Palmer chipmunk

from Wikipedia, the free encyclopedia
Palmer chipmunk
Palmer chipmunk

Palmer chipmunk

Systematics
Subordination : Squirrel relatives (Sciuromorpha)
Family : Squirrel (Sciuridae)
Subfamily : Ground Squirrel (Xerinae)
Tribe : Real ground squirrels (Marmotini)
Genre : Chipmunk ( Tamias )
Type : Palmer chipmunk
Scientific name
Tamias palmeri
( Merriam , 1897)

The Palmer chipmunk ( Tamias palmeri , Syn .: Neotamias palmeri ) is a type of squirrel from the genus of the chipmunk ( Tamias ). It occurs isolated in the high altitudes of the Spring Mountains in the south of the American state Nevada near the city of Las Vegas . In the lower mountain ranges the species competes for habitats, especially with the somewhat smaller Panamint chipmunk ( Tamias panamintinus ), which is more competitive especially in the drier areas; Due to global warming and the associated spread of drought-adapted vegetation into higher areas, the habitat of the Palmer chipmunk is further restricted. It is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as "Endangered" (EN) due to its limited range.

features

The Palmer chipmunk reaches an average head-torso length of about 12.5 centimeters, the tail length is about 8.0 to 10.0 centimeters and the weight is about 50 to 60 grams. There is no sexual dimorphism in terms of size and color, and accordingly there is no external difference between males and females. The back color is brown to dark brown with a yellowish-brown coloration, the shoulders gray and the belly is pale in color. As with other species of the genus, the fur is brown and on the back there are several dark red- to black-brown back stripes, which are separated by lighter stripes and delimited from the sides of the body. The genome consists of a diploid chromosome set of 2n = 38 chromosomes.

1 · 0 · 2 · 3  =  22
1 · 0 · 1 · 3
Tooth formula of the chipmunks of the subgenus Neotamias

The skull of the animals has a total length of 34.9 to 36.5, on average 35.9 millimeters, in the area of ​​the zygomatic arches the width is 19.1 to 19.9, on average 19.6 millimeters. The animals have like all chipmunks the subgenus Neotamias maxillary and mandibular per half an an incisor tooth trained incisors (incisive) 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 .

Compared to sympatric occurring Panamint chipmunks ( Tamias panamintinus ) it is slightly larger and differs from it by grayer shoulders, strong colored black and white stripes and a back more tan -gelbliche coloring and a paler underside of tail. The skull is also narrower and less flattened, the upper incisors and molars are larger, and the zygomatic arches are more parallel. Compared to the closely related Uinta chipmunk ( Tamias umbrinus ), with which the distribution area does not overlap due to the isolation, the Palmer chipmunk has more brownish or reddish brown stripes on the back, a stronger tan coloration of the underside of the tail as well as a shorter snout area and shorter incisors. Both have the same genome , with slight differences in the shape of the penis bone .

distribution

Distribution area of ​​the Palmer chipmunk

The Palmer chipmunk is isolated and endemic only to the Spring Mountains in Clark County in the Las Vegas area in the south of the American state of Nevada , which are surrounded by desert areas.

Way of life

Palmer chipmunks only live at altitudes of around 2100 meters to the tree line at an altitude of around 3600 meters, with the highest population densities occurring at 2400 to 2550 meters. The habitats are usually characterized by crevices, rocky and stony surfaces, caves and dead wood . The vegetation can be different and consists of mixed stands of the awn pine ( Pinus aristata ), the single-leaved pine ( Pinus monophylla ), the long-lived pine ( Pinus longaeva ) and the Utah juniper ( Juniperus osteosperma ), the Colorado fir ( Abies concolor ) and the yellow pine ( Pinus ponderosa ) as well as Cercocarpus ledifolius and Arctostaphylos pungens .

The species is diurnal and primarily ground-living, but can also climb trees and bushes. The animals feed mainly herbivorous of seeds and fruits, the main component of the diet are the seeds of the conifers are. In addition, lichens, fungi, insects and other parts of plants are used as supplementary food. Like other squirrels, they are important dispersal factors for the seeds of the tree species on which they feed. The males are more territorial and at times more aggressive towards other conspecifics than the females. The animals communicate via barking “chips” and “chucks” as well as howling noises. The most common “chips” emit 5 to 17 calls per 5 seconds, with the females reaching higher frequencies than the males.

Little data is available on reproduction. It is believed that the breeding season is from April to May and the young are born from late May to June, the gestation period is probably more than 33 days. The litters consist of an average of four young animals, but females with up to seven embryos were also caught.

Above 2500 meters, the Palmer chipmunk is the most common diurnal mammal. It lives sympatric with the Panamint chipmunks ( Tamias panamintinus ), which, however, occurs usually in lower altitudes below 2,500 meters. In areas where both species live, the more competitive Palmer chipmunk is displacing the Panamint chipmunk from mixed forest habitats that can be used for both species into rocky and drier peripheral areas that can only be used by this one. Other types of squirrel with which the distribution area of ​​the Palmer chipmunk overlaps are the gold- coated ground squirrel ( Callospermophilus lateralis ) in the lower elevations and the rock ground squirrel ( Otospermophilus variegatus ) in the rocky areas. Various predators and birds of prey can be used as predators , including the long-tailed weasel ( Mustela frenata ) and the red-tailed buzzard ( Buteo jamaicensis ). As parasites of are scratch worm moniliformis moniliformis that nematodes Heteroxynema cucullatum , Pterygodermatites coloradensis and Sypahcia eutamii and the flea Monopsyllus eumolpi documented.

Systematics

The Palmer chipmunk is classified as a separate species within the genus of chipmunks ( Tamias ), which consists of 25 species. The first scientific description comes from the American naturalist Clinton Hart Merriam from 1897, who described it as Eutamias palmeri using an individual from Mount Charleston in Clark County, Nevada, from an altitude of 2,450 meters. The species was named after Theodore Sherman Palmer , who collected the type on a joint expedition with Edward William Nelson on Mount Charleston and gave it to Merriam.

Within the chipmunk group, the Palmer chipmunk, along with most of the other species, is assigned to the subgenus Neotamias , which is also discussed as an independent genus. It is also assigned to the Tamias dorsalis group and is partially regarded as a subspecies of the Uinta chipmunk ( Tamias umbrinus ). This view is supported by both morphological and molecular biological investigations through the genetic proximity to the Uinta chipmunk and the lack or only slight expression of morphological differences when looking at the penis bones (baccullum) and the clitoris bones (baubellum) . Apart from the nominate form , no further subspecies are distinguished.

Status, threat and protection

The Palmer chipmunk is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as “Endangered” (EN). This is justified by the limited distribution area of ​​less than 5,000 km 2 , where the species is limited to a mountain range and above all a mountain and the necessary water resources. The species is part of the Clark County's Multi Species habitat Conservation Plan and the Nevada Natural Heritage Program due to its limited range , and is considered Threatened in the State of Nevada. Habitat changes due to increasing settlement around Las Vegas, logging and the increase in domestic cats and domestic dogs in the range of the species are regarded as endangering risks . Added to this is the increase in fires, which are mainly attributed to the increased use of leisure time in the region and the warming of the climate; For example, a 2013 fire destroyed 11,300 acres of forest in the Spring Mountains. As a result of global warming, the spread of heat-loving and more drought-resistant tree species in parts of the habitats that support the displacement of the Palmer chipmunk by the Panamint chipmunk, which is better adapted to these habitats, is increasing.

supporting documents

  1. ↑ a b c d e f g h i j k Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 330-331. ISBN 978-1-4214-0469-1 .
  2. ↑ a b J.L. Koprowski, EA Goldstein, KR Bennett, C. Pereira Mendes: Palmer's Chipmunk. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; Pp. 792-793. ISBN 978-84-941892-3-4
  3. ↑ a b c d Troy L. Best : Tamias palmeri. Mammalian Species 443, 1993.
  4. ↑ a b c d Neotamias palmeri in the IUCN Red List of Threatened Species 2015.4. Listed by: C. Lowrey, AV Linzey, NatureServe (G. Hammerson), 2008. Retrieved June 17, 2016.
  5. ↑ a b c d e f g Christopher Lowrey, Kathleen Longshore, Brett Riddle, Stacy Mantooth: Ecology, distribution, and predictive occurrence modeling of Palmer's chipmunk (Tamias palmeri): a high-elevation small mammal endemic to the Spring Mountains in southern Nevada , UNITED STATES. Journal of Mammalogy 97 (4), March 10, 2016; Pp. 1033-1043. doi : 10.1093 / jmammal / gyw026 .
  6. ↑ Christopher Lowrey, Kathleen Longshore: Habitat Interaction Between Two Species of Chipmunk in the Basin and Range Province of Nevada. Western North American Naturalist 73 (2), 2013; Pp. 129-136. doi : 10.3398 / 064.073.0202 .
  7. ↑ Christopher Lowrey, Kathleen Longshore: Palmer's Chipmunk (Tamias palmeri). Ecology and Monitoring Protocols in the Spring Mountains National Recreation Area, Nevada. Study for the Clark County Multiple Species Habitat Conservation Plan, United States Geological Survey 2005 (Draft); Pp. 4-5; Retrieved October 18, 2016.
  8. ↑ a b Tamias (Neotamias) palmeri 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 .
  9. ↑ a b Clinton Hart Merriam : Notes on the chipmunks of the genus Eutamias occurring west to the east base of the Cascade-Sierra system, with descriptions of new forms. Proceedings of the biological society of Washington 11, 1897; Pp. 189-212. (First description of Eutamias palmeri from pp. 208–210; digitized version )
  10. ↑ Bo Beolens, Michael Grayson, Michael Watkins: The Eponym Dictionary of Mammals. Johns Hopkins University Press, 2009; Pp. 305-306; ISBN 978-0-8018-9304-9 .
  11. ↑ 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
  12. ↑ Jenner L. Banbury, Greg S. Spicer: Molecular Systematics of Chipmunks (Neotamias) Inferred by Mitochondrial Control Region Sequences. Journal of Mammalian Evolution 14 (3), 2007; Pp. 149-162. doi : 10.1007 / s10914-006-9035-1 .
  13. ^ 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), 2000; Pp. 147-166. doi : 10.1023 / A: 1009484302799 .

literature

  • Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 330-331. ISBN 978-1-4214-0469-1
  • Troy L. Bestt : Tamias palmeri. Mammalian Species 443, 1993.
  • JL Koprowski, EA Goldstein, KR Bennett, C. Pereira Mendes: Palmer's Chipmunk. In: Don E. Wilson, TE Lacher, Jr., Russell A. Mittermeier (editors): Handbook of the Mammals of the World: Lagomorphs and Rodents 1. (HMW, Volume 6), Lynx Edicions, Barcelona 2016; Pp. 792-793. ISBN 978-84-941892-3-4
  • Christopher Lowrey, Kathleen Longshore, Brett Riddle, Stacy Mantooth: Ecology, distribution, and predictive occurrence modeling of Palmer's chipmunk (Tamias palmeri): a high-elevation small mammal endemic to the Spring Mountains in southern Nevada, USA. Journal of Mammalogy 97 (4), March 10, 2016; Pp. 1033-1043. doi : 10.3398 / 064.073.0202 .

Web links