Allen chipmunk
| Allen chipmunk | ||||||||||||
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Allen Chipmunk at Lake Almanor, California |
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| Tamias senex | ||||||||||||
| JA Allen , 1890 |
The Allen chipmunk ( Tamias senex , Syn .: Neotamias senex ) is a type of squirrel from the genus of chipmunks ( Tamias ). It occurs in the American states of Oregon , California and Nevada . It is a medium-sized chipmunk that, like other chipmunks, lives primarily in trees and bushes, where it feeds mainly on various plant seeds and fruits. The species is assigned to a relationship complex around the Townsend chipmunk ( Tamias townsendii ) and is sometimes difficult to distinguish externally from other species in this complex. Important characteristics of the species are the gray washings in the fur on the back and other parts of the body, the clear light circles and stripes under the eyes and the stripes on the back that fade towards the back of the trunk.
The species is classified as “not endangered” by the International Union for Conservation of Nature and Natural Resources (IUCN) and the populations are considered stable.
features
The Allen chipmunk reaches an average head-trunk length of about 14.2 to 14.8 centimeters, the tail length is about 10.5 centimeters and the weight is about 80 to 95 grams. The species is comparatively large within the genus, but both body size and coat color vary widely within the range. The back color is red to cinnamon brown and, like other species of the genus, there are several dark back stripes on the back, which are separated by lighter stripes and delimited from the sides of the body. The head, the hips, the back area and parts of the tail are characterized by a gray wash. The middle back stripe is dark cinnamon brown to sepia-colored or black, on both sides there are more indistinct dark stripes, which are separated by white to gray-white stripes. All stripes fade out before they reach the hull. The thin tail is grayish with red-orange washings, it is often sand-colored, frosted.
The two white to sand-colored eye stripes are clearly formed and separated by an ocher-colored to orange-brown blindfold, the clearly formed eye ring is also sandy-brown to white. The light spots behind the ears (postauricular spots) are just as pronounced. The coastal population of the subspecies Tamias senex pacificus have a dark olive-brown basic color and a pink-gray belly. The domestic populations of the nominate form Tamias senex pacificus are lighter olive-gray with a light gray wash on the back, the belly is creamy white.
From Long Ear chipmunks ( Tamias quadrimaculatus ) of the Sierra Nevada , it is distinguished by the slightly grayer basic color and not so bright background eye spots. An important feature to distinguish it from other closely related chipmunks such as the yellow-cheeked chipmunk ( Tamias ochrogenys ) and the Siskiyou chipmunk ( Tamias siskiyou ) are the shape of the penis bone (baculum) and the clitoral bone (Baubellum) as well as genetic characteristics. In the case of the Siskiyou chipmunk, the inland forms are more similar in appearance to each other than the respective inland form and the coastal form.
Features of the skull
| 1 | · | 0 | · | 2 | · | 3 | = 22 |
| 1 | · | 0 | · | 1 | · | 3 |
The animals possess as all the subgenus Neotamias one to an associated species in the upper jaw and the lower jaw half per incisor tooth formed incisor (incisor) to which a tooth gap ( diastema follows). This is followed by two premolars in the upper jaw and one premolar and three molars in the lower jaw . In total, the animals have a set of 22 teeth.
Genetic traits
The genome of Sonoma strip croissant is like the other chipmunks from 38 chromosomes (2n = 38). These are five pairs of metacentric, six pairs of submetacentric and seven pairs of acrocentric autosomes . The X chromosome is submetacentric, the Y chromosome acrocentric. Within the genus, it is assigned to the type B karyotype.
distribution
The Allen chipmunk occurs from central Oregon south to California's Sierra Nevada and from the northwestern area of Nevada to Yosemite National Park in California.
Way of life
Allen chipmunks live mainly in undergrowth and bush-rich habitats in the primary forests at higher altitudes in the range, where they are sensitive to logging and other disturbances. This means that they are ecologically isolated from other species of chipmunk. In the coniferous forests and in the chaparral of the Sierra Nevada they often occur at altitudes of 1200 to 1800 meters
The species is diurnal and lives primarily on the ground or climbing in trees and bushes. The animals feed mainly on herbivores , with subterranean mushrooms making up a large part of the diet. In addition, there are seeds, fruits and other plant parts as well as insects as supplementary food. The hibernation takes place from November to March, the nests of the animals are mainly in trees. The territory of the animals covers an average of less than 3.5 ha , the size depends on the availability of food. Communication takes place via different "chip" sounds, the frequency of which is between those of other Tamias species such as the Siskiyou chipmunk ( Tamias siskiyou ) and the yellow-cheeked chipmunk ( Tamias ochrogenys ) and consists of three to five syllables per "chip" consist.
The mating season for this species is from March to April. The litter consists of three to five young animals on average. Weaning usually takes place at the end of June. In the greater part of the distribution area, the species comes sympatric with other chipmunks such as the mountain chipmunk ( Tamias alpinus ), the yellow spruce chipmunk ( Tamias amoenus ), rock chipmunk ( Tamias dorsalis ), the Merriam chipmunk ( Tamias merriami ), the long-eared chipmunk ( Tamias quadrimaculatus ), the Sonoma chipmunk ( Tamias sonomae ), the Lodgepole chipmunk ( Tamias speciosus ) and the Uinta chipmunk ( Tamias umbrinus ).
Predators are not documented; four types of fleas are known to be parasites , of which Monopsyllus ciliatus and Monopsyllus eumolpi are more common.
Systematics
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Possible relationship of the
Allan chipmunk
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The Allen chipmunk is classified as an independent species within the genus of chipmunks ( Tamias ), which consists of 25 species. The first scientific description comes from the American naturalist Joel Asaph Allen from 1890, who described it using individuals from the summit of Donner Pass in Placer County , California, and an individual from Oregon north of Fort Klamath . The type specimen came from the collection of Clinton Hart Merriam and was collected by CA Allen, to which the common name also refers. Daniel Giraud Elliot ordered the chipmunks 1901 with numerous other forms of the Townsend-chipmunks ( Tamias townsendii ) as a subspecies Tamias townsendiisenex to and it was classified according to the 1970s there until it by Dallas A. Sutton and F. Charles Nadler different result Features of cranial morphology and genital bones when Eutamias senex was restored to species rank.
Within the chipmunk group, the Allen chipmunk, along with most of the other species, is assigned to the subgenus Neotamias , which is also discussed as an independent genus. It is assigned to a group of species around the Townsend chipmunk called the townsendii group , along with some other species . Within this kinship group there are different kinship hypotheses. On the basis of molecular biological data, the Allen chipmunk is considered to be a sister species of the Sonoma chipmunk ( Tamias sonomae ) and both together are considered to be the sister group of the Townsend chipmunk. Alternatively, the Sonoma chipmunk is considered to be a sister species of a kindred of the Townsend chipmunk, Allen chipmunk, and Siskiyou chipmunk ( Tamias siskiyou ). In some cases, the Allan chipmunk was separated from the townsendii group together with the Siskiyou chipmunk and the yellow-cheeked chipmunk ( Tamias ochrogenys ) due to specific characteristics of the genital morphology , but this position is currently not recognized and the family relationship has been established on the basis of various other characteristics on the Townsend chipmunk again confirmed, including for example through the structure of the thighbone .
Within the species, together with the nominate form, two subspecies are distinguished:
- Tamias senex senex J.A. Allen, 1890 : nominate form; occurs in the entire inland region of the distribution area east of the coastal redwood forests in the Cascade Range , the Sierra Nevada and other mountain ranges. The subspecies is ocher with gray washings and it is slightly larger than the coastal form Tamias senex pacifica .
- Tamias senex pacificus Sutton & Patterson 2000 : lives in a narrow coastal strip of the distribution area in the area of the coastal redwood forests up to about 32 km inland. Its dark olive-brown color corresponds to that of the yellow-cheeked chipmunk ( Tamias ochrogenys ). The subspecies was described and established as a demarcation of the coastal form from the nominate form inland due to clear morphological differences. The original and common name form pacifica was changed to pacificus due to the grammatical gender .
Status, threat and protection
The Allen chipmunk is classified as Least Concern (LC) by the International Union for Conservation of Nature and Natural Resources (IUCN). This is justified by the relatively large distribution area and the regular occurrence; There are no known risks to the company's existence.
supporting documents
- ↑ a b c d e f g h i j k l Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 336-337 .
- ↑ a b c d e f J.L. Koprowski, EA Goldstein, KR Bennett, C. Pereira Mendes: Shadow Chipmunk. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, ISBN 978- 84-941892-3-4 , pp. 789-790.
- ↑ a b c d Dallas A. Sutton, Bruce D. Patterson: Geographic Variation of the Western Chipmunks Tamias Senex and T. Siskiyou, with Two New Subspecies from California. Journal of Mammalogy 81 (2), May 2000; Pp. 299-316. doi : 10.1644 / 1545-1542 (2000) 081 <0299: GVOTWC> 2.0.CO; 2
- ↑ a b Neotamias senex in the IUCN Red List of Threatened Species 2015.4. Submitted by: AV Linzey, NatureServe (G. Hammerson), 2008. Retrieved June 26, 2016.
- ^ A b Antoinette J. Piaggio, Greg S. Spicer: Molecular Phylogeny of the Chipmunk Genus Tamias Based on the Mitochondrial Cytochrome Oxidase Subunit II Gene. Journal of Mammalian Evolution 7 (3), September 2000, pp. 147-166, doi : 10.1023 / A: 1009484302799 . ( Full text )
- ^ A b Antoinette J. Piaggio, Greg S. Spicer: Molecular Phylogeny of the Chipmunks Inferred from Mitochondrial Cytochrome b and Cytochrome Oxidase II Gene Sequences. Molecular Phylogenetics and Evolution 20 (3), September 2001, pp. 335-350, doi : 10.1006 / mpev.2001.097 .
- ↑ a b Tamias (Neotamias) senex . In: Don E. Wilson , DeeAnn M. Reeder (Eds.): 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 .
- ^ A b Joel Asaph Allen : A review of some of the North American ground squirrels of the genus Tamias. Bulletin of the American Museum of Natural History 3, 1890; Pp. 45-116. ( Full text , description of the species on pp. 83–84)
- ^ William L. Gannon, Richard B. Forbes: Tamias senex. Mammalian Species 502, 1995; Pp. 1-6. doi : 10.2307 / 3504301
- ^ Daniel Giraud Elliot : A synopsis of the mammals of North America and the adjacent seas. Publication of the Field Columbian Museum, Zoological series v. 2, no. 1, 1901; P. 72. ( digitized version ).
- ^ Dallas A. Sutton, Charles F. Nadler: Systematic Revision of Three Townsend Chipmunks (Eutamias townsendii). The Southwestern Naturalist 19 (2) July 1974; Pp. 199-211. doi : 10.2307 / 3670280 .
- ↑ Bruce D. Patterson, Ryan W. Norris: Towards a uniform nomenclature for ground squirrels: the status of the Holarctic chipmunks. Mammalia 80 (3), May 2016; Pp. 241-251 doi : 10.1515 / mammalia-2015-0004
- ^ Noah Reid, John R. Demboski, Jack Sullivan: Phylogeny Estimation of the Radiation of Western North American Chipmunks (Tamias) in the Face of Introgression Using Reproductive Protein Genes. Systematic Biology 61 (1), 2012, pp. 44-62, doi : 10.1093 / sysbio / syr094 . PMC 3243737 (free full text)
- ^ Adrian Scheidt, Jan Wölfer, John A. Nyakatura: The evolution of femoral cross-sectional properties in sciuromorph rodents: Influence of body mass and locomotor ecology. Journal of Morphology, June 2019; Pp. 1-14. doi : 10.1002 / jmor.21007 .
literature
- JL Koprowski, EA Goldstein, KR Bennett, C. Pereira Mendes: Shadow Chipmunk. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (Eds.): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6) Lynx Edicions, Barcelona 2016, ISBN 978- 84-941892-3-4 , pp. 789-790.
- Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012, ISBN 978-1-4214-0469-1 , pp. 336-337 .
- William L. Gannon, Richard B. Forbes: Tamias senex. Mammalian Species 502, 1995; Pp. 1-6. doi : 10.2307 / 3504301
Web links
- Neotamias senex inthe IUCN Red List of Threatened Species 2015.4. Submitted by: AV Linzey, NatureServe (G. Hammerson), 2008. Retrieved June 26, 2016.