Sorex roboratus Hollister 1913
Creators: name: Mittermeier, Russell A.
name: Wilson, Don E.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Soricomorpha
Soricidae
Sorex
Sorex roboratus

description: 7. Flat-skulled Shrew <i>Sorex roboratus</i> <b>French:</b> Musaraigne forte / <b>German:</b> Flachkopf-Rotzahnspitzmaus / <b>Spanish:</b> Musarana de craneo aplastado <b>Taxonomy.</b> Sorex roboratus Hollister, 1913, “Tapucha [Near Teletskoye Lake)], Altai Mountains, Siberia,” Russia. Sorex roboratus is a relict species. Sorex raddei, another relict species, is its closest relative based mtDNA. Because of their distinct placement within Sorex, both S. roboratus and S. raddei are included in the S. raddei group here. The caecutiens group is close by karyotype structure. Five subspecies recognized. <b>Subspecies and Distribution.</b> S.r.roboratusHollister,1913—Altai-Sayanregion. S.r.jakutensisDukelsky,1928—W&amp;CSiberiaandSYakutia(=SakhaRepublic). S.r.platycraniusOgnev,1921—PrimorskyKrai(SRussianFarEast). S.r.thomasiOgnev,1921—TransbaikaliaandNMongolia. S. r. vir G. M. Allen, 1914 — NE part of range (Yana, Indigirka, and Kolyma river basins). <b>Descriptive notes.</b> Head-body 58-86 mm, tail 30-48 mm, hindfoot 12-15-5 mm; weight 7-15-5 g (immatures 7-10-5 g). Tail of the Flat-skulled Shrew is 40-60% of head-body length, and injuveniles,it is covered with relatively long hairs that form distinct tuft at tip. Long and rather narrow head is a key feature; braincase is substantially less elevated than in other species of Sorex. Pelage is bicolored; light gray color of belly does not extend to sides. Back varies from light brown to dark brown among different subspecies. Juveniles and overwintering individuals are only slightly different in color. Chromosomal complement has 2n = 42 and FN = 70, with 13 pairs of metacentric and submetacentric autosomes and seven pairs of acrocentric autosomes. X-chromosome is medium-sized subtelocentric, and Y-chromosome is small subtelocentric. <b>Habitat.</b> Various habitats in different regions. In the Altai-Sayan Mountains, the Flatskulled Shrew prefers dark coniferous forests and avoids xeromorphic and open habitats. In central Yeniseitaiga,it is uncommon in forests of Yenisei high floodplains and totally absent from watershed habitats where the Common Shrew (S. araneus) is abundant. In northern Yenisei taiga and forest tundra, where the Common Shrew is absent, the Flat-skulled Shrew lives in floodplain and watershed habitats and is quite abundant but subdominant in the shrew community. In northern Yakutia, the Flat-skulled Shrew is comparatively abundant and is found even in the tundra zone. Habitats generally occupied in Yakutia are about the same as in northern Krasnoyarsk Krai; i.e. it lives in taiga watershed habitats and prefers floodplain biotopes (high and low floodplains). It should be noted that wet sedge meadows are also occupied in Yakutia and similar habitats on the Russky and Popov islands (Peter the Great Gulf, Sea ofJapan) and in the western Khentii Mountains (northern Mongolia). Anthropogenic meadows alternating with bushes are occupied in the Olekma River valley in southern Yakutia. In Primorsky Krai, Flatskulled Shrews avoid Sikhote-Alin dark coniferous—broad-leaved forests, where the Long-clawed Shrew (S. unguiculatus) is abundant and occupies forest-steppe habitats; the same habitats are preferred in Primorsky Krai and avoided in southern Siberia. Choice of habitats by the Flat-skulled Shrew is diverse probably because it avoids habitats occupied by other, ecologically similar species. <b>Food and Feeding.</b> Diets of Flatskulled Shrews differ among different regions. Earthworms are often the main component of the diet. Their occurrence in gastric contents ranges from 60% to 95%, while the second and third most common components differ among regions. Common secondary components are bugs and spiders in the central Yenisei region, coleopterans and dipterans in central and southern Yakutia, and coleopterans on the Gydan Peninsula. Diets in the eastern Sayan Mountains and Amur Region are dominated by coleopterans, followed by caterpillars. <b>Breeding.</b> Breeding of the Flat-skulled Shrew occurs in May-September, and females produce 2-3 litters/season. Male and female young-of-the-year regularly reproduce in central Yakutia, but not female young-of-the-year in the Russian Far East. Mean number of embryos/female is 9-1 in the Kolyma River drainage area, 7-4 in the Altai Mountains, 8-2 in Amur Region, four in Primorsky Krai, and 8-1 embryos/pregnant female in northern Yenisei taiga. Only one pregnant female with eleven embryos was captured in Yenisei forest-tundra. <b>Activity patterns.</b> No information. <b>Movements, Home range and Social organization.</b> No information. <b>Status and Conservation.</b> Classified as Least Concern on The IUCN Red List. The Flatskulled Shrew is on the regional Red Lists of Magadan Region and Chukotka Autonomous District. It is not abundant throughout most ofits distribution, but it is occasionally subdominant in the shrew community, as is the case in furspruce (black) taiga of Altai foothills and northern Yenisei taiga. <b>Bibliography.</b> Churchfield &amp; Sheftel (1994), Dokuchaev (1990), Dolgov (1985), Hoffmann &amp; Lunde (2008), Nesterenko (1999), Okhotina (1984), Revin (1989), Sheftel (1983, 2005), Volpert &amp; Shadrina (2002), Yudin (1962, 1989), Yudin et al. (1979), Zaitsev et al. (2014), Zima et al. (1998).
description: Published as part of <i>Russell A. Mittermeier &amp; Don E. Wilson, 2018, Soricidae, pp. 332-551 in Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona :Lynx Edicions</i> on page 397, DOI: 10.5281/zenodo.6870843