Cryptochloris

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Cryptochloris
Systematics
Subclass : Higher mammals (Eutheria)
Superordinate : Afrotheria
without rank: Afroinsectiphilia
Order : Tenrecus (Afrosoricida)
Family : Gold mole (Chrysochloridae)
Genre : Cryptochloris
Scientific name
Cryptochloris
Shortridge & Carter , 1938

Cryptochloris is a genus of mammals fromthe golden mole family (Chrysochloridae). With De Winton's gold mole and Van Zyl's gold mole, it comprisestwo species thatare widespreadin western South Africa, but have so far only been detected in very few localities. Both types are therefore extremely rare. Their habitat consists of sandy, very dry landscapes. With their rather diamond-shaped body, which lacks externally visible ears and a tail, as well as their strong forelegs with three well-developed grave claws, they are, like the other gold mole, adapted to an underground way of life. They dig near the surface, but unstable due to the loose soil material. More details about their behavior are rarely available due to the rare sightings. The genus was scientifically introduced in 1938. Their two representatives are endangered in their existence.

features

Habitus

The two species of the genus Cryptochloris represent very small representatives of the golden mole . They are about the same size and reach a head-to-trunk length of 8.2 to 9.2 cm, information on weight is not available. Like all gold moles , the animals are physically similar to the moles , but they are not related to them. The body shows adaptations to a digging way of life, it is diamond-shaped and thus differs somewhat from the spindle-shaped construction plan of the other gold mole. As with these, however, externally visible ears and a tail are missing. The limbs are sturdy, with four front ends and five rear ends. The forelimbs are transformed into grave claws, the claw of the central ray (ray III) is extremely long. On the other hand, the claws of the two inner rays (rays I and II) are somewhat shorter, but are of the same length to each other, which is a striking difference to other gold bullets. The same applies to the fourth ray, whose claw is mostly short but clearly developed, which is not quite as distinctive as that of the desert gold mole ( Eremitalpa granti ). Another peculiarity can be found on the inside of the forefoot, which is broadened in an arc shape by a leathery padding, possibly supported by a sesame bone . A comparable formation also occurs with the moles and is obviously used for digging. The eyes remain hidden under the fur and a leathery padding appears on the nose, which is also used when digging. The fur is colored from lead to slate gray and can have a metallic sheen in sunlight, which in Van Zyl's golden mole ( Cryptochloris zyli ) tends to appear violet, in De Winton's golden mole ( Cryptochloris wintoni ) it appears rather silvery.

Skull and dentition features

The greatest length of the skull varies from 21.3 to 22.3 mm, the greatest width from 15.0 to 16.2 mm. It has a short and wide shape, the greatest width is 70 to 76% of the greatest length. The rostrum is also noticeably wide with a palate width of 35 to 37% of the length of the skull, but somewhat narrower than the desert gold mole. The noticeable thickening of the brain skull in the area of ​​the olfactory bulb , which means that the forehead line is more arched here than with other gold mullets with their rather flat forehead profile. The zygomatic arches are completely closed, but they lack the plate-like appendages pointing backwards like those found in the Giant Goldmullen ( Chrysospalax ). A bony bulge can be seen at the temporal fossa that accommodates the head of the hammer of the middle ear . This is markedly enlarged, in De Winton's Goldmull bloated, in Van Zyl's Goldmull it is lengthened like a club. However, the enlargements do not reach the enormous proportions of the desert gold mole or the closely related cape gold mole ( Chrysochloris ). The dentition consists of 40 teeth together and has the following dental formula : . The two rear, upper incisors and the canine in Cryptochloris are all the same size, while in Cape Goldmulls the second incisor is longer than the third. The third molar is much smaller than the two anterior ones, but like these has a tricuspid chewing surface pattern. There is no well-defined talonid on the lower molars (a deep protrusion of the chewing surface into which one of the main cusps of the upper molars engages when the bite is closed). The entire upper row of teeth from the canine to the last molar reaches a length of about 8 mm.

distribution

The genus Cryptochloris is endemic to Africa . The two species are distributed over a few known localities in Namaqualand on the west coast of South Africa , De Winton's gold mole is only occupied by the type locality near Port Nolloth in the North Cape province , Van Zyl's gold mole has so far been detected at two places that are around 150 km apart and are located in the provinces of North Cape and Western Cape . The animals inhabit deserts and other dry habitats in the Namib and Karoo , they prefer dune landscapes and adjacent sand areas behind them. In both distribution areas occurs sympatric of Grant's golden mole on. Both De Winton's and van Zyl's Goldmull have only rarely been observed, and the documented sightings are accordingly limited to a few individuals.

Way of life

Almost no information is available about the way of life of the two Cryptochloris species. They dig passages close to the surface, some of which lead through the roots of bushes. The loose sand of their habitat usually causes the corridors to collapse very quickly, so that they can be recognized as linear structures on the ground. The main diet consists of invertebrates such as insects , but occasionally smaller vertebrates such as the African blind skink ( Typhlosaurus ), a legless representative of the skink , are consumed.

Systematics

Internal systematics of the gold mole according to Asher et al. 2010
 Chrysochloridae  




 Eremitalpa


   

 Huetia


   

 Cryptochloris


   

 Chrysochloris





   

 Chrysospalax



   

 Calcochloris



   

 Chlorotalpa


   


 Carpitalpa


   

 Neamblysomus



   

 Amblysomus



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Cryptochloris is a genus within the family of the golden moles (Chrysochloridae) and the superiority of the Afrotheria . The golden mole comprise smaller, soil-digging mammals with an endemic distribution in Africa . The majority of the species occurs in the southern part of the continent, while a few inhabit the eastern and central parts. Their closest relatives are the Tenreks (Tenrecidae), which are also common in Africa ; both together form the order of the Afrosoricida . Molecular genetic studies suggest a separation of the gold mole from the Tenreks in the transition from the Upper Cretaceous to the Paleocene around 65 million years ago; the greater diversification of the gold mole took place from the Oligocene around 28.5 million years ago.

According to their subterranean way of life, the golden mole are considered habitat specialists , which means that the occurrence of numerous species is clearly limited locally. Two ecological groups can be distinguished within the family. The first consists of species with an adaptation to dry to some semi-desert regions, this includes the Grant's golden mole ( Eremitalpa ) which chrysochloris ( Chrysochloris ) and the species of the genus cryptochloris . In the second group are representatives of the open grass and savannah landscapes as well as the forests, such as the copper gold mole ( Amblysomus ), Arends' gold mole ( Carpitalpa ), the members of Neamblysomus or the giant gold mole ( Chrysospalax ). The internal structure of the family has not yet been conclusively clarified. For anatomical reasons, the design of the hammer in the middle ear advocates a division into two or three subfamilies: the Amblysominae with a normally built malleus, the Chrysochlorinae with a greatly elongated head of the malleus, and the Eremitalpinae with a spherically inflated head of the malleus. According to some scientists, the latter two also form a subfamily, the Chrysochlorinae. Molecular genetic analyzes do not fully support this subdivision of the gold mole based on differences in skeletal anatomy. According to this, Cryptochloris forms a common group with the desert gold mole , the genus Huetia and the cape gold mole, whereby all forms except Huetia have an enlarged head of the malleus and thus belong to the Chrysochlorinae. The sister form of Cryptochloris are the Cape Gold Mulle, which can also be demonstrated anatomically by the partly club-shaped head of the hammer, which, however , is less developed in Cryptochloris than in Chrysochloris . The genetic and anatomical findings, which are consistent in this case, suggest that this feature only arose once within the gold mole. In addition to the size of the malleus head, separating features are the stronger development of the first claw of the forefoot, the distinctive bulge of the skull and some special tooth features in Cryptochloris compared to Chrysochloris . Due to the great similarities, both genera were temporarily called Chrysochloris in the 1950s and 1960s united, but both have been considered independent of each other since the 1970s. More recent genetic studies may suggest that Cryptochloris is only to be understood as a subgenus within Chrysochloris , which also favors a preliminary study from 2018.

There are two types:

In the 1950s and 1960s, Van Zyls Goldmull was considered a subspecies of De Winton's Goldmull, but has been classified as independent again since the early 1970s. Both types can be distinguished by the color of the fur, the special design of the hammer in the middle ear (inflated in De Winton's Goldmull, club-like in Van Zyl's Goldmull) and the morphology of the forefeet.

The first scientific description of the genus Cryptochloris was in 1938 by Guy Chester Shortridge & T. Donald Carter . They defined the genus on the basis of the shortened, diamond-shaped body, the stronger development of the three main claws on the forefoot, the formation of 40 teeth in the dentition and the more pronounced bulge of the skull in the area of ​​the olfactory bulb . Later, in 1946, Robert Broom added the unusual design of the forefoot with the lateral thickening to this list of features. Along with the genus, Shortridge and Carter also introduced Van Zyl's Goldmull, which they identified as the nominate form , and they put De Winton's Goldmull at his side. This had been established more than 30 years earlier by Broom under the name Chrysochloris wintoni and thus within the Cape Gold Mulle.

Threat and protection

The habitat of the two gold mole species is endangered by the mining of diamonds in the coastal sand, and also by regional infrastructure measures. In addition, the animals are very rare and limited to only a few localities. The IUCN sees De Winton's golden mole as "threatened with extinction" ( critically endangered () to Van Zyl Goldmull as "critically endangered" endangered ). The latter species is represented in the Namaqua National Park , the stock of the former is not present in a protected area.

literature

  • Gary N. Bronner: Genus Cryptochloris 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. 250-252
  • Gary N. Bronner and Nigel C. Bennett: Genus Cryptochloris Shortridge & Carter, 1938. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 5-6
  • Ronald M. Nowak: Walker's Mammals of the World . The Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9
  • 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 ISBN 978-84-16728-08-4

Individual evidence

  1. ↑ a b Robert Broom: Some new and some rare Golden moles. Annals of the Transvaal Museum 20, 1946, pp. 329-335
  2. ↑ a b c K. M. 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
  3. ↑ a b c d e f g Gary N. Bronner: Genus Cryptochloris 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. 250-252
  4. ↑ a b c d e f g h Gary N. Bronner and Nigel C. Bennett: Genus Cryptochloris Shortridge & Carter, 1938. In: John D. Skinner and Christian T. Chimimba (eds.): The Mammals of the Southern African Subregion . Cambridge University Press, 2005, pp. 5-6
  5. ^ A b Robert Broom: On some new species of Chrysochloris. The Annals and magazine of natural history 7 (19), 1907, pp. 262–268 ( [1] )
  6. ^ A b c Gary N. Bronner: Cryptochloris wintoni. The IUCN Red List of Threatened Species 2015. e.T5748A21287143 ( [2] ); last accessed on March 5, 2016
  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 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
  9. Jump up ↑ Robert W. Meredith, Jan E. Janečka, John Gatesy, Oliver A. Ryder, Colleen A. Fisher, Emma C. Teeling, Alisha Goodbla, Eduardo Eizirik, Taiz LL Simão, Tanja Stadler, Daniel L. Rabosky, Rodney L. Honeycutt, John J. Flynn, Colleen M. Ingram, Cynthia Steiner, Tiffani L. Williams, Terence J. Robinson, Angela Burk-Herrick, Michael Westerman, Nadia A. Ayoub, Mark S. Springer, and William J. Murphy: Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification. Science 334, 2011, pp. 521-524
  10. ↑ C. Gilbert, PC O'Brien, G. Bronner, F. Yang, A. Hassanin, MA Ferguson-Smith and TJ Robinson: Chromosome painting and molecular dating indicate a low rate of chromosomal evolution in golden moles (Mammalia, Chrysochloridae) . Chromosome Research 14, 2006, pp. 793-803
  11. ^ Gary N. Bronner: Order Afrosoricida Tenrecs, Otter-Shrews, 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. 214-215
  12. ^ 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
  13. ^ 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
  14. ^ A b F. Petter: Remarques sur la systematique des Chrysochlorides. Mammalia 45 (1), 1981, pp. 49-53
  15. ^ Gary Bronner: An imminent updated (2017) taxonomy for golden moles. Afrotherian Conservation 14, 2018, pp. 57–59
  16. ^ 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 ISBN 978-84-16728-08-4
  17. ↑ a b 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 ( [4] )
  18. ^ Robert Broom: A contribution to the knowledge of the cape golden moles. Transactions of the South African Philosophical Society 18, 1907, pp. 283-311 ( [5] )

Web links

Commons : Cryptochloris  - collection of images, videos and audio files