Belongs within: Eulipotyphla.
Contains: Soricinae, Crocidurinae, Myosorex.
The Soricidae are the shrews, the largest modern ‘family’ of lipotyphlans. The earliest definite Soricidae are recorded from the middle Eocene of North America, but with confirmed examples from Eurasia shortly thereafter and potential Eurasian species even earlier (Rose 2006). Crown group shrews are characterised by the possession of a double temporo-mandibular joint with neomorphic second lower joint surface and of a deep fossa accomodating the internal temporal muscle opening into the medial side of the coronoid process of the mandible, and the absence of the zygomatic arch, but these characters are not yet present in the stem subfamily Heterosoricinae (Butler 1988, Rose 2006).
The majority of crown-group shrews are divided between the subfamilies Soricinae and Crocidurinae, distinguished by features of the mandibular condyle and of P4 (Butler 1978). Many species of Soricinae also have the teeth pigmented red by the deposition of iron in a superficial aprismatic layer over the white enamel (Rose 2006). A third subfamily, Myosoricinae, has also been recognised for a group of African genera including the mouse shrews Myosorex. A further extinct subfamily, the Limnoecinae, is known from the Middle Miocene to Middle Pliocence of North America (Van Valen 1967). Within the Soricinae, the living tribes Soricini and Neomyini are each found in both Eurasia and the Americas. The Blarinini are present in the Recent fauna only in the Americas, but are also known from the Pliocene and Pleistocene of Eurasia. The fourth tribe, the extinct Allosoricini, are known from from the Middle Miocence to the late Pliocene of Europe (Van Valen 1967). The water shrews of the genus Neomys hunt aquatic prey, and are found in temperate Eurasia.
Meet the shrews
Published 17 May 2010
Assuming, of course, that you haven’t already met. The Soricidae are a family of small insectivorous mammals found throughout Eurasia, Africa and North America, with a small number of species extending to South America. By mammal standards, this is a fairly large family with about 370 species currently recognised and a small but steady trickle of new species still being published such as Sylvisorex akaibei from the Congo within the past year (Mukinzi et al., 2009).
Living shrews are usually divided between two subfamilies, the Soricinae and the Crocidurinae, or the red-toothed shrews and white-toothed shrews respectively (Dubey et al 2007). Red-toothed shrews, found in Eurasia and the Americas, are named after one of their most unusual features, red crowns to their teeth due to the deposition of iron in their enamel (this feature has been lost in a few soricine genera). White-toothed shrews are found in Africa and tropical Asia and make up for lacking the funky tooth pigment of Soricinae by including such creatures as the insanely over-developed hero shrew Scutisorex somereni and the bewildering diversity of the genus Crocidura with in excess of 150 species. Other notable features of shrews include the production by at least some species of toxic saliva, and the formation by young shrews of ‘caravans’. One youngster will grasp its mother’s rump in its mouth, its own rump will be grabbed by another, and so on until the entire brood forms a train by which the mother will lead it about. The young shrews will remain determinedly clinging to each other even picked up and dangled above the ground like a living monkey chain (Nowak 1999).
Most shrews are terrestrial generalists though a number of species are semi-aquatic, particularly in the soricine tribe Nectogalini. The American and Pacific water shrews, Sorex palustris and S. bendirii, are capable of running short distances across the surface of water due to their small size and hairy feet. The little-known central African Ruwenzorisorex suncoides has large premolars that have been suggested to indicate a diet of molluscs. In contrast, the mole shrews of the genus Anourosorex are (funnily enough) mole-like burrowers feeding on burrowing insects and earthworms.
Systematics of Soricidae
Characters (from Rose 2006): Mandible with long, pointed angular process; auditory bulla and zygomatic arch absent. Enlarged anterior incisors, lower incisor procumbent and often with serrated or multilobed crown; remaining antemolar teeth reduced; P4 primitively unicuspid and triangular; P4/M1 shear developed; dilambdodont molars. Entoconid usually large and separate from hypolophid.
<==Soricidae | i. s.: Arctisorex polarisTH03 | Mafia Reumer 1984P04 | `--M. csarnotensis Reumer 1984P04 | LimnoecinaeV67 | |--Angustidens Repenning 1967V67 | `--Limnoecus Stirton 1930V67 | Podihik Deraniyagala 1958V67 | SoricolestesR06 |--+--SoricinaeB78 | `--+--CrocidurinaeB78 | `--+--MyosorexMJ11 | `--+--Surdisorex Thomas 1906FS15, V67 | | |--S. norae Thomas 1906 [=Myosorex (Surdisorex) norae]AS86 | | `--S. polulus Hollister 1916 [=Myosorex (Surdisorex) polulus]AS86 | `--Congosorex Heim de Balsac & Lamotte 1956FS15, V67 | |--C. verheyeniFS15 | `--+--C. phillipsorumFS15 | `--C. polliFS15 [=Myosorex polliBP87] `--HeterosoricinaeB88 |--Paradomina Hutchison 1966V67 |--Ingentisorex Hutchison 1966V67 |--Trimylus Roger 1885 [incl. Heterosorex Gaillard 1915]V67 |--QuercysorexR06 `--Domnina Cope 1873 [incl. Miothen Cope 1873, Protosorex Scott 1895]V67 |--*D. gradata Cope 1873M60 |--‘*Miothen’ crassigenus Cope 1873M60 |--‘Protosorex’ crassusM60 |--D. dakotensisTS96 |--‘Miothen’ gracile Cope 1873M60 |--D. greeniTS96 |--D. sagittariensisHUG17 `--D. thompsoni Simpson 1941M58
*Type species of generic name indicated
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