| 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 | |
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| Inyo shrew range | |
| Synonyms | |
Sorex myopsHHT Jackson, 1928 | |
TheInyo shrew (Sorex tenellus) is a species ofshrew found in the westernUnited States. It is light gray and white in color, with a narrow skull and small body size, very similar in appearance to the relateddwarf shrew (Sorex nanus), but paler and not as large. It can be found in many different habitats, from rocky, mountainous regions to wetlands andriparian 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 byClinton Hart Merriam in 1895.[2] The type locality,Lone Pine Creek, is located inInyo County, California.[3] He identified twosubspecies:Sorex tenellus tenellus (thenominate subspecies) andSorex tenellus nanus (which has since been elevated to species status asSorex nanus).[2][4] In 1902, Merriam identified two new subspecies —Sorex tenellus lyelli andSorex tenellus myops — from specimens collected the previous summer.[5]Sorex tenellus lyelli is now given species status asSorex lyelli,[6] whileSorex tenellus myops was also identified as a separate species byHartley Harrad Thompson Jackson in 1928. However, in 1941,S. myops was reclassified as a synonym ofS. tenellus.[7]
The Inyo shrew is sometimes referred to as the Great Basin dwarf shrew to distinguish it fromSorex 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 smallerornate 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 genusSorex from 2003 and 2010 have respectively identifiedS. tenellus as belonging to thesubgenusOtisorex (along withS. hoyi,S. monticolus,S. palustris, andS. vagrans) or outside of it, in a weakly supportedclade withS. fumeus,S. oreopolus, andS. ventralis.[8][9]
The Inyo shrew is small and pale in color. Its upperparts are a lightash 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. Thebraincase is depressed to therostrum and thepalate is slender.[2] There is no majorsexual 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 consideredconspecific,S. tenellus is slightly bigger, with a longer tail. It is also paler and grayer. Like other small shrews, itmolts 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 theUnited States. According to 2016 data by theInternational Union for the Conservation of Nature (IUCN), they are found only in the statesCalifornia andNevada.[1] However, a specimen was recorded in 2014 inDeep 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, includingriparian zones, canyon bottoms, rocky and mountainous areas, and communities ofred 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 inhabitwetlands.[1] The species has been found living insympatry withPreble's shrew (Sorex preblei) at California'sLassen 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 consumesinsects (possibly wind-borne insect bodies left at high altitudes), as well as other smallinvertebrates (such asworms,mollusks, andcentipedes). 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 itsfeces,Eimeria inyoni. The parasite, of the subclassCoccidia, was noted for its thin, smoothcell 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]
