Van Zyl's gold mole

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Van Zyl's gold mole
Systematics
Superordinate : Afrotheria
without rank: Afroinsectiphilia
Order : Tenrecus (Afrosoricida)
Family : Gold mole (Chrysochloridae)
Genre : Cryptochloris
Type : Van Zyl's gold mole
Scientific name
Cryptochloris zyli
Shortridge & Carter , 1938

Van Zyl Goldmull ( cryptochloris Zyli ) is a little-known mammalian species from the family of the golden moles (Chrysochloridae). It is only known about a few individuals from southwest Africa who belong to two spatially separated subpopulations , the species is therefore extremely rare. The animals inhabit sandy habitats and are adapted to an underground way of life with a diamond-shaped body without externally visible ears and tail, as well as with powerful grave claws. However, they also spend part of their activities on the earth's surface, but the way of life is considered to be practically unexplored. The stock is classified as endangered, which among other things results from the habitat that is heavily influenced by mining . The first description of Van Zyl Goldmull carried 1938th

features

Habitus

Van Zyls Goldmull is one of the smallest representatives of the goldmulle, but it is only known from a few specimens. The head-torso length of the holotype specimen is 8.2 cm, measurements of the body weight are not available, and no information can be given on a possible gender dimorphism . The physique corresponds roughly to that of the other gold mole, but it is significantly shorter and more diamond-shaped. The ears and tail are not externally visible. The fur looks dense and short, on the back it has a dark lead-gray color. Coarser guide hairs have a pale pink shimmering tone, which gives the animals a glittering appearance. The undercoat , on the other hand, appears smoky gray. The belly is colored similar to the back, but a bit lighter and more monotonous. Whitish patches of color appear on the face, mixed with darker hair and highlighting the area up to the fur-covered eyes. The limbs are powerfully built, the hands have four, the feet five rays. All fingers and toes have long but slender claws, the largest dimensions being 10 mm long and 4 mm basal width being those of the middle finger. The claws of the second and first fingers are 8 and 6.5 mm respectively, almost the same length and only slightly shorter than those on the middle finger. In contrast to other gold bulls, the fourth finger has a well-developed claw that becomes around 2 mm long. A noteworthy feature is a wide pad that appears at the edge of the first finger and noticeably broadens the forefoot, which also occurs in De Winton's gold mole ( Cryptochloris wintoni ), but not in the other gold mole. The rear foot reaches a length of 12 mm.

Skull and dentition features

The greatest length of the skull is between 21.7 and 22.2 mm, the greatest width between 15.0 and 15.2 mm. It is short and wide, but somewhat slimmer than the desert gold mole ( Eremitalpa granti ). The greatest width reaches 70 to 76% of the greatest length. The rostrum is also comparatively wide with a palate width of 8 mm, which corresponds to about 35 to 37% of the largest skull length. As a characteristic feature, the hammer in the middle ear has a club-like, elongated head, the dimensions of which, however, do not reach those of De Winton's gold mole or even the Cape gold mole ( Chrysochloris ). As a result, the bony bulge that is externally visible on the temporal fossa and that receives the head of the hammer is not quite as conspicuous. The dentition consists of 40 teeth, the dental formula is: . The rearmost molar is small in shape, but like the anterior molars has a tricuspid chewing surface pattern. There is no strong talonid on the lower molars. The length of the upper row of teeth from the canine to the last molar is about 8 mm, measured from the first incisor 10 mm.

distribution

Distribution area (red) of Van Zyl's gold mole

Van Zyl's gold mole is endemic to Africa . It occurs there in the south-western dry zone of the Karoo . Originally the species was only occupied by one locality near Lamberts Bay in the South African province of Western Cape , another individual was observed in 2003 around 150 km further north near the mouth of the Groenrivier in Namaqualand in the province of Northern Cape . The entire distribution area covers an area of ​​5000 km², the actual occurrence is limited to around 32 km². The animals prefer soft sandy soils of the coastal dune belt and adjacent sandy areas of the Succulent Karoo. They appear only very rarely, overall only a few individuals have been observed so far. The desert gold mole appears sympatric in the same area .

Way of life

Due to the rare occurrence of Van Zyl's gold mole, almost nothing is known about his way of life. It lives underground and digs tunnels close to the surface, which, however, like the desert gold mole, quickly collapse due to the loose sand material, leaving behind easily recognizable linear structures on the surface. The corridors only remain more stable for a short time when it rains. Lower living chambers are often protected in the roots of bushes. When touched, the animals make a high-pitched, squeaking sound. In the event of a threat, they also leave their traditional region and move a few hundred meters further at night. Based on surface tracks it is assumed that the species is more frequently active on the earth's surface.

Systematics

Van Zyl's gold mole is a species from the genus Cryptochloris , to which De Winton's gold mole ( Cryptochloris wintoni ) also belongs. Cryptochloris, on the other hand, belongs to the family of the gold mole (Chrysochloridae), small, soil-digging mammals from the parentage of the Afrotheria . The golden mole are endemic to Africa , the main area of ​​distribution is in the southern part of the continent, a few species also live in the eastern or central part. The animals inhabit dry to desert-like landscapes as well as open grass and savannah regions and forests. Their subterranean way of life means that they form habitat specialists with often very limited habitats. Based on the shape of the hammer in the middle ear - whether enlarged or not - two to three subfamilies are distinguished. Molecular genetic studies have not yet been able to understand this in every detail. With regard to Cryptochloris , however, both the skeletal anatomical and the genetic data showed a closer relationship with the Cape Goldmulls ( Chrysochloris ). The representatives of both genera have a club-like elongated head of the malleus, which in Cryptochloris is not quite as distinct and extremely elongated as in Chrysochloris . However, the former genus could also be a synonym for the latter, which was already adopted in the 1950s and 1960s. More recent analyzes from 2018 support this view.

The first scientific description of Van Zyl's Goldmull was carried out in 1938 by Guy Chester Shortridge and Donald Carter . At the same time they established the new genus Cryptochloris with the species and provided De Winton's gold mole ( Cryptochloris wintoni ) with it. Their description was based on a male individual from the Compagnies Drift about 16 km inland from Lamberts Bay in the South African province of Western Cape , which is considered a type locality. The animal was picked up on January 13, 1937 by the landowner Gideon van Zyl and is now in the Amathole Museum in King William's Town in the Eastern Cape Province . In honor of the finder, Shortridge and Carter gave the species name zyli . Evidently van Zyl had collected another individual the following year, which is kept in the Museum of Comparative Zoology at Harvard University and is identified as a paratype , but is not mentioned in the first description. In the 1950s and 1960s, Van Zyls Goldmull was viewed as a subspecies of De Winton's Goldmull, but it has been considered to be independent again since the early 1970s. In addition to the color of the fur, there are also differences between the two species in the design of the hammer in the middle ear, which in De Winton's Goldmull is rather bloated and less elongated than in Van Zyl's Goldmull.

Threat and protection

The coastal dune areas of south-western Africa are threatened by landscape destruction, which is largely caused by the extraction of diamonds and heavy metals . The mining area of ​​Hondeklipbaai is only 60 km south of the newly discovered subpopulation of Van Zyls Goldmull at the mouth of the Groenrivier and is constantly expanding. Further threats to the existence can be found in the construction of wind farms, for example at the type locality and in the development of the coastal region for tourism. The species is on the IUCN (as "critically endangered" endangered ) listed. The northern subpopulation on the Groenrivier lies within the Namaqua National Park . What is superficially necessary is an exact mapping of the exact distribution and research into the way of life of Van Zyl's gold mole.

literature

  • Gary N. Bronner: Cryptochloris zyli Van Zyl's Golden-mole. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 251-252
  • Gary N. Bronner and Nigel C. Bennett: Cryptochloris zyli Shortridge & Carter, 1938. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, p. 6
  • William A. Taylor, Samantha Mynhardt and Sarita Maree: Chrysochloridae (Golden moles). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 180–203 (p. 202) ISBN 978-84-16728-08-4

Individual evidence

  1. ↑ a b Guy Chester Shortridge: Field notes on the first and second expeditions of the Cape Museum 'Mammal survey of the Cape Province; and descriptions of some new subgenera and subspecies. Annals of the South African Museum 36, 1942, pp. 27-100 ( [1] )
  2. ^ Robert Broom: Some new and some rare Golden moles. Annals of the Transvaal Museum 20, 1946, pp. 329-335
  3. ↑ a b c Guy Chester Shortridge and Donald Carter: A new genus and new species and subspecies of mammals from Little Namaqualand and the North-West Cape Province; and a new subspecies of Gerbillus paeba from the Eastern Cape Province. Annals of the South African Museum 32, 1938, pp. 281–291 ( [2] )
  4. ^ A b c d e Gary N. Bronner: Cryptochloris zyli Van Zyl's Golden-mole. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 251-252
  5. ^ A b c d e Gary N. Bronner and Nigel C. Bennett: Cryptochloris zyli Shortridge & Carter, 1938. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, p. 6
  6. ^ A b c William A. Taylor, Samantha Mynhardt and Sarita Maree: Chrysochloridae (Golden moles). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, pp. 180–203 (p. 202) ISBN 978-84-16728-08-4
  7. ^ A b c Gary N. Bronner: Cryptochloris zyli. The IUCN Red List of Threatened Species 2015. e.T5749A21286235 ( [3] ); last accessed on February 28, 2016
  8. ^ A b c Alberto M. Simonetta: A new golden mole from Somalia with an appendix on the taxonomy of the family Chrysochloridae (Mammalia, Insectivora). Monitore Zoologico Italiano NS Supplement 2, 1968, pp. 27-55
  9. ^ Robert J Asher, Sarita Maree, Gary Bronner, Nigel C Bennett, Paulette Bloomer, Paul Czechowski, Matthias Meyer and Michael Hofreiter: A phylogenetic estimate for golden moles (Mammalia, Afrotheria, Chrysochloridae). MC Evolutionary Biology 10, 2010, p. 69 doi : 10.1186 / 1471-2148-10-69
  10. ^ Gary N. Bronner: Family Chrysochloridae Golden-moles. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume I. Introductory Chapters and Afrotheria. Bloomsbury, London, 2013, pp. 223-225
  11. ^ A b F. Petter: Remarques sur la systematique des Chrysochlorides. Mammalia 45 (1), 1981, pp. 49-53
  12. ^ Gary Bronner: An imminent updated (2017) taxonomy for golden moles. Afrotherian Conservation 14, 2018, pp. 57–59
  13. ^ Galen B. Rathbun: Eponyms in the Afrotheria: Who were the people that had Afrotheria species named after them? Afrotherian Conservation 9, 2012, pp. 5-6
  14. ↑ KM Helgen and DE Wilson: Additional material of the enigmatic golden mole Cryptochloris zyli, with notes on the genus Cryptochloris (Mammalia: Chrysochloridae). African Zoology 36 (1), 2001, pp. 110-112

Web links

Commons : Van Zyls Goldmull ( Cryptochloris zyli )  - Collection of images, videos and audio files