Tropical ground squirrel
| Tropical ground squirrel | ||||||||||||
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| Notocitellus adocetus | ||||||||||||
| ( Merriam , 1903) |
The tropical ground squirrel ( Notocitellus adocetus , syn .: Spermophilus adocetus ) is a species of squirrel from the genus Notocitellus . It occurs exclusively in the Sierra Nevada in west-central Mexico . The species is not considered endangered and can occur regionally as a pest in agricultural areas. It is possible that it has spread further through the increase in agricultural use in the peripheral area of its distribution area.
features
The tropical ground squirrel reaches a head-trunk length of about 16.8 to 19.4 centimeters and a tail length of 13 to 15 centimeters. The length of the tail corresponds to more than 75% and usually about 90% of the length of the head and torso and is therefore comparatively long for a ground squirrel. Both species of the genus have a black-gray speckled back, which results from the black-pale black banding of the back hair. The fur is rough compared to the rather soft fur of other species of ground squirrels. The body is long and slender, the tail is narrow and only slightly bushy and corresponds more to that of the tree squirrel than that of other ground squirrels.
The tropical ground squirrel differs from the very similar, but somewhat larger, ring- tailed ground squirrel ( Notocitellus annulatus ) primarily in its somewhat paler fur color, smaller ears and shorter and wider snout. He also has no tail rings. From other ground squirrels the region such as the Mexican ground squirrel ( ictidomys mexicanus ) and the rock squirrel ( otospermophilus variegatus ) it is distinguished mainly by the nine rows of bright spots on the back coat.
distribution
The tropical ground squirrel occurs only in west-central Mexico , where it is correspondingly endemic . The range is restricted to the Sierra Nevada , also known as the Transmexican Volcanic Belt, and includes parts of the Mexican states of Jalisco , Michoacán , Guerrero and México .
Way of life
The tropical ground squirrel lives mainly in the dry and stony habitats of the mountain regions of the Sierra Nevada, also on cliffs and in crevices. In addition, it is often found in agricultural areas, where it can cause significant damage to the crops. The natural vegetation of its habitat consists of prosopis bushes and cacti of the genus Cephalocereus .
The tropical ground squirrel lives on the ground and digs burrows that are up to 60 centimeters deep and branched out. It is diurnal, social, and active most of the year; However, in the summer with the highest temperatures there are occasional periods of rest. The animals are strictly granivorous if seeds are available, but otherwise omnivorous . Among other things, they eat the seeds and fruits of Acacia , Crescentia and Prunus species, and in agricultural areas they also feed on beans, maize and sorghum . The spread of agricultural areas in their range and in adjacent areas probably also resulted in an increase in the range of the animals. The animals communicate using high-pitched chirps when people or potential predators are nearby. So far only one louse has been described as an ectoparasite in this species, it is Neohaematopinus traubi .
Systematics
The tropical ground squirrel is classified as an independent species within the genus Notocitellus , which consists of two species and includes the ring- tailed ground squirrel ( Notocitellus annulatus ). The first scientific description comes from Clinton Hart Merriam from 1903, who described the species on the basis of individuals from La Salada about 40 kilometers south of Uruapan in the state of Michoacán. The two species have long been classified as part of the ground squirrel ( Spermophilus ), but after a comprehensive molecular biological investigation, Notocitellus is considered as an independent genus together with several other genera.
Within the species, together with the nominate form, three subspecies are distinguished:
- Notocitellus adocetus adocetus : nominate form; occurs in the state of Michoacán. The basic color is gray to sand-colored.
- Notocitellus adocetus arceliae : In Guerrero. There are drawings in V-shape on the tail and the incisor teeth are siena-colored .
- Notocitellus adocetus infernatus : In the southwestern part of the distribution area, also in Michoacán and the northern Guerrero. The subspecies is smaller and more conspicuously black on the snout than the nominate form.
According to Best 1995, Wilson & Reeder 2005 and Helgen et al. In 2009 only two subspecies of the species then listed as Spermophilus adocetus were distinguished, the nominate form Spermophilus adocetus adocetus and Spermophilus adocetus infernatus
Status, threat and protection
The tropical ground squirrel is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as "not endangered" (least concern). This is justified with the relatively large distribution area, the assumed large populations, the occurrence in several protected areas and the tolerance of the species to habitat changes. There are no known potential risks to the company's existence.
supporting documents
- ↑ a b c d e f g h Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 290-291. ISBN 978-1-4214-0469-1
- ↑ a b c d Kristofer M. Helgen, F. Russell Cole, Lauren E. Helgen, Don E. Wilson: Generic Revision in the holarctic ground squirrels genus Spermophilus. Journal of Mammalogy 90 (2), 2009; Pp. 270-305. doi : 10.1644 / 07-MAMM-A-309.1
- ↑ a b Spermophilus adocetus In: Don E. Wilson , DeeAnn M. Reeder (Ed.): Mammal Species of the World. A taxonomic and geographic Reference. 2 volumes. 3. Edition. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
- ↑ Matthew D. Herron, Todd A. Castoe, Christopher L. Parkinson: Sciurid phylogeny and the paraphyly of holarctic ground squirrels (Spermophilus). Molecular Phylogenetics and Evolution 31, 2004; Pp. 1015-1030. ( Full text , PMID 15120398 )
- ↑ Ticul Álvarez, José Ramírez-Pulidos: Descripción de una nueva subespecie de Spermophilus adocetus (Rodentia, Sciuridae) de Michoacán, México y estado Taxonómico de S. a. Arceliae (Villa R., 1942). Revista de la Sociedad Mexicana de Historia Natural 29, 1968; Pp. 181-189. ( Full text ).
- ^ Troy L. Best : Notocitellus adocetus. Mammalian Species 504, 1995.
- ↑ a b Notocitellus adocetus in the IUCN 2015-4 Red List of Threatened Species . Posted by: PC de Grammont, A. Cuarón, 2008. Retrieved January 10, 2016.
literature
- Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 290-291. ISBN 978-1-4214-0469-1
- Troy L. Best : Notocitellus adocetus. Mammalian Species 504, 1995.
Web links
- Notocitellus adocetus inthe IUCN 2015-4 Red List of Threatened Species . Posted by: PC de Grammont, A. Cuarón, 2008. Retrieved January 10, 2016.