Inyo shrew

Inyo shrew
Conservation status
Least Concern  (IUCN 3.1)]
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 myops HHT Jackson, 1928

The Inyo shrew (Sorex tenellus) is a species of shrew found in the western United States. Not much is known about its behavioral and reproductive habits. It is small, very similar in appearance to the related dwarf shrew (Sorex nanus), but smaller and paler. It can be found in many different habitats, from rocky, mountainous regions to wetlands and riparian areas. While barely studied, their population is believed to be stable and not under any threat.

Taxonomy

Sorex tenellus was first described by Clinton Hart Merriam in 1895. He identified two subspecies, one of which, Sorex tenellus nanus, has since been elevated to species status as Sorex nanus. He studied three specimens of the nominate subspecies and four of S. t. nanus. The type locality, Lone Pine Creek, is located in Inyo County, California. In 1902, from specimens collected the previous summer, he identified two new subspecies — S. t. lyelli and S. t. myops. The former is now given species status as Sorex lyelli, while the latter temporarily received the same from Hartley Harrad Thompson Jackson in 1928. Later, in 1941, a study published in the Journal of Mammalogy concluded Sorex myops to simply be a synonym of S. tenellus.

It is sometimes referred to as the Great Basin dwarf shrew to distinguish it from Sorex tellenus, the dwarf shrew or Rocky Mountain dwarf shrew.

Description

The Inyo shrew is small and pale in color. Its upper regions are a light ash gray, while its lower regions 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. 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 (Serox 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. Due to its intermediate size and body mass between the larger dwarf shrew and 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.

Distribution and habitat

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. However, a specimen was recorded in 2014 in Granite Creek Canyon, Deep Creek Range, Juab County, Utah, the easternmost discovery of a Serox tenellus individual at that time, as well as the first in Utah.

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. The species has been found living in sympatry with Preble's shrew (Sorex preblei) at California's Lassen Volcanic National Park.

Behavior and ecology

Essentially nothing is known about the Inyo shrew's ecology, behavior, or reproduction, due to how little study it has received. 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.

Conservation

There are most likely well over 10,000 individuals alive today, and their population is stable. The IUCN has identified no threats and declared there to be no need to introduce new protection measures. It is found in multiple protected areas.