Palæos:		Unit 460: Insectivora
The Vertebrates		700 Soricidae

Insectivora: Soricidae

Shrews

EUTHERIA
|--Insectivora
|  |--Chrysochloroidea
|  `--+--Erinaceomorpha 
|     `--Soricomorpha
|        |--Tenrecoidea
|        `--+--Solenodontidae
|           `--+--Talpoidea
|              `--Soricoidea
|                 |--Apternodontidae
|                 `--Soricidae  
|                    |--Crocidurinae
|                    `--Soricinae
`--+--+--ANAGALIDA 
   |  `--ARCHONTA
   `--+--FERAE
      `--UNGULATOMORPHA  

Taxa on This Page

1. Crocidurinae
2. Soricidae
3. Soricoidea

Soricidae: (extant shrews: > 20 genera)

Range: possibly from the Late Cretaceous.  Certainly from the Late Eocene; cosmopolitan except for Australia, Antarctica, and southern South America. 

Phylogeny: Soricoidea:::: Parapternodontidae + *: Crocidurinae + Soricinae.

Characters: head + body 3.5-18 cm [N99]; most very small, 2.5-180 g [V+00] (compare [N99]: 2-35 g, usually ≤ 18g); skull long, narrow [N99] & usually dorsoventrally flattened [V+00]; snout long & thin [V+00]; eyes tiny [V+00] and vision poorly developed [N99]; zygomatic arch absent [V+00]; postorbital process absent; pinnae sometimes conspicuous [N99] [V+00]; auditory bulla absent [V+00]; tympanic distinctively annular [V+00]; brain small, with smooth cerebra [N99]; dentary with well-developed double condyle, with non-articulating strip separating upper & lower condyles [MN93] [3]; diphyodont, with 1st set lost embryonically [N99]; dental formula 3/1-2, 1/0-1, 1-3/1, 3/3; I1 enlarged, with hooked end & with 1 cusp projecting ventrally at the base [N99]; i1 large with elongate, forward-projecting main cusp & well-separated smaller, distal secondary cusp; distal incisors, canines, & premolars small & peg-like; upper molars dilambdodont, with a strongly developed W-shaped ectoloph [N99]; M1 without mesially projecting parastyle [A+02$]; M1-2 with prominent buccodistal metacone [A+02$]; M1-2 with prominent linguodistal hypocone [A+02$]; lower molars with well-defined talonid basin [A+02$]; limbs short [N99]; digits 5/5 and usually unspecialized [N99] [V+00] [2]; plantigrade [V+00]; tibia & fibula fused [N99]; pelage dense [N99]; main  senses are probably touch, hearing, and smell; some species with toxic saliva and i1 medial surface concave, associated with salivary ducts, for injection [V+00]; very high metabolic rate and highest oxygen content and heart rate in mammals [V+00] (compare [N99]: expressing doubt); common urogenital opening in most species. [N99]; rudimentary echolocation in some species [V+00]; notably solitary except during breeding season (one exception: Cryptotis parva) [N99]; high mortality from shock (handling, loud noises, change of environment, even thunder) [N99]; usually in moist environments (some exceptions) & some with frankly aquatic adaptations [N99] [V+00]. 

Notes: [1] this is a huge group, with over 20 extant genera and 300 species, to which we will one day have to devote an entire unit.  [2] only one species has webbed feet.  Most aquatic shrews have long hairs around the toes.  These increase the surface area and trap air bubbles, allowing limited walking on the surface of still water. [N99].  [3] according to [MN93], the upper condyle is the original temporomandibular joint and is separated in life from the squamosal by a inter-articular disk. The lower joint is a simpler synovial joint without a disk.  This "is accompanied by drastic functional rearrangement of the" jaw adductors, including loss of the deep masseter and insertion of the temporalis on the medial face of the coronoid.  Of course this looks bit like Thrinaxodon -- presumably an interesting coincidence.

Images: Upper Right: Crocidura leucodon volgensis Stroganov, 1960.  Holotype.  From the Soricidae Catalogue of the Siberian Zoological Museum (former site).  Lower Right: Cryptotis parva from Discover Life.  

Links: Soricidae after Reumer, 1992, Nowak, 1991 and McKenna & Bell, ... (Mikko's Phylogeny); Soricidae collection of SZMN, Novosibirsk, Russia; APUS.RU | Семейство ·Землеройковые - Soricidae; Mammalia- Insectivora, Soricidae - Spitzmäuse (German); Molecular Phylogeny of Short-Tailed Shrews, Blarina (Insectivora ... (more recent speciation); Phylogeography of the dusky shrew, Sorex monticolus (Insectivora ... (more recent speciation); Soricidae (Philippine shrews); SORICIDAE 땃쥐과 (Korean); The Shrew (ist's) Site (indispensable site!).  

References: Asher et al. (2002) [A+02]; MacPhee & Novacek (1993) [MN93]; Nowak (1999) [N99]; Querouil et al. (2001) [Q+01]; Vaughan et al. (2000) [V+00].  ATW030816.

Crocidurinae: Crocidura, Myosorex, Suncus   

Range: Europe, Russia, North Africa, Arabia, Japan, South & Southeast Asia, North China, probably Siberia & Central Asia.  Mostly Africa [Q+01].  From the Miocene [Q+01].  

Phylogeny: Soricidae: Soricinae + *.

Characters: non-articulating strip between dentary condyles narrow [MN93]; teeth unpigmented; lower metabolic rate than soricines; highly social; more tropical distribution

Note: current belief is that crocidurines represent a Late Miocene African radiation of shrews that later spread to parts of Asia. [Q+01].   

Links: Soricidae- Crocidurinae (Mikko's Phylogeny); Eurasian Insectivores and Tree Shrews - Status Survey and ... (distribution); RESEARCH (interesting projects); Shrew ecology (notes on ecology, diversity & metabolism); Spitzmäuse (basic); Ecologie et Structuration des Peuplements de Micro- -mammifères ... (French: detailed study of factors affecting species abundance in Central Africa); Phylogeny and Evolution of African Shrews (Mammalia- Soricidae) ... (molecular phylogeny and zoogeography of African populations); Mammalia- Insectivora, Soricidae - Spitzmäuse.  

References: MacPhee & Novacek (1993) [MN93]; Querouil et al. (2001) [Q+01].  ATW030710.

Soricinae: Blarina, Chimarrogale, Sorex, Soriculus

Range: mostly Northern hemisphere [Q+01].  From the Miocene?

Phylogeny: Soricidae: Crocidurinae + *.

Characters: infraorbital canal long [A+02$]; transversely expanded, flat ectopterygoid plate on either side of choana [A+02$]; non- articulating strip between dentary condyles wide [MN93]; teeth pigmented (red) with iron in enamel layer [V+00]; I1 elongate, hooked with a notch [V+00]; remaining non-molar teeth are small, unicuspid and relatively uniform [V+00]; P4 large, with trenchant ridge [V+00]; upper molars with W-shaped ectoloph [V+00]; trigonids & talonids well-developed [V+00]; extremely high basal metabolic rate, requiring essentially continuous feeding; generally northerly distribution.

Links: Eurasian Insectivores and Tree Shrews - Status Survey and ... (diversity & natural history); SpringerLink - Content (article looking at physiology of high metabolic rate); Spitzmäuse (German: mostly diversity); Phylogeny and Evolution of African Shrews (Mammalia- Soricidae) ... (full text of important article); Shrew ecology; Insect Eaters(Insectivores) - Order Insectivora (some useful links); Cryptotis parva (Say); Least Shrew; Untitled; JVP 22(3) September 2002-ABSTRACTS 31A (why are the teeth pigmented).

References: Asher et al. (2002) [A+02]; MacPhee & Novacek (1993) [MN93]; Querouil et al. (2001) [Q+01]; Vaughan et al. (2000) [V+00].  ATW030714. 

checked ATW040725