The thin mouse shrew (''Myosorex tenuis'') is a species of

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

in the family Soricidae found in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

Taxonomy

''Myosorex tenuis'' was first described by Thomas and Schwann in 1905, and was often considered a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

or subspecies of ''M. cafer.'' It is not accepted by all taxonomic analyses, partly due to a lack of accessible definitively identified specimens. Taylor et al., in a 2013 paper, provisionally identified a newly described species of ''Myosorex'' with the previously described species ''M. tenuis'', but the identification is uncertain. Their identification was based primarily on genetic data.

Description

''Myosorex tenuis'' is a medium-sized shrew with dark fur. It is sometimes distinguished from other species of the genus by a smaller skull size, but species in this genus are typically difficult to morphologically identify due to significant intra-species variation. It is primarily separated from the similar ''M. cafer'' by genetic differences and habitat, and is estimated by Taylor et al to have diverged from its nearest genetic relative, ''M. varius'', approximately 2.7 million years ago. A 2023 climatic niche modelling study proposes that the divergence from ''M. varius'' was due to habitat contraction during a

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

cycle; the divergence roughly coincided with the start of the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

glacial cycles. The species habitat is

Afromontane The Afromontane regions are subregions of the Afrotropical realm, one of the Earth's eight biogeographic realms, covering the plant and animal species found in the mountains of Africa and the southern Arabian Peninsula. The Afromontane regions o ...

grassland, and they are more common at higher elevations. Specimens have primarily been collected from wetlands and moist grassland. The species was originally identified in Wakkerstroom District,

Mpumalanga Province Mpumalanga () is one of the nine provinces of South Africa. The name means "East", or literally "The Place Where the Sun Rises" in the Nguni languages. Mpumalanga lies in eastern South Africa, bordering Eswatini and Mozambique. It shares bor ...

, South Africa, while the species identified by Taylor et al provisionally identified with ''M. tenuis'' is found in

Limpopo Province Limpopo () is the northernmost province of South Africa. It is named after the Limpopo River, which forms the province's western and northern borders. The term Limpopo is derived from Rivombo (Livombo/Lebombo), a group of Tsonga settlers ...

, South Africa. The species range may reach

Eswatini Eswatini, formally the Kingdom of Eswatini, also known by its former official names Swaziland and the Kingdom of Swaziland, is a landlocked country in Southern Africa. It is bordered by South Africa on all sides except the northeast, where i ...

and

Mozambique Mozambique, officially the Republic of Mozambique, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Afr ...

. Due to its limited range and the loss and fragmentation of grassland habitat, the species is considered endangered, though there is no clear estimate of its population numbers. Modelling by Taylor et al. estimates a 35–41% decrease in their habitat from 1975 to 2050; threats include mining, overgrazing, and expansion of human settlement in the region.

References

External links

{{Taxonbar, from=Q1765973 Endemic fauna of South Africa Myosorex Mammals of South Africa Taxonomy articles created by Polbot Mammals described in 1905 Taxa named by Oldfield Thomas