Carruthers redshank squirrel
| Carruthers redshank squirrel | ||||||||||||
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| Scientific name | ||||||||||||
| Funisciurus carruthersi | ||||||||||||
| Thomas , 1906 |
The Carruthers redshank squirrel or mountain chipmunk ( Funisciurus carruthersi ) is a species of squirrel from the genus of the redshank squirrel ( Funisciurus ). It occurs in the mountainous regions of the Western Rift and the Ruwenzori Mountains in East Africa .
features
The Carruthers redshank squirrel reaches an average head-trunk length of 18.7 to 23.6 centimeters, the tail is 18.0 to 23.1 centimeters long. The weight is around 200 to 280 grams. The rear foot length is 46 to 50 millimeters, the ear length 17 to 20 millimeters. It is a medium-sized to large squirrel with a soft olive-green back fur that is interspersed with gray and black and is darker on the middle back than on the sides. The hair is long and soft, it is black or dark gray at the base, has a sand-colored-yellow or olive-green band and a black tip. Especially in the middle area along the spine there are long black feeler hairs. The sides of the body are lighter without black hair, the animals have no side stripes. The ventral side is gray or gray-white from the throat to the base of the tail, the hair is medium gray at the base and white to white-gray at the tip. The scrotum is olive green and corresponds in color to the sides of the body, the head and the cheeks. There is a noticeable creamy white eye ring around the eyes. The ears are small and dark in color and covered with scattered hair. The front edge of the ears is sharply angled and thus forms an intermediate shape between the more triangular ears of the redshank squirrel and the more rounded ears of the African bush squirrel. The front feet have four toes, the hind feet five, and all toes have well-developed claws. The color of the legs changes to a darker brown before the coat change. The tail is long and corresponds to the length of the head and trunk. It is colored ocher and black and indistinctly banded. The tail hair is long with an ocher base, a black center ring and an ocher tip. The females have three paired teats (1 + 2 = 6).
| 1 | · | 0 | · | 2 | · | 3 | = 22 |
| 1 | · | 0 | · | 1 | · | 3 |
The skull has a total length of 46.4 to 50.2 millimeters and a width of about 25.5 to 29.0 millimeters. Like all species of the genus has the type in the upper jaw half per one to a incisor tooth formed incisor (incisor) to which a tooth gap ( diastema follows). This is followed by two premolars and three molars . The teeth in the lower jaw correspond to those in the upper jaw, but only with a premolar. In total, the animals have a set of 22 teeth. The bony palate ends at the anterior margin of the last molars.
The Carruthers redshank squirrel is similar to various redshank squirrels, African bush squirrels, and sun squirrels . In terms of distribution, this mainly concerns the Ruwenzori sun squirrel ( Heliosciurus ruwenzorii ) and the red-footed sun squirrel ( Heliosciurus rufobrachium ), with which it sometimes occurs sympatric . Both are roughly the same size. The Ruwenzori sun squirrel has a gray back color, the belly color is white and the tail is gray with white banding. The red-footed sun squirrel has striking red or red-brown legs and feet, the tail is banded in black and white.
distribution
The Carruthers redshank squirrel occurs in the mountainous regions of the Western Rift and in the Ruwenzori Mountains in East Africa from southwest Uganda and the eastern area of the Democratic Republic of the Congo via Rwanda to northern Burundi .
Way of life
The Carruthers redshank squirrel lives mainly in mountain forests and occurs particularly in populations of Prunus africana and in northern areas in forests of the koso tree ( Hagenia abyssinica ). The animals prefer dense forest stands with an open canopy and a rich epiphyte growth and dense undergrowth. In the Democratic Republic of the Congo, they mainly occur near rivers. They can hardly survive in agricultural areas.
They are diurnal and, unlike other squirrels, are also active in the evening after dusk. They live as good climbers in the branches of the trees and look for their food primarily in the trees and bushes at all altitudes, very rarely also on the ground. Like other species of the genus, the animals feed primarily on herbivores , with a large part of the diet being various fruits such as those of Bridelia and Alchornea species, Carapa grandifolia and Strombosia scheffleri . Insects have so far only been found in small amounts as stomach contents. The animals are often found alone or in pairs. Communication takes place via various croaking or rattling sounds, although the meaning of the calls has not yet been investigated. Compared to the sun squirrels that occur in the same habitats, the animals are less conspicuous and well camouflaged by their coloration, and this is hardly visible even when they wag their tails. For this reason, it is assumed that these are not optical signals, but that the wagging of the tail primarily serves to distribute fragrances.
Very little information is available about the reproduction of the animals. So far, only one lactating female has been caught in southwest Uganda, and there is no documentation of nests and litters. Also on predators and parasites there is no information of this kind, as potential predators are Bonelli's Eagle ( Hieraaetus ) and other birds of prey as well as predators such as civets and the African golden cat ( Caracal aurata accepted).
Systematics
The Carruthers redshank squirrel is classified as an independent species within the genus of the redshank squirrel ( Funisciurus ), which consists of ten species. The first scientific description comes from the British zoologist Oldfield Thomas from 1906, who described the animals using two individuals, a male and a female, from the eastern Ruwenzori Mountains in Uganda. He received the animals together with other small mammals from the participants of the British Ruwenzori expedition 1905/1906 and named this species after Douglas Mitchell Carruthers , who took part as a naturalist and collected the specimens. The taxonomic assignment is unclear, as it shows characteristics of both the redshank squirrel and the African bush squirrel ( Paraxerus ); molecular biological studies are currently not available.
Within the species, three to four subspecies are distinguished together with the nominate form :
- Funisciurus carruthersi carruthersi : nominate form, occurs in the Ruwenzori Mountains in southwest Uganda and the eastern Democratic Republic of the Congo.
- Funisciurus carruthersi birungensis : The subspecies occurs in the mountainous regions of the Western Rift ( Albertgraben ) in the southeast of Uganda, in the east of the Democratic Republic of the Congo, in Rwanda and in the northwest of Burundi. The sides of the body are more yellowish green than the middle of the back. The tips of the ears have grayish-white hairs and the tail is colored white, black and ocher.
- Funisciurus carruthersi chrysippus : The subspecies lives in the northwest of Lake Tanganyika . The color of the abdomen of this form has yellow washings, the sides of the face and the ears are ocher colored. In Kingdon 2013 this subspecies is not listed.
- Funisciurus carruthersi tanganyikae : The subspecies lives in the mountains in the area of the northern Lake Tanganyika. The body color is darker than that of the nominate form and the legs are lighter colored ocher, with the feet being less light.
Status, threat and protection
The Carruthers redshank squirrel is listed as “least concern” by the International Union for Conservation of Nature and Natural Resources (IUCN). This is justified by the comparatively large distribution area and the assumed large populations of animals in their habitat with occurrence in several protected areas as well as their high adaptability to habitat changes. The main risks for the stocks are considered to be the extensive conversion of primary forests into agricultural areas as well as the regional deforestation of habitats for firewood and hunting for bushmeat . However, these threats are assessed as primarily local and not as threatening the existence of the species.
supporting documents
- ↑ a b c d e f g h i j k l m n o Jonathan Kingdon: Funisciurus carruthersi, Carruther's Rope Squirrel (Carruther's Mountain Squirrel). In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 49-50; ISBN 978-1-4081-2253-2 .
- ↑ a b c d Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 214-215. ISBN 978-1-4214-0469-1
- ↑ Peter Grubb: Genus Funisciurus, Rope Squirrels. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 46-48; ISBN 978-1-4081-2253-2 .
- ↑ a b c Funisciurus carruthersi in the IUCN 2016-2 Red List of Threatened Species . Posted by: J. Kerbis Peterhans, P. Grubb, 2008. Retrieved September 13, 2016.
- ↑ Funisciurus carruthersi . 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 .
- ↑ Oldfield Thomas : Description of new mammals from Mount Ruwenzori. Annals and Magazine of Natural History Series 7, Volume 8, 1906; P. 140. ( digitized version ).
literature
- Richard W. Thorington Jr. , John L. Koprowski, Michael A. Steele: Squirrels of the World. Johns Hopkins University Press, Baltimore MD 2012; Pp. 214-215. ISBN 978-1-4214-0469-1
- Jonathan Kingdon: Funisciurus carruthersi, Carruther's Rope Squirrel (Carruther's Mountain Squirrel). In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 49-50; ISBN 978-1-4081-2253-2 .
Web links
- Funisciurus carruthersi inthe IUCN 2016-2 Red List of Threatened Species . Posted by: J. Kerbis Peterhans, P. Grubb, 2008. Retrieved September 13, 2016.