The Shinto shrew (''Sorex shinto'') is a species of

shrew Shrews (family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to diffe ...

of the genus ''

Sorex 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 ...

'' 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. At one time, the Shinto shrew was classified as a subspecies of the ''Sorex caecutiens'', or

Laxmann's shrew Laxmann's shrew (''Sorex caecutiens''), or the masked shrew, is a species of shrew. Its range extends from northern Scandinavia and the Baltic to the Sea of Japan, including Hokkaidō, Sakhalin, and the Korean Peninsula. It favours mountain fores ...

, however as scientists collected new data on these shrews, such as

genetic testing Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

, it was decided that they should be classified as a separate species. There are three distinct populations of Shinto shrew living on the islands of Japan. Living as isolated groups on their respective islands prevents the populations from interbreeding and can allow variations to develop between the groups over time. Because of these differences, the three groups have been classified as subspecies of ''S. shinto''. Those living on

Sado Island is a city located on in Niigata Prefecture, Japan. Since 2004, the city has comprised the entire island, although not all of its total area is urbanized. Sado is the sixth largest island of Japan in area following the four main islands and O ...

are '' S. shinto sadonis'', those living on

Shikoku Island is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), ' ...

are ''S. shinto shikokensis'', and those living on Japan's main island of

Honshu , historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island ...

are ''S. shinto shinto''.

Genetics

Shinto shrew

karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ...

comprises diploid number of 42

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins ar ...

s, the same as in the case of Laxmann's shrew. A

fundamental number A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is di ...

equals to 66, as in the case of Laxmann's shrew from Hokkaido. Pairs from 1 to 9 are big metacentric or submetacentric chromosomes, and were numeratoed according to their size. Thus, the chromosome of 1st and 2nd pair are the biggest. They are metacentric and can't me discerned morfologically. A 4th pair is metacentric too. On the other side, pairs 3, 5 and 8 are submetacentric. Consecutive 9 pairs comprise telocentric chromosomes. Ones belonging to pairs from 10 to 12 are greater than others, with relatively bigger short arms. A 16th pair is submetacentric too, in contrast to telocentric pairs 17 and 19. A satellites can be found in 17th pair and, more pronounced, in 20th pair, in the end of p arm. The satellites function as active NOR. Description of chromosomes is nearly precisely the same in Long-clawed shrew, besides some local differences in the later. Authors emphasize genetic proximity of shinto and Laxmann's shrews.

X chromosome The X chromosome is one of the two sex-determining chromosomes ( allosomes) in many organisms, including mammals (the other is the Y chromosome), and is found in both males and females. It is a part of the XY sex-determination system and XO se ...

resembles a homological one of Cheju Island Laxmann's shrew according to G stripes. A kariotype observed in the shinto and Laxmann's shrews is thought to be ancestral for all Laxmann's shrew species group.

Morphology

In general appearance the shinto shrew looks similar do Laxmann's shrew, previously thought to be included in. However, it is smaller than Laxmann's shrew, but larger than

Azumi shrew The Azumi shrew (''Sorex hosonoi'') is a species of mammal in the family Soricidae. It is endemic to Japan, where it is found in the mountainous regions of central Honshu Island. It is a close relative of the Eurasian least shrew (Sorex minutis ...

. Shinto shrew head and body measure between 5.1 and 7.25 cm. Tail reaches from 4.4 to 5.7 cm, what makes its smaller than in Azumi shrew. Head length from incisors to

occipital condyles The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the atlas vertebra. The condyles are oval or reniform (kidney-shaped) in shape, and their anteri ...

is 1.65-1.81 cm. Teeth rows measures from 3.9 to 4.4 mm. Hind foot is 1.14-1.36 cm. Mass belongs to 4.1-6.2 g. Dorsum is gray-brown. Shinto shrew resembles Laxmann's shrew. Traits of the shinto shrew from

gradually comes into traits of Laxmann's shrew from

Primorsky Krai Primorsky Krai (russian: Приморский край, r=Primorsky kray, p=prʲɪˈmorskʲɪj kraj), informally known as Primorye (, ), is a federal subject (a krai) of Russia, located in the Far East region of the country and is a part of t ...

and Corea (head size) and from Sacchalin and

Hokkaido is Japan, Japan's Japanese archipelago, second largest island and comprises the largest and northernmost Prefectures of Japan, prefecture, making up its own List of regions of Japan, region. The Tsugaru Strait separates Hokkaidō from Honshu; th ...

(external measures). However, aforementioned species can be distinguished even by a surface of 4th superior premolar. Only subspecies ''S. s. sadonis'' recognizing is problematic.

Systematics

The shinto shrew was described by Oldfield Thomas in 1905, who pointed out as a type locality a village Makado (now part of small town

Noheji is a town located in Aomori Prefecture, Japan. , the town had an estimated population of 12,956, and a population density of 168 persons per km2 in 6,466 households. The total area of the town is . Geography Noheji occupies the southeastern co ...

) in

Aomori Prefecture is a prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is bordered by the Pacific Ocean to the ea ...

, northern Hondo (former name of Honsiu), Japan. However, shinto shrew was not announced as a separate species, but as a subspecies of Laxmann's shrew, a shrew species common in Asia and of wide range and numerous described subspecies. Nowadays, the shinto shrew and Laxmann's shrew are considered different species, although closely related, what was proved by genetic research. Difference between species is not evident according to some authors. Others, basing on genetical data, recognize them as separate species belonging to the same species group and of common ancestry. The group is called ''caecutiens''/''shinto'' species group. The fird species closely related to the two mentioned before is

chinese shrew The Chinese shrew or dusky shrew (''Sorex sinalis'') is a species of mammal in the family Soricidae. It is endemic to China, where it occurs in Gansu, Sichuan (including Jiuzhaigou), and Shaanxi Shaanxi (alternatively Shensi, see #Name, § ...

. The trio with

taiga shrew The taiga shrew (''Sorex isodon''), also known as the even-toothed shrew can achieve a body length of about 67 millimeters, with a tail of about 43 millimeters. This shrew is very similar to the long-clawed shrew. This species inhabits forested ...

and long-clawed shrew make caecutiens species group. It is, among few other species group and species that belongs to no species group, classified in ''Sorex Sorex'' subgenus, one of tho subgenera of genus ''

''. That genus belongs to a tribe Soricini, which, altogether with tribes Blarinini,

Blarinellini ''Blarinella'' is a small genus of shrews in the subfamily Soricinae of the family Soricidae. It contains the following three species: *Indochinese short-tailed shrew (''Blarinella griselda'') *Asiatic short-tailed shrew (''Blarinella quadrati ...

Anourosoricini Asian mole shrews (''Anourosorex'') are a genus of shrews that resemble moles, from China, Taiwan, India, and Indochina. They are the only known genus of the Anourosoricini tribe of red-toothed shrews. The four known species are:Notiosoricini i Nectogalini, creates

Soricinae The red-toothed shrews of the subfamily Soricinae are one of three living subfamilies of shrews, along with Crocidurinae (white-toothed shrews) and Myosoricinae (African white-toothed shrews). In addition, the family contains the extinct subfam ...

subfamily, one of three subfamily of Soricid family, next to

Crocidurinae The white-toothed shrews or Crocidurinae are one of three subfamilies of the shrew family Soricidae. The outer layer of these shrews' teeth is white, unlike that of the red-toothed shrews. These species are typically found in Africa and southe ...

and

Myosoricinae According to the current taxonomy, the Myosoricinae are a subfamily of shrews. As such, they form one of three main types of shrews, the other two being the red-toothed shrews and the white-toothed shrews. They are the only one of the three ...

. A cladogram according to Naitoh ''et al,''. 2005 Nowadays, 3 subspecies are enlisted: * ''Sorex shinto shinto'' Thomas, 1905; * ''Sorex shinto sadonis'' Yoshiyuki & Imaizumi, 1986; * ''Sorex shinto shikokensis'' Abe, 1967. According to some authors, ''S. shinto sadonis'' can't be genetically distinguished from a nominative subspecies and it could appear recently. Other authors point out its genetic separateness from Honsku and

Shikoku is the smallest of the four main islands of Japan. It is long and between wide. It has a population of 3.8 million (, 3.1%). It is south of Honshu and northeast of Kyushu. Shikoku's ancient names include ''Iyo-no-futana-shima'' (), ...

populations. What is more, few researched individuals don't fit former nor latter group, such ones are classified as ''S. shinto shikokensis''. Wedle niektórych autorów ''S. shinto sadonis'' jest genetycznie nieodróżnialny od podgatunku nominatywnego, być może powstały niedawno, inni wskazują na jego odrębność genetyczną od populacji zamieszkującej Honsiu i

. Ponadto nieliczne zbadane osobniki nie pasują do żadnej z tych grup, te właśnie tworzą podgatunek ''S. shinto shikokensis''. Another subspecies ''Sorex shinto chouei'' was previously described, but is seems to be a junior synonym of ''Sorex shinto shinto''. ''Sorex shinto saevus'' described by Thomas, 1907 from

Sakhalin Sakhalin ( rus, Сахали́н, r=Sakhalín, p=səxɐˈlʲin; ja, 樺太 ''Karafuto''; zh, c=, p=Kùyèdǎo, s=库页岛, t=庫頁島; Manchu: ᠰᠠᡥᠠᠯᡳᠶᠠᠨ, ''Sahaliyan''; Orok: Бугата на̄, ''Bugata nā''; Nivkh: ...

, is nowadays recognized as synonym of long-clawed shrew.

Behaviour and life cycle

Soricids usually lead a solitary life. There is no research concerning this area in the case of the shinto shrew. It lives on the ground, in the litter. Majority of caught specimens was active nightly, but in high altitude activity occurred daily. A female copulates with a male and after it she gets pregnant. Gravid females of ''Sorex shinto shinto'' subspecies were met on Honshu in May and June. Pregnant ''Sorex shinto sadonis'' females were observed from March to May. After pregnancy female gives birth to from one to six

neonate An infant or baby is the very young offspring of human beings. ''Infant'' (from the Latin word ''infans'', meaning 'unable to speak' or 'speechless') is a formal or specialised synonym for the common term ''baby''. The terms may also be used to ...

s in the case of nominatibe species and from four to six in the case of ''Sorex shinto sadonis''. A soricids usually do not live long. One generation is estimated to 1 year.

Area

THe shinto shrew is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to Japan. It lives on

(

Kii Peninsula The is the largest peninsula on the island of Honshū in Japan. It is named after the ancient Kii Province. Overview The area south of the “ Central Tectonic Line” is called , and is home to reef-like coral communities which are amongst ...

and

s. The nominative subspecies dwells in northern and central mountain areas on Honshu, on middle and high altitude. ''Sorex shinto shikokensis'' lives on Shikoku, more precisely in Ishizuchi and Tsurugi Mountains. Aforementioned Sado Island is home of ''Sorex shinto sadonis'', which is also observed on western Honshu seashore, not only in mountains, but also in lower. Shinto shrew

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s dated on

Pleistocene The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...

were found on Honshu and the ones from late Pleistocene on

Kyushu is the third-largest island of Japan's five main islands and the most southerly of the four largest islands ( i.e. excluding Okinawa). In the past, it has been known as , and . The historical regional name referred to Kyushu and its surroun ...

. The shinto shrew is sympatric with Laxmann's shrew.

Ecology

A habitats of shinto shrew are primary and secondary forests, especially coniferous, and shrubland. It could be observed in lower altitudes, even on the sea level, however, it is more frequently met in mountains, it can reach 2900 m above sea level. On the sea level it lives on Honshu, its maximum altitude on that island is 1200 m. On Shikoku it dwells from 0 do 900 m. On Sado Island it was met on 300 m above sea level. There is no specific data concerning diet of the shinto shrew. Closely related Laxmann's shrew eats

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species d ...

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

Oniscidea A woodlouse (plural woodlice) is an isopod crustacean from the polyphyleticThe current consensus is that Oniscidea is actually triphyletic suborder Oniscidea within the order Isopoda. They get their name from often being found in old wood. ...

and caterpillars. Parasites of the shinto shrew can be

nematodes The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...

, as '' Parastrongyloides winchesi'' and ''

Syphacia ''Syphacia'' is a genus of nematodes belonging to the family Oxyuridae. The genus has cosmopolitan distribution. Species: *'' Syphacia agraria'' *''Syphacia arvicolae'' *''Syphacia carlitosi'' *''Syphacia dewiae'' *''Syphacia emileromani'' ...

'', probably ''

Syphacia emileromani ''Syphacia'' is a genus of nematodes belonging to the family Oxyuridae. The genus has cosmopolitan distribution. Species: *'' Syphacia agraria'' *''Syphacia arvicolae'' *''Syphacia carlitosi'' *''Syphacia dewiae'' *'' Syphacia emileromani' ...

'', however in the latter case shrew were probably accidental hosts of mice parasite after consumption of its corpse.

Status and conservation

Population trend is table. IUCN does not give data concerning population number. Is some places the shinto shrew is abundant, like northern and central Honshu, where, as highlighted by IUCN, Izumi shrew does not occur, and Sado Island. On the other hand, on Shikoku the shinto shrew is rare and can be found only on high latitudes. It is sympatric with the Izumi shrew on Honshu. A bulk of the shinto shrew area is protected. IUCN does not mention any threats and classifies the shinto shrew as a species of least concern (LC).

References

Mammals of Japan Endemic fauna of Japan Sorex Mammals described in 1905 Taxa named by Oldfield Thomas Shrews Taxonomy articles created by Polbot {{redtoothed-shrew-stub