Congo gold mole
| Congo gold mole | ||||||||||||
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Congo gold mole ( Huetia leucorhina ) (drawing from the first description by Joseph Huet, 1885) |
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| Huetia leucorhina | ||||||||||||
| ( Huet , 1885) |
The Congo gold mole ( Huetia leucorhina ; partly also Calcochloris leucorhina or Calcochloris leucorhinus ) is a species of mammal from the family of the gold mole (Chrysochloridae). It is endemic to central Africa , where it has only been found in around a dozen locations in the Congo Basin . The animals inhabit tropical rainforests and transition zones to open savannah landscapes of the lowlands and mountains. Due to their rather graceful physique, they prefer soft floors. There they pursue a soil-digging way of life, for which they, like the other gold mole, are equipped with a spindle-shaped body, which lacks externally visible ears and a tail. They also have strong grave claws on their front feet. However, no information is available about the further behavior of the Congo gold mole. It was scientifically introduced in 1885 , and for a long time its exact systematic position had only been unsatisfactorily clarified. The inventory cannot be assigned to a specific threat category due to insufficient data.
features
Habitus
The Congo gold mole is a small representative of the gold mole . He has a head-torso length of 6.3 to 12.6 cm, weight information is not available. Also, no information about a possibly occurring sexual dimorphism is possible, since too few individuals have been examined so far. The physique is reminiscent of that of the moles , with which the Congo gold mole is not related. Like the other gold mole, it is adapted to a digging way of life. The body accordingly has a spindle shape, which lacks externally visible ears and a tail. The eyes are hidden under the fur, and a leather-like padding is formed on the nose that is used when digging. The back fur has a dark brown to slate gray color, the peritoneum is similar, but more pale in color. The hair is fine and around 7 mm long. A creamy-white colored mask is formed on the face, which extends laterally to the ear openings. The limbs are short and strong, the hands have four, the feet have five rays, each with claws. The claws of the forefoot in particular function as digging tools, but they have a comparatively slim design. The claw of the central ray (III) is the largest and reaches a total length of 9 to 11.5 mm and a basal width of 2.5 to 3 mm. The rear foot length is 9 to 10 mm.
Skull and dentition features
The largest skull length varies between 19.5 and 23.1 mm, the largest skull width between 16.6 and 20.4 mm. Overall, the skull is shaped rather short and wide, the greatest skull width that is reached in the area of the brain skull is more than 70% of the skull length. Likewise, the palate becomes significantly wider with a width of over 30% of the length of the skull. The zygomatic arch is completely closed, but it lacks the wide, backward-facing plates, which are formed among other things in the Giant Goldmullen ( Chrysospalax ). In contrast to numerous other representatives of the golden mole, the hammer of the middle ear does not show any significant enlargements, its weight is 0.63 to 0.77 mg. As a result, no additional bulges are formed on the temporal bone , as is the case with the Cape golden mole rat ( Chrysochloris asiatica ). The dentition consists of 40 teeth, the dental formula is: . The rearmost upper (third) molar usually occurs and with its three-humped ( tricuspid ) chewing surface pattern resembles the other molars. The anterior premolar is completely molarized and thus resembles the posterior molars. A well-developed talonid is largely missing 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 length of the upper row of teeth from the canine to the third molar is 4.7 to 6.5 mm.
distribution
The Congo gold mole is endemic to Africa , as one of the few members of the family it is native to the central part of the continent. He is known from around a dozen localities, some of which are widely scattered. A relatively contiguous area lies in the Congo Basin and includes the southeastern part of Cameroon , the northern part of the Republic of the Congo and the southwestern part of the Central African Republic . More distant sites are in the south of the Democratic Republic of the Congo and in the north of Angola . A record of the species on the Batéké plateau in Gabon about 350 km south of the main distribution area was made in 2005. The animals mainly inhabit the areas of the tropical rainforest of the flat and mountainous regions, but to a limited extent also occur in forest savannahs. Mosaic landscapes in the northern and southern border areas to the closed rainforest areas. They prefer sandy to soft loamy soils. Occasionally they can be seen in cultivated landscapes or in grazing areas.
Way of life
No information is available about the way of life of the Congo gold mole, apart from the soil-digging activities typical of the gold mole.
Systematics
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Internal systematics of the gold mole according to Asher et al. 2010
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The Congo gold mole rat is a species from the genus Huetia . Within the genus, the Somalia gold mole ( Huetia tytonis ) is put to the side. The genus in turn belongs to the family of the golden mole (Chrysochloridae), which summarizes smaller, soil-digging mammals from the parentage of the Afrotheria . Their closest relatives form the Tenreks (Tenrecidae), both families together form the Afrosoricida . Molecular genetic studies show that the separation of the gold mulle and the tenreks from a common lineage occurred in the transition from the Upper Cretaceous to the Paleocene around 65 million years ago. Greater diversification of the gold mole began in the course of the Oligocene about 28.5 million years ago.
The golden mole are endemic in Africa with a focus on the southern continental area, only a few species, including the Congo golden mole, also inhabit parts of eastern or central Africa. Their subterranean way of life means that the individual representatives are habitat specialists , so that the respective occurrence of a species has narrow boundaries; members of the family are more common only in a few exceptions. However, two ecological groups can be distinguished within the family. The first group formed from residents of dry to partly semi-desert landscapes, as the Grant's golden mole ( Eremitalpa ) or chrysochloris ( Chrysochloris ). The second group includes forms that are adapted to open grass and savannah landscapes as well as forests, for example the copper gold mole ( Amblyomus ), the representatives of the genus Neamblysomus, the giant gold mole ( Chrysospalax ) or the Congo gold mole. The internal structure of the family has not yet been satisfactorily clarified. Often two or three subfamilies are differentiated based on the construction of the hammer in the middle ear : 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. Other authors, however, see the latter two as a single subfamily, the Chrysochlorinae. This subdivision of the gold mole, based on skeletal anatomy, has not yet been fully comprehensible through molecular genetic studies. According to these, Huetia has a closer relationship to Cryptochloris and Chrysochloris , which are assigned to the Chrysochlorinae due to their elongated malleus, whereas the non-enlarged hammer of the middle ear in the Congo gold mole has so far advocated integration into the Amblysominae. A preliminary study from 2018 therefore supports a position of Huetia in its own subfamily, the Huetinae.
Two subspecies of the Congo gold mole are known, but their validity is controversial:
- H. l. cahni Schwarz & Mertens , 1922; in Cameroon , the Republic of the Congo and the Central African Republic ; Talonids poorly developed on the anterior premolars, but absent on the last premolars and the last molar; usually a slightly lighter variant.
- H. l. leucorhina Huet , 1885; Democratic Republic of the Congo and Angola ; lower premolars with well-developed talonids.
Animals from northern Angola and the Congo Basin differ in terms of their ossicular morphology . The head of the hammer in examined individuals from the latter region is more distended and larger than in those from the former. There are also individual differences in other anatomical features, such as the size of the footplate of the stapes . This is possibly an indication of a further subspecies differentiation of the Congo gold mole rat.
The first scientific description of the Congo gold mole was created by Joseph Huet in 1885, he referred it to the Cape gold mole with the name Chrysochloris leucorhina . He had two copies from the coastal region of the Gulf of Guinea , which the Museum national d'histoire naturelle in Paris had purchased from an explorer in 1883. The area is considered a type region of the species. With the listing of the species, Huet was able to prove that the gold mole is also native to the more northern, tropical zones of Africa, previously they were only known from the more southern continental areas. One of the specimens was prepared, the other, an 11 cm long animal, kept in alcohol , this serves as the holotype of the species. Huet gave the species name leucorhina due to the light color of the animals' front face ( Greek λευκός ( leukos ) for "white") and ῥίς ( rhis ) for "nose", genitive rhina ). The type specimen of the subspecies H. l. cahni was caught in January 1911 during the Second German Inner Africa Expedition on the Dja River in southeastern Cameroon and comprises a 9.3 cm long female individual of a rather pale brown color; it received its scientific introduction eleven years later by Ernst Schwarz and Robert Mertens .
The systematic status of the Congo gold mole has been assessed differently and controversially discussed in the past. In the 1930s it was still considered a representative of the cape gold mulle based on tooth characteristics, in the course of the 1960s to 1980s some scientists classified it with reference to the normally built hammer of the middle ear in the copper gold mole or saw it within the upper third molar because of the developed upper third molar Genus Chlorotalpa . Morphometric examinations of the skull in the 1990s advocated a provisional inclusion of the Congo gold mole together with the Somalia gold mole in the genus Calcochloris , which also includes the yellow gold mole ( Calcochloris obtusirostris ). The previously mentioned, non-enlarged head of the hammer and the principally wide skull with the likewise quite wide rostrum proved to be consistent with the yellow gold mole . Within the genus Calcochloris , the Congo gold mole was listed in its own subgenus Huetia , which was due to the higher number of teeth compared to the yellow gold mole. Molecular genetic analyzes by Robert J Asher and research colleagues from 2010 showed that the Congo gold mole is not related to the other representatives of the genus Calcochloris , nor did it reveal any relationship to the copper gold mole or the members of Chlorotalpa . Rather, according to these studies, it is relatively basal in a group consisting of the desert gold mole, the cape gold mole and the genus Cryptochloris . For this reason Huetia was raised to the level of a genus by Asher and colleagues and the Congo gold mole was assigned to it as the only representative. Huetia was originally established by Lothar Forcart in 1942 for the Congo gold mole as a subgenus of Chrysochloris . In Forcart's opinion , Huetia differed from Chrysochloris in the lack of a vesicular enlargement of the posterior part of the temporal fossa (which in the Cape Gold Mulles arises from the extension of the head of the malleus). Forcart named the subgenus at that time in honor of Joseph Huet.
Threat and protection
To date, little information is available about the Congo gold mole itself and the threat to its stocks. The main distribution area is in the lowland and mountain rainforest of Central Africa and the northern transition zones to the more open savannah landscape. The region is affected by massive deforestation, which is associated with the creation and expansion of plantations and the associated infrastructure. It is also promoted through the extraction of timber or illegal logging. The resulting landscape destruction also affects the soil to which the animals are bound. A comparable threat scenario can also be assumed for the isolated deposits further south. The IUCN currently leads the way not because the few available information in a risk category, but under "insufficient data basis" ( data deficient ). In order to protect the Congo gold mole, investigations into the actual distribution of the animals and the two subspecies are particularly necessary. In the main distribution area to the north, some stocks are located within protected areas, for example in the Djia Minkebe Odzala National Park and the Sangha Tri National Park , the latter spanning parts of the border area of Cameroon, the Republic of the Congo and the Central African Republic. In Gabon, the Congo gold mole was found in the Batéké National Park in the east of the country; it is unclear whether the more southern populations in the Democratic Republic of the Congo occur in protected areas.
literature
- Gary N. Bronner: Calcochloris leucorhinus Congo 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. 234-235
- 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. 198) ISBN 978-84-16728-08-4
Individual evidence
- ↑ a b c Joseph Huet: Espèce nouvelle de Chrysochloridae de la Côte du Golfe de Guinée. Nouvelles archives du Muséum d'histoire naturelle 8, 1885, pp. 1–15 ( [1] )
- ^ A b c d e f Gary N. Bronner: Calcochloris leucorhinus Congo 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. 234-235
- ^ A b c d e 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. 198) ISBN 978-84-16728-08-4
- ^ A b Matthew J. Mason, Nigel C. Bennett, and Martin Pickford: The middle and inner ears of the Palaeogene golden mole Namachloris: A comparison with extant species. Journal of Morphology 279 (3), 2018, pp. 375-395 doi: 10.1002 / jmor.20779
- ^ A b Andrew C. Kitchener, Fiona Maisels, Liz Pearson and Paul Aczel: A golden mole (Family Chrysochloridae) from savanna woodland in the Batéké Plateau, Gabon. Afrotherian Conservation 6, 2008, pp. 5-6
- ↑ a b S. Maree: Huetia leucorhina. The IUCN Red List of Threatened Species 2015. e.T40597A21288887 ( [2] ); last accessed on January 17, 2016
- ↑ a b c 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
- 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
- ↑ 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
- ^ 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
- ^ A b 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
- ^ Gary N. Bronner and Nigel C. Bennett: Order Afrosoricida. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 1-21
- ^ 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
- ^ Gary Bronner: An imminent updated (2017) taxonomy for golden moles. Afrotherian Conservation 14, 2018, pp. 57–59
- ↑ Ernst Schwarz and Robert Mertens: A new Chrysochloris from South Cameroon. Senkenbergiana 4, 1922, pp. 151–152 ( [3] )
- ^ F. Petter: Remarques sur la systematique des Chrysochlorides. Mammalia 45 (1), 1981, pp. 49-53
- ^ A b Gary N. Bronner: Systematic revision of the Golden mole genera Amblysomus, Chlorotalpa and Calcochloris (Insectivora, Chrysochloromorpha, Chrysochloridae). University of Natal, Pretoria, 1995, pp. 1-346
- ↑ Don E. Wilson, DeeAnn M. Reeder (Ed.): Mammal Species of the World . 3rd edition. The Johns Hopkins University Press, Baltimore 2005, ISBN 0-8018-8221-4 ( [4] )
- ^ L. Forcart: Contributions to the knowledge of the insectivore family Chrysochloridae. Revue suisse de zoologie 49, 1942, pp. 1–6 ( [5] )
Web links
- Huetia leucorhina in the endangered Red List species the IUCN 2014 Posted by: S. Maree, 2014. Accessed on 17/01/2016.
- Goldmulle at the Afrotheria Specialist Group