Damara-Graumull

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Damara-Graumull
Damaraland mole-rat.jpg

Damara gray mullet ( Fukomys damarensis )

Systematics
Order : Rodents (Rodentia)
Subordination : Porcupine relatives (Hystricomorpha)
Partial order : Hystricognathi
Family : Sand graves (Bathyergidae)
Genre : Gray Owl ( Fukomys )
Type : Damara-Graumull
Scientific name
Fukomys damarensis
( Ogilby , 1838)

The Damara or Damaraland gray mull ( Fukomys damarensis , syn .: Cryptomys damarensis ) is a medium-sized species of the gray mull ( Fukomys ) within the sand graves (Bathyergidae). Like other gray moulins, it is adapted to an underground and burrowing way of life. The species is distributed in southern Africa from Namibia and Angola to the northwest of South Africa.

features

general characteristics

The Damara gray mull reaches a head-trunk length of 15.5 to 17.8 centimeters with a weight of 115 to 210 grams, the tail is very short with 2.1 to 2.4 centimeters in length. The males are on average slightly larger and heavier than the females. Using growth models, it could be demonstrated that the size difference results from an increased growth rate of the males over the entire development period and not from a different growth duration or period of growth.

The medium-sized species has a cylindrical body with a blunted snout, short legs and a short tail. The fur is short and thick, individual feeler hairs protrude from this, especially in the head area. The animals have a glossy beige or dark brown to brown-black color with a conspicuous white markings on the top of the head, which can contain individual speckles in the color of the coat. A light belly stripe may be present. Only one or both color morphs can occur within a colony. The animals in the southern areas are rather dark to black, those in Namibia rather beige. The head is blunt, the front incisor teeth are not furrowed and protrude beyond the lips, so they are visible from the outside even when the mouth is closed. The eyes are very small, external ears are missing. The fore and hind feet are hairless and pink in color. The tail is very short and reaches a maximum of 18% of the head-trunk length, it is naked and covered with individual hard feeler bristles. The females have two pairs of teats in the breast and one in the lumbar region, for a total of six teats.

The chromosome set consists of 2n = 74 or 78 (FN = 92) chromosomes.

Features of the skull

The skull is broad and flattened dorso-ventrally. It has a distinct crest and the zygomatic arches are curved far outwards. The infraorbital windows are comparatively small and tear-shaped.

Differences from related species

From the closely related Mashona gray mullet ( Fukomys darlingii ) in Zimbabwe and Mozambique , the Damara gray mullet differs in its slightly darker color and larger average size, as well as genetic characteristics such as the higher number of chromosomes. The African gray bull ( Cryptomys hottentotus ), which occurs in South Africa sympatric with the Damara gray bull, is on average somewhat smaller. It is gray in color and also has fewer chromosomes.

distribution

The Damara gray mull is distributed in southern Africa from the south of Namibia , Zambia and Angola over most of Botswana and the west of Zimbabwe to the north-west of South Africa. The habitats include the arid regions around Dordabis and Rheoboth in Namibia, the Kalahari regions in South Africa and also the marshland on the Okavango in Botswana.

Way of life

The habitats are typically found in open and sandy semi-desert areas and in the arenosols of the Kalahari with thorn bushes, savannah and grass vegetation. These areas are usually very dry with annual rainfall of 200 to 400 millimeters, the soil and construction temperatures range from 30 ° C in summer to 19 ° C in winter. Like other gray mulls, this species also lives largely underground in colonies with two to 14 animals. They dig burrows in the area of ​​vegetation and feed herbivore on thickened roots, tubers and other parts of plants. The animals have a regular circadian rhythm and dig mainly after rainfall. Within the colony only one pair of one, sometimes two, males and one female is capable of mating and is sexually active, the remaining individuals come from several generations and are not capable of reproduction. They take on the construction of the passages, the foraging for food and the defense of the colony. The animals are considered eusocial . As with the naked mole rat , the reproductive ability of the female is actively suppressed by the sexually active female. Individual animals and non-reproductive colony members spread out and create new burrows. The activity radius of the animals is one to three hectares.

There is no fixed mating and breeding season, young animals can be born throughout the year. The dominant female has offspring up to three times a year. The gestation period is about 78 to 92 days and the typical litter size consists of one to three young animals. The sex ratio of the young is balanced or slightly shifted in favor of the males. The young are naked at birth.

Systematics

The Damara gray mull is classified as an independent species within the genus of the gray mull ( Fukomys ), which consists of ten to fourteen species. The first scientific description comes from William Ogilby from 1838 as Bathyergus damarensis and was based on individuals from the region of what was then Damaraland in Namibia. Taxonomic synonyms of the species are Georychus lugadi de Winton 1998, Georychus micklemi Chubb 1909 and Cryptomuys ovamboensis Roberts 1946. The Damara gray mull was added to the African gray mull ( Cryptomys hottentotus ) as a subspecies by John Ellerman in 1953 , since the 1990s and at least since the mid-2000s Years, however, due to genetic and morphological characteristics, considered again as a separate species. In 2006 the genus Cryptomys was separated into two genus based on molecular biological characteristics, the Mashona-Graumul was assigned to the new genus Fukomys with most of the other species , but the split is not generally accepted.

Apart from the nominate form, no subspecies are distinguished within the species .

Status, threat and protection

The Damara-Graumull is classified by the International Union for Conservation of Nature and Natural Resources (IUCN) as Least Concern. This is justified with the frequent occurrence and the comparatively large distribution area. The species is also found in some protected areas and there are no risks to the population. The species can be found very frequently in suitable habitats and can sometimes reach up to 380 animals per square kilometer.

supporting documents

  1. ↑ a b c d e f g h i j k R. L. Honeycutt: Damara Mole-rat - Fukomys damarensis. 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; P. 370. ISBN 978-84-941892-3-4 .
  2. ↑ Jack Thorley, Tim H. Clutton-Brock: A unified-models analysis of the development of sexual size dimorphism in Damaraland mole-rats, Fukomys damarensis. Journal of Mammalogy 100 (4), July 27, 2019; Pp. 1374-1386. doi : 10.1093 / jmammal / gyz082
  3. ↑ a b c d e f g h i j k l m Nigel C. Bennett: Cryptomys damarensis - Damaraland Mole-Rat (Mashona Mole-Rat) In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (Ed.): Mammals of Africa Volume III. Rodents, Hares and Rabbits. Bloomsbury, London 2013, pp. 651-653; ISBN 978-1-4081-2253-2 .
  4. ↑ a b Fukomys damarensis in the IUCN Red List of Threatened Species 2016.2. Posted by: MF Child, S. Maree, 2008. Retrieved October 8, 2017.
  5. ^ William Ogilby : On a collection of Mammalia procured by Captain Alexander during his journey into the country of the Damaras. Proceedings of the Zoological Society of London, 1838; Pp. 5-6. ( Full text )
  6. ^ A b Colleen M. Ingram, Hynek Burda, Rodney L. Honeycutt: Molecular phylogenetics and taxonomy of the African mole-rats, genus Cryptomys and the new genus Coetomys Gray, 1864. Molecular Phylogenetics and Evolution 31 (3), 2004; Pp. 997-1014. doi : 10.1016 / j.ympev.2003.11.004
  7. ↑ Dieter Kock, Colleen M. Ingram, Lawrence J. Frabotta, Rodney L. Honeycutt, Hynek Burda: On the nomenclature of Bathyergidae and Fukomys n. Gen. (Mammalia: Rodentia). Zootaxa 1142, 2006; Pp. 51-55.
  8. ↑ Cryptomys damarensis . 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 .
  9. ↑ Nigel C. Bennett, Jennifer UM Jarvis: Cryptomys damarensis. Mammalian Species 756, December 12, 2004; Pp. 1-5. ( Full text ( memento of March 3, 2016 in the Internet Archive ))

literature

  • RL Honeycutt: Damara Mole-rat - Fukomys damarensis. 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; P. 370. ISBN 978-84-941892-3-4 .
  • Nigel C. Bennett: Cryptomys damarensis - Damaraland Mole-Rat (Mashona Mole-Rat) 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. 651-653; ISBN 978-1-4081-2253-2 .
  • Nigel C. Bennett, Jennifer UM Jarvis: Cryptomys damarensis. Mammalian Species 756, December 12, 2004; Pp. 1-5. ( Full text )

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