiny, has poor eyesight, and a very good sense of hearing and smell which it uses to locate its prey, mainly insects.
Trowbridge's shrew is a species of mammal in the family Soricidae. It is found in southern British Columbia in Canada and in Washington, Oregon, and California in the United States.