Cryptotis nelsoni 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Eulipotyphla Soricidae

Scientific Name: Cryptotis nelsoni
Species Authority: (Merriam, 1895)
Common Name(s):
English Nelson's Small Eared Shrew

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(i,ii,iii) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-14
Assessor(s): Woodman, N., Matson, J., Cuarón, A.D. & de Grammont, P.C.
Reviewer(s): Amori, G. & Chiozza, F.
Listed as Critically Endangered because its extent of occurrence is less than 100 km², it is known from only one location, and there is continuing decline in the extent and quality of its habitat.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Until recently, this species was known only from the type locality; which is on the western slope of the extinct Volcán San Martín Tuxtla in Veracruz, Mexico (Hutterer 2005). It has been recorded from 1,463 m up to the summit of the volcano at 1,650 m asl (Goldman 1951). Recently, it was found at three additional localities in the vicinity of the type locality (Cervantes and Guevara 2009). These localities lie on the south face of the volcano and just to the north west of the nearby Catemaco Lake (Cervantes and Guevara 2009). It has been hypothesized that this shrew probably occurs in suitable habitats throughout that Sierra (Choate1970). However, a recent study on the mammalian diversity of Sierra de Santa Martha, Veracruz did not record the presence of this species (Gonzalez Christen 2008).
Countries occurrence:
Mexico (Veracruz)
Additional data:
Lower elevation limit (metres):1460
Upper elevation limit (metres):1650
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It was considered common when collected by Goldman (1951). One adult male, one male juvenile, and one female adult have been recently found by Cervantes and colleagues (Cervantes and Guevara 2009).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:

The habitat reported by Merriam (1895) for the holotype and paratypes was evergreen tropical forest, represented by well-conserved vegetation that consisted of areas covered by layers of volcanic sand and ashes and trees of large size (Choate 1970, Goldman1951). The lower section of its range, from 1,460 to 1,525 m asl, is within dense primary forest; above this elevation it is montane grassland. The vegetation where the recently discovered specimens were obtained was cloud forest. In one of the three localities sampled, at 1,500m, the trees of the canopy were unusually low (Cervantes and Guevara 2009). It is an insectivorous species, feeding exclusively on insects.


Threats [top]

Major Threat(s): The habitat of C. nelsoni is gradually changing or disappearing due to the use of land within the Los Tuxtlas Biosphere Reserve. The activities within the reserve frequently involve logging, cattle grazing, induced fires, and crops (Cervantes and Guevara 2009) . In the area of the type locality, deforestation is as much as 90% and the annual deforestation rate is 6.2% (Dirzo and Garcia 1992).

Conservation Actions [top]

Conservation Actions: Part of the distribution is included in the Los Tuxtlas Biosphere Reserve and Los Tuxtlas Biological Station. According to Cervantes and Guevara (2009), a specific conservation action plan is needed in order to buffer and eventually halt alterations of the habitat and protect the integrity of the populations of this species.

Classifications [top]

1. Forest -> 1.9. Forest - Subtropical/Tropical Moist Montane
suitability:Suitable  major importance:Yes
4. Grassland -> 4.7. Grassland - Subtropical/Tropical High Altitude
suitability:Suitable  major importance:Yes
1. Land/water protection -> 1.2. Resource & habitat protection
2. Land/water management -> 2.1. Site/area management

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
  Occur in at least one PA:Yes
In-Place Species Management
In-Place Education
1. Residential & commercial development -> 1.1. Housing & urban areas
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion

2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.2. Small-holder farming
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.1. Ecosystem conversion

2. Agriculture & aquaculture -> 2.3. Livestock farming & ranching -> 2.3.2. Small-holder grazing, ranching or farming
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

5. Biological resource use -> 5.3. Logging & wood harvesting -> 5.3.5. Motivation Unknown/Unrecorded
♦ timing:Ongoing    
→ Stresses
  • 1. Ecosystem stresses -> 1.2. Ecosystem degradation

1. Research -> 1.2. Population size, distribution & trends
1. Research -> 1.3. Life history & ecology
1. Research -> 1.5. Threats
1. Research -> 1.6. Actions
2. Conservation Planning -> 2.2. Area-based Management Plan
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Carraway, L.N. 2007. Shrews (Eulypotyphla: Soricidae) of Mexico. Western North American Naturalist 3.

Cervantes, F. A., and Guevara, L. 2009. Rediscovery of the critically endangered Nelson’s small-eared shrew (Cryptotis nelsoni), endemic to Volcán San Martín, Eastern México. Mammalian Biology.

Choate, J.R. 1970. Systematics and zoogeography of the Middle American shrews of the genus Cryptotis. University of Kansas Publications, Museum of Natural History 19: 195-317.

Dirzo, R. and Garcia, M. C. 1992. Rates of deforestation in Los Tuxtlas, a neotropical area in Veracruz, Mexico. Conservation Biology 6(1): 84-90.

Goldman, E.A. 1951. Biological investigations in Mexico. Smithsonian Miscellaneous Collections 115: 1-476.

Gonzalez Christen, A. 2008. La diversidad alfa, beta y gamma de la mastofauna en la Sierra de Santa Marta, Veracruz, Mexico. In: Lorenzo, C., Espinoza, E., and Ortega, J. (eds), Avances en el Estudio de los Mamiferos de Mexico, Asociacion Mexicana de Mastozoologia, San Cristobal de las Casas, Chiapas, Mexico.

Hutterer, R. 2005. Order Soricomorpha. In: D.E. Wilson and D.M. Reeder (eds), Mammal Species of the World, pp. 220-311. Johns Hopkins University Press, Baltimore, Maryland, USA.

IUCN. 2010. IUCN Red List of Threatened Species (ver. 2010.4). Available at: (Accessed: 27 October 2010).

Merriam , C.H. 1895. Revision of the shrews of the American genera Blarina and Notiosorex. NorthAm. Fauna 10: 1-34.

Nowak, R.M. 1999. Walker's Mammals of the World. The Johns Hopkins University Press, Baltimore, USA and London, UK.

Citation: Woodman, N., Matson, J., Cuarón, A.D. & de Grammont, P.C. 2010. Cryptotis nelsoni. In: The IUCN Red List of Threatened Species 2010: e.T136389A4284838. . Downloaded on 22 January 2017.
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