Large-toothed shrew

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Large-toothed shrew
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Eulipotyphla
Family: Soricidae
Genus: Sorex
Species:
S. macrodon
Binomial name
Sorex macrodon
Merriam, 1895
Large-toothed Shrew area.png
Large-toothed shrew range

The large-toothed shrew or Mexican large-toothed shrew (Sorex macrodon) is one of 77 species within the genus Sorex . Registered on the IUCN Red List as vulnerable with a decreasing population, the Mexican large-toothed shrew has been recorded only 14 times in seven locations. The shrew is a member of the red-toothed shrew subfamily Soricinae, and the more taxonomically defined tribe Soricini. [2] Members of the latter category exhibit long tails relative to body size.

Contents

Habitat, distribution, and survival

With an estimated range around 6,400 to 12,000 km², S. macrodon is endemic to Mexico and occupies mossy banks, moist cloud forest, and dense oak forests, where it may live under rocks or logs, beside streams, and in weedy vegetation. [1] Mexican large-toothed shrews inhabit pine-oak, coniferous, and tropical forest growing inside the Trans-Mexican Volcanic Belt (TVB) within the southernmost Sierra Nevada. [3] This natural landmark is found inside the Gulf of Mexico, and is a recognized hotspot for diversity, endemicity, and geographic transition of living biology - it boasts more than 75% of the sporadic distribution of S. macrodon. [4] This particular species is entirely terrestrial; coincident species include: Megadontomis cryophilus, Peromyscus aztecus, and Peromyscus furvus. [5] S. macrodon shares extensive trails with Lepus callotis, and Microtus oaxacensis, as well as mountainous territory – at altitudes of 4200 meters - along with fellow shrews S. veraepacis, S. saussurei, and S. trowbridgii. [6] Species are micro endemic to the neotropics of Veracruz, Oaxaca, and Puebla in southern Mexico. [7] Uninhibited destruction of local forests continues to shrink its narrow habitat. In 2005, civilian development had rendered 84% of the shrew’s original range unsuitable. “Biological Conservation” records that only 15.95% of S. macrodon habitat remained ecologically intact after deforestation; less than 25% of their potential distributions endured. In farmland, shrews are likely to be affected by pesticides either through secondary contamination by the food chain or by direct exposure. Destruction of habitat boundaries, including markers such as forest limits and grass lines, diminish S. macrodon survival rates within small and sparse distribution. As a result, even small natural disasters or human interferences – such as mining operations, livestock ranching, wood-harvesting, or forest fires – could exterminate the entire population. [8] Unfortunately, the Mexican large-toothed shrew is very poorly known, even in its native country. In summary, agriculture and urbanization pose major extinction threats to Sorex macrodon. [9]

Diet

It is mainly insectivorous, and feeds on small arthropods, arachnids, and some plant material. [10]

Morphology

The Mexican large-toothed shrew is rather large with a total length of 11.8 cm or more and a hind foot of 1.5 cm. Its pelage is a comparatively light (to other shrews in the family) mixed russet and black, with chamois colored ventral parts. The skull of S. macrodon is large and heavy with bulky teeth and reinforced margins of the anterior nostrils. [11]

Phylogeny

S. macrodon is part of the Beringean clade, one of two major clades in North America, and shows an early divergence from other North American species. S. macrodon has a cytochrome b gene sequence of 1081 base pairs, about the median range of its relatives. The Mexican large-toothed shrew is inferred to have diverged from others in its clade during the late Miocene. [12]

Related Research Articles

<span class="mw-page-title-main">Shrew</span> Family of mammals

Shrews 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 different families or orders.

<span class="mw-page-title-main">Red-toothed shrew</span> Subfamily of mammals

The red-toothed shrews of the subfamily Soricinae are one of three living subfamilies of shrews, along with Crocidurinae and Myosoricinae. In addition, the family contains the extinct subfamilies Limnoecinae, Crocidosoricinae, Allosoricinae and Heterosoricinae. These species are typically found in North America, northern South America, Europe and northern Asia. The enamel of the tips of their teeth is reddish due to iron pigment. The iron deposits serve to harden the enamel and are concentrated in those parts of the teeth most subject to wear.

<span class="mw-page-title-main">American pygmy shrew</span> Species of mammal

The American pygmy shrew is a small shrew found in Northern Alaska, Canada, and the northern United States, south through the Appalachian Mountains. It was first discovered in 1831 by naturalist William Cane in Georgian Bay, Parry Sound.

<i>Sorex</i> Genus of mammals

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 subfamily Soricinae. They have 32 teeth.

The blackish deer mouse is a species of rodent in the family Cricetidae found only in Mexico, and is relatively poorly studied.

The Espíritu Santo antelope squirrel is a species of antelope squirrel in the family Sciuridae. It is endemic to Mexico, where it is known only from the island of Espíritu Santo in the Gulf of California. The species was originally described by Edward William Nelson and Edward Alphonso Goldman in 1909 as a subspecies of the white-tailed antelope squirrel, a wide-ranging species in the southwestern U.S. and Mexico. In 1938, Arthur H. Howell elevated the subspecies to full species status, on the basis of slightly larger skull proportions and the absence or reduction of the third upper premolar. Studies of DNA and chromosomes have variously suggested close relationships with Harris's antelope squirrels or other subspecies of white-tailed antelope squirrel. A 2007 comparison of DNA and morphological traits suggested the differences between Espíritu Santo squirrels and those on the Baja California peninsula and other islands were not enough to warrant distinct species but rather a subspecies of white-tailed antelope squirrels. Since 2008 the IUCN has similarly recognized the Espíritu Santo antelope squirrel as a subspecies of white-tailed antelope squirrel.

<span class="mw-page-title-main">Alpine shrew</span> Species of mammal

The alpine shrew is a species of mammal in the family Soricidae. It is found in the alpine meadows and coniferous forests of central and southern European mountain ranges.

<span class="mw-page-title-main">Arizona shrew</span> Species of mammal

The Arizona shrew is a species of shrew native to North America.

<span class="mw-page-title-main">Paramushir shrew</span> Species of mammal

The Paramushir shrew is a species of mammal in the family Soricidae. It is endemic to Russia. Its natural habitat is temperate forests. It is likely named for Paramushir Island, home to several other species of shrew in the genus Sorex.

<span class="mw-page-title-main">Dwarf shrew</span> Species of mammal

The dwarf shrew is a species of mammal in the family Soricidae endemic to Arizona, Colorado, Montana, Nebraska, New Mexico, South Dakota, Utah, and Wyoming in the United States. The type locality is Estes Park, Colorado, USA.

<span class="mw-page-title-main">Ornate shrew</span> Species of mammal

The ornate shrew is a species of mammal in the family Soricidae (shrews). It is endemic to western North America, ranging from Northern California in the United States to Baja California in Mexico. Eight subspecies are known, including the extinct tule shrew, known only from four specimens collected in 1905, and the Suisun ornate shrew, a species of conservation concern in California. Through skull morphology research and genetic testing on Ornate shrew populations, it has been shown that there are three main genetic subdivisions: The Southern, Central and Northern. These three genetic subdivisions of Ornate shrew arose from populations of Ornate shrews getting geographically isolated from other populations.

<span class="mw-page-title-main">Sclater's shrew</span> Species of mammal

Sclater's shrew is a species of mammal in the family Soricidae. It is endemic to Mexico.

<span class="mw-page-title-main">Fog shrew</span> Species of mammal

The fog shrew is a species of mammal in the family Soricidae. It is endemic to northern California and Oregon in the United States.

References

  1. 1 2 de Grammont, P.C.; Matson, J. (2018). "Sorex macrodon". IUCN Red List of Threatened Species . 2018: e.T20392A22314529. doi: 10.2305/IUCN.UK.2018-2.RLTS.T20392A22314529.en . Retrieved 11 November 2021.
  2. ↑ Myers, P; Espinosa, R.; Parr, C. S.; Jones, T.; Hammond, G. S; Dewey, T. A. (2017). "Sorex macrodon". The Animal Diversity Web.
  3. ↑ Amori, Giovanni; Chiozza, Federica; Rondinini, Carlo; Luiselli, Luca (2011). "Worldwide conservation hotspots for Soricomorpha focusing on endemic island taxa: an analysis at two taxonomic levels". Endangered Species Research. 15 (2): 143–149. doi: 10.3354/esr00377 .
  4. ↑ Gámez, Niza; Escalante, Tania; Rodrígues, Gerardo; Linaje, Miguel; Morrone, Juán J. (2007). Revista Mexicana de Biodiversidad. 83: 258–272.{{cite journal}}: Missing or empty |title= (help)
  5. ↑ Rogers, Duke; Skoy, James (2010). "Peromyscus furvus (Rodentia: Cricetidae)". Mammalian Species. 43 (888): 209–215. doi: 10.1644/888.1 .
  6. ↑ Escalante, Tania; Rodríguez, Gerardo; Morrone, Juán J. (2004). "The diversification of Nearctic mammals in the Mexican transition zone". 83: 327–339.{{cite journal}}: Cite journal requires |journal= (help)
  7. ↑ Escalante, Tania; Rodríguez, Gerardo; Gámez, Niza; León-Paniagua, Livia; Barrera, Omar; Sánchez-Cordero, Victor (2007). "Biogeografía y conservación de los mamíferos": 485–502.{{cite journal}}: Cite journal requires |journal= (help)
  8. ↑ Mares, Michael A. (1991). Latin American Mammalogy. Norman, Oklahoma: University of Oklahoma Press. p. 178.
  9. ↑ Sánchez-Cordero, Victor; Illoldi-Rangel, P.; Linaje, Miguel; Sarkar, Sahotra; Peterson, A. Townsend (2005). "Deforestation and extant distributions of Mexican endemic mammals". Biological Conservation. 126 (4): 465–473. doi:10.1016/j.biocon.2005.06.022.
  10. ↑ Cervantes, Fernando A.; Castro-Campillo, Alondra; Ramírez-Pulido, José (1994). "Mamíferos terrestres nativos de México". Anales Institucionales de Biología en la Universidad Nacional. 65 (1): 177–190.
  11. ↑ Merriam, C. Hart (1895). "Synopsis of the American shrews of the genus Sorex". North American Fauna. 10: 57–125. doi:10.3996/nafa.10.0003.
  12. ↑ Esteva, Martha; Cervantes, Fernando A.; brant, Sara V.; Cook, Joseph A. (2010). "Molecular phylogeny of long-tailed shrews (genus Sorex) from México and Guatemala". Zootaxa. 2615 (2615): 47–65. doi: 10.11646/zootaxa.2615.1.3 .
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