The Iberian shrew or Lagranja shrew (''Sorex granarius'') is a species of mammal in the family Soricidae. It is found in

Portugal Portugal, officially the Portuguese Republic, In recognized minority languages of Portugal: :* mwl, República Pertuesa is a country located on the Iberian Peninsula, in Southwestern Europe, and whose territory also includes the Macaronesian ...

and

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = '' Plus ultra'' ( Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , ...

Description

Relative to other ''

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 ...

'' species, ''S. granarius'' is intermediate in size, with a total body length (including the tail) of approximately 103.6 mm and an average weight of 6.3 g. Adults are identified by their dark-colored back, which contrasts with their lighter tan sides and off-white belly. The fur of young shrews has only two discernible colors: the darker color on the back and the lighter color on the belly. In both adults and juveniles, the fur is also adapted for cold, damp habitats: each guard hair possesses an indentation along its length that helps to prevent water from reaching the body. The skull of ''S. granarius'' can be used to distinguish it from other species belonging to the European ''Sorex araneus'' group of shrews. Comparatively, the snout of ''S. granarius'' is small and flat, the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

possesses a diminished coronoid process and a narrow angular process, and the

temporal fossa The temporal fossa is a fossa (shallow depression) on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. Boundaries * Medial: frontal bone, parietal bone, temporal bone, and sphenoid bon ...

of the skull resembles a triangle.

Phylogeny

The ''Sorex araneus'' group of European shrews consists of ''S. araneus'', ''S. coronatus'', and ''S. granarius'', with all members belonging to the order

Soricomorpha Soricomorpha (from Greek "shrew-form") is a formerly used taxon within the class of mammals. In the past it formed a significant group within the former order Insectivora. However, Insectivora was shown to be polyphyletic and various new orders ...

and the family Soricidae. Because their morphology is virtually identical, species definitions rely primarily on genetic differences. The phylogenetic positioning of ''S. granarius'' has been historically difficult even with the use of genetic analyses, with mitochondrial DNA suggesting that it is more closely related to ''S. araneus'' and Y sex chromosomal markers implying a stronger relationship with ''S. coronatus''. Recent studies of X sex chromosomal markers and autosomal chromosome DNA have been found to offer greater support for the phylogenetic grouping of ''S. granarius'' with ''S. coronatus'', as opposed to the traditional grouping of ''S. granarius'' and ''S. araneus''.

Ecology

Distribution and Habitat

The distribution of ''S. granarius'' is lateral through the

Central System The Central System, Spanish and pt, Sistema Central, is one of the main systems of mountain ranges in the Iberian Peninsula. The 2,592 m high Pico Almanzor is its highest summit. The Central System is located just north of the 40th parallel ...

mountain range of the Iberian Peninsula and reaches Galicia, Spain in the north and the Tagus (Tejo) River in the south. There is also speculation of ''S. granarius'' cohabitation with ''S. coronatus'' in the

Iberian System Iberian refers to Iberia. Most commonly Iberian refers to: *Someone or something originating in the Iberian Peninsula, namely from Spain, Portugal, Gibraltar and Andorra. The term ''Iberian'' is also used to refer to anything pertaining to t ...

. In the wild, ''S. granarius'' is known to live in woody areas consisting of juniper (''Juniperus nana''), beech (''Fagus sylvatica''), Pyrenean oak (''Quercus pyrenaica''), Scots pine (''Pinus sylvestris''), evergreen oak (''Quercus rotundifolia''), ash (''Fraxinus''), or birch (''Betula'') at 500 to 2000 meter elevations.

Predators

Domestic cats (''Felis catus''), European wild cats (''Felis silvestris''), and barn owls (''Tyto alba'') have been noted to prey upon ''S. granarius''''.''

Genetics

Chromosomes

In the group of ''Sorex araneus'' shrews, males possess distinctive XY₁Y₂ sex chromosomes. The Y chromosome comprises two portions: the original Y sex chromosome (Y₁) and a portion that forms an arm of one of the autosomal chromosomes (Y₂). ''S. granarius'' is unique among this group because it possesses primarily

acrocentric The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers ...

chromosomes with only two pairs of

metacentric Metacentric may refer to: * Metacentric height The metacentric height (GM) is a measurement of the initial static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre. A large ...

chromosomes, whereas ''S. araneus'' has a complete set of metacentric chromosomes.

Telomeres

The telomere length and location of ''S. granarius'' further distinguish the organism from ''S. araneus'': ''S. araneus'' possesses small telomeres on each chromosome that range in size from 6.8 to 15.2 kb. The telomeres of ''S. granarius'' are located only on the short arms of the acrocentric chromosomes, and can reach lengths of approximately 300 kb, making them the largest mammalian telomeres described to date. These

mega-telomere A mega-telomere (also known as an ultra-long telomere or a class III telomere), is an extremely long telomere sequence that sits on the end of chromosomes and prevents the loss of genetic information during cell replication. Like regular telomer ...

s appear to preserve their impressive length through both the enzyme telomerase and active homologous recombination. Additionally, the intermittent repetitive sequences of ''S. granarius'' telomeres are infused with ribosomal DNA, and it is the only known

Eutheria Eutheria (; from Greek , 'good, right' and , 'beast'; ) is the clade consisting of all therian mammals that are more closely related to placentals than to marsupials. Eutherians are distinguished from noneutherians by various phenotypic t ...

n mammal with this feature.