Black forehead thug

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Black forehead thug
Black-forehead duiker (Cephalophus nigrifrons)

Black- forehead duiker ( Cephalophus nigrifrons )

Systematics
without rank: Forehead weapon bearer (Pecora)
Family : Horned Bearers (Bovidae)
Subfamily : Antilopinae
Tribe : Duiker (cephalophini)
Genre : Cephalophus
Type : Black forehead thug
Scientific name
Cephalophus nigrifrons
Gray , 1871

The black- fronted duiker ( Cephalophus nigrifrons ) is a species of duiker from central Africa . It inhabits most of the Congo Basin and occurs in the east as far as the Virunga volcanoes , where it can also be found at very high altitudes. The red coat color and the dark facial markings are characteristic. The species inhabits swampy to moist forests and lives solitary. The food mainly consists of fruits and leaves, only in the higher areas do the animals also consume grass, moss and lichens more frequently. Within the duiker, the black forehead duiker is placed in the group of the East African red duiker; genetic studies show that it is more closely related to the red flank duiker . The species was first described in 1871. The stock is currently classified as not endangered.

features

Habitus

The black-fronted duiker is a medium-sized representative of the duiker, roughly comparable to other red duiker, but equipped with relatively long legs. Its head-trunk length is 85 to 107 cm, the tail is only 10 to 16 cm long. The shoulder height is 53.5 to 57.8 cm, while the weight varies from 13 to 16 kg. A pronounced sexual dimorphism is not pronounced, females weigh on average 14.0 kg, males 13.8 kg. The basic color of the dense fur comprises a deep, shiny chestnut or fox brown, with individual hairs having a brown base and a reddish tip. The sides of the body lighten a little, sometimes the shoulders are a little darker. There is no black median stripe on the back, instead a dark spot or stripe appears on the chest. The tail is the same color as the body, but has a whitish underside in places. It ends in a black tuft of hair interspersed with whitish hair. The limbs are darker and become almost black towards the hooves. In the populations in the western area of ​​distribution, the black coloring is only evident on the front and rear feet, in the case of those in the east it often includes the entire legs. The long and thin hooves are striking, the length of the rear foot varies from 28.1 to 31.0 cm. In general, the head also appears reddish-brown. It is named after the black to dark red markings that stretch from the nose to the forehead and widen behind the eyes; it is partially flanked by a red-brown stripe on each side. The chin continues to stand out with a light reddish color. The ears are also blackish, but have a white spot on the inside. Their length varies from 8.6 to 9.5 cm. A long, dark-colored tuft of hair grows between the ears. The horns consist only of short spikes that slope backwards. They are 6.5 to 9.5 cm long in males (with a record length of 11.5 cm) and 1.3 to 5.2 cm long in females.

Skull features

The skull is narrow overall with a slightly kinked rostrum when viewed from the side so that the nasal bone completely covers the upper jaw when viewed from above. The frontal bone shows significant thickening. The bit has the following dental formula: . A total of 32 teeth are thus formed.

distribution

The distribution area of ​​the black forehead duck includes the Congo Basin in Central Africa . It comes in the north from the Niger Delta in southeastern Nigeria , where the duiker species was only detected in 2002, and from southern Cameroon about south of the Sanaga across the entire basin to Angola in the south and to the Virunga volcanoes between Uganda and Rwanda in the east in front. The habitat in the lowlands consists of swampy forests and marshland or riparian forests. As a result, the species regularly expands its occurrence in the rainy season when dry forest areas are flooded. In the okapi game reserve of the Ituri forest in the northeast of the Democratic Republic of the Congo , the black-fronted duiker can be found in forests that are dominated by gilbertiodendrons in the south and west of the reserve. It also occurs in mixed forests with Cynometra and Julbernardia plant communities in the center and north. The population density is roughly evenly distributed in both areas and varies between 1.1 and 3.0 animals per square kilometer (an average of 1.3 in the first and 2.0 in the last landscape type). In the mountains in the eastern area of ​​distribution, the black-fronted duiker rises up to 3700 m above sea level. Overall, the animals here often prefer forests with open shelters but rich vegetation on herbaceous plants, but there is no adaptation to very moist subsoil in the high mountain areas. In the volcano national park of the Virunga volcanoes, the population density ranges from around 4.7 individuals per square kilometer in the lower-lying, bamboo- covered regions below 3000 meters above sea level to 11.0 to 21.6 animals per square kilometer in the various forests and areas Meadow landscapes between 3200 and 3500 meters above sea level, while in the even higher altitudes of the alpine level of the tropical areas it falls back to 7.1 individuals on a comparably large area. In the Bwindi Impenetrable National Park in southwestern Uganda, the black- fronted duiker is one of the most frequently observed ungulates, here it prefers to be at an average altitude of 2150 m.

Way of life

Territorial behavior

Historical depiction of the black-headed printer from 1894

The black forehead duiker is diurnal and solitary, occasional sightings of pairs go back to mother-young animal groups or encounters between males and females, but the latter could also indicate stable pair formation. The black-forehead duiker often goes to the swamps to feed during the day and returns to the dense forests at night. With its long hooves, it is well adapted to the damp to swampy habitat , and it is also considered a good swimmer and thus crosses rivers and other bodies of water. The animals live territorially and mark their territories with the help of secretions from the pre-eye glands, sometimes they also put dung heaps on the borders. They use paths through dense vegetation within their territories. When running, the tail flips up regularly and shows the white underside. Occasional fights are fought by repetitive head ramming similar to goats and end in flight into the bushes. Often a knocking noise is generated, although it is unclear whether this is actually a vocalization or whether it is produced in some other way. Another sound is a whistle, which also serves as an alarm signal.

nutrition

The food is based in principle on soft vegetable food, but its composition varies depending on the region. In the Ituri forest , according to studies of stomach contents, 29% of it consists of leaves of herbaceous plants, the rest consists of fruits , seeds , flowers and mushrooms , whereby the fruits are more fibrous like those of ricinodendron from the group of the milkweed family . The consumption of the fruits is mostly dependent on the availability of windfalls, among the seeds that of Gilbertiodendron , a carob plant, dominate . According to observations near Makokou in Gabon, fruits predominate here with 71.6%, followed by leaves with 27.8%, the remaining 0.6% include mushrooms, flowers and animal material. The preferred fruits are only 1 to 3 cm in size and are completely eaten. A total of 33 different plant species could be identified in the region, of which the black-forehead duiker consumed fruit, the dominant ones being those of Plagiostyles , Klainedoxa and Ongokea . However, the black forehead duiker is less frugivorous than other duikers in the region. Especially in the rainy season, the proportion of leaves and animal material increases, the latter largely consisting of ants , which an animal actively picks up from the ground. In the mountain regions of the Virunga volcanoes, where fruits are much rarer, leaves and sometimes grasses make up the main food with 80.7%, 14.8% are formed by lichens and mosses and 4.5% are made up of bark . It is assumed that the low content of tannins and alkaloids in the herbs of the mountain regions allows the black-forehead duiker to eat a diet that is very different from its relatives in the lowland regions. The most commonly consumed plants are spring herbs with almost 21%, followed by horn herbs , chickweed , cranesbills , violets and mint . Among the lichens, the duiker favors the tree-growing genus Usnea , in order to reach them it occasionally stands on its hind legs and plucks the food from a great height.

Reproduction

Almost nothing is known about reproduction. Pregnant females were observed in December, lactating females in February and March. The maximum age in human captivity is 17 years.

Predators and enemy behavior

The leopard is one of the most important predators . However, the black forehead duiker in the Ituri forest only accounts for 1.7% of the food in the analyzed feces of the big cat. This is the lowest evidence of all representatives of the duiker living there, based on the relative abundance in the region, and half less than would be expected. When the faeces of the African golden cat were analyzed at the same time , the duiker species could not be proven at all. Possibly the black-forehead duiker escapes a stronger hunt due to its preference for swampy terrain. Defensive behavior includes being rigid, sometimes even in the middle of a step, laying on the ground or sneaking away into dense bushes if the predator has not noticed the animal. In the event of immediate danger, the black-forehead duiker flees with bowed head and often in a zigzag through the vegetation and utters whistling warning calls.

Parasites

Internal parasites include tapeworms as Avitinella and Stilesia and nematodes such as Bunostromum or Dipetalonema . According to studies on animals from the Ituri forest , the black- forehead duiker tends to be more parasitic than other duikers native to the region. The bluetongue virus and leptospira , which cause leptospirosis and can also be transmitted to humans through meat consumption, are important here .

Systematics

Internal classification of the genus Cephalophus according to Johnston et al. 2012
 Cephalophus  

  "Giant duiker"  


 Sylvicapra


   


 Cephalophus silvicultor


   

 Cephalophus spadix



   

 Cephalophus jentinki


   

 Cephalophus dorsalis





   

 Cephalophus zebra



   
  "East African red duiker"  



 Cephalophus rufilatus


   

 Cephalophus nigrifrons



   

 Cephalophus harveyi


   

 Cephalophus natalensis




   

 Cephalophus leucogaster



  "West African red duiker"  

 Cephalophus niger


   

 Cephalophus rubidus


   

 Cephalophus weynsi


   

 Cephalophus callipygus


   

 Cephalophus ogilbyi








   

 Cephalophus adersi



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Historical illustration of the black-forehead printer from the first description by John Edward Gray , 1871

The black forehead duiker is a species from the genus Cephalophus and the family of horned bearers (Bovidae). The genus belongs to the tribe of duikers (Cephalophini) within the horn-bearers , to which two other genera are included with Sylvicapra and Philantomba . The duikers mostly include smaller to medium-sized, compactly built representatives of the horned bearers, which are endemic to Africa . With the exception of the members of Sylvicapra who live in savannah landscapes , they are predominantly adapted to wooded habitats .

Within the duiker, Cephalophus is the most species-rich group. A molecular genetic study from 2001 enabled the individual species of the genus to be assigned a total of three lines of development. These include the giant duiker with the jentink duiker ( Cephalophus jentinki ) and the black- backed duiker ( Cephalophus dorsalis ), as well as the West African red duiker, such as the St. Peter's duiker ( Cephalophus callipygus ) and the ogilby duiker ( Cephalophus ogilbyi ) as well as the East African red duiker Natal red duiker ( Cephalophus natalensis ) and the Harvey red duiker ( Cephalophus harveyi ). In principle, this classification of the genus Cephalophus was also confirmed by later studies published in 2012. Accordingly, the black-forehead duiker belongs to the East African red duiker and is closely related to the red-flanked duiker ( Cephalophus rufilatus ). The splitting of the East African red duiker took place in the transition from the Pliocene to the Pleistocene around 2.4 to 1.2 million years ago. Another result of the genetic investigations was that Sylvicapra represents the sister group of the giant duiker, which makes the genus Cephalophus appear paraphyletic . Therefore possibly the red duiker in need Cephalophus are released, it was suggested Cephalophorus as a generic name for this.

A distinction is made between two subspecies of the black-headed duck:

Originally also were Elgon black-fronted duiker ( Cephalophus forsteri ) from Mount Elgon in Uganda, the Kenyan black-fronted duiker ( Cephalophus hooki ) from Mount Kenya in Kenya , the Itombwe-black-fronted duiker ( Cephalophus hypocxanthus ) from the Itombwe mountains west of Lake Tanganyika and the Ruwenzori -Black-forehead duiker ( Cephalophus rubidus ) from the Ruwenzori Mountains between Uganda and the Democratic Republic of the Congo considered a subspecies. However, a revision of the horn bearers from 2011, which was developed by Colin Peter Groves and Peter Grubb , recognizes this as independent. In the case of the Ruwenzori black-headed duiker, which was sometimes also considered a subspecies of the Natal red duiker, a separate species status was discussed beforehand. The genetic studies also show that it is not closely related to the East African red duiker and belongs to the group of the West African red duiker.

The first scientific description of the black-headed printer was created by John Edward Gray in 1871 . The individual he used for this was in the possession of the Natural History Museum in London, but was originally from Gabon. This region is considered a type area of ​​the species.

Threat and protection

The black forehead duiker is relatively widespread across central Africa. The greatest threat is the destruction of the tropical rainforests and the associated expansion of human settlements and economic areas. Hunting the species for the bushmeat market is also an influential risk factor. It is therefore possible that the number of populations will decline more sharply in the future and that the species will be restricted to isolated groups in protected forest areas. At the moment the IUCN classifies the black- forehead duiker as “not at risk” ( least concern ), but a more significant decrease in the number of individuals would require the status “ near threatened ” (the classification is made together with the Elgon, Kenya, Itombwe - and Ruwenzori black forehead thugs). It occurs in several nature reserves, such as the Lobéké National Park in Cameroon, the Dzanga Sangha Conservation Area in the Central African Republic and the Volcano National Park in Rwanda.

literature

  • Colin P. Groves and David M. Leslie Jr .: Family Bovidae (Hollow-horned Ruminants). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 772-773
  • Andrew J. Plumptre: Cephalophus nigrifrons Black-fronted Duiker. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 268-271

Individual evidence

  1. a b c d e f g h i Andrew J. Plumptre: Cephalophus nigrifrons Black-fronted Duiker. In: Jonathan Kingdon, David Happold, Michael Hoffmann, Thomas Butynski, Meredith Happold and Jan Kalina (eds.): Mammals of Africa Volume VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury, London, 2013, pp. 268-271
  2. a b c d e f g h i Colin P. Groves and David M. Leslie Jr .: Family Bovidae (Hollow-horned Ruminants). In: Don E. Wilson and Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 772-773
  3. CB Powell and Peter Grubb: Range-extension of black-fronted duiker (Cephalophus nigrifrons Gray 1871, Artiodactyla, Bovidae): first records from Nigeria. Tropical Zoology 15, 2002, pp. 89-95
  4. John A. Hart: Diversity and abundance in an African forest ungulate community and implications for conservation. In: William Weber, Lee JT White, Amy Wedder, and Lisa Noughton-Treves (Eds.): African Rain Forest Ecology and Conservation: An Interdisciplinary Perspective. Yale University Press, 2001, pp. 183-206
  5. Andrew J. Plumptre and S. Harris: Estimating the Biomass of Large Mammalian Herbivores in a Tropical Montane Forest: A Method of Faecal Counting That Avoids Assuming a 'Steady State' System. Journal of Applied Ecology 32 (1), 1995, pp. 111-120
  6. Badru Mugerwa, Douglas Sheil, Peter Ssekiranda, Miriam van Heist and Pontious Ezuma: A camera trap assessment of terrestrial vertebrates in Bwindi Impenetrable National Park, Uganda. African Journal of Ecology 51, 2012, pp. 21-31
  7. A. Gautier-Hion, LH Emmons and G. Dubost: A Comparison of the Diets of Three Major Groups of Primary Consumers of Gabon (Primates, Squirrels and Ruminants). Oecologia 45, 1980, pp. 182-189
  8. ^ Gerard Dubost: Comparison of the Diets of Frugivorous Forest Ruminants of Gabon. Journal of Mammalogy 65 (2), 1984, pp. 298-316
  9. Andrew J. Plumptre: The chemical composition of montane plants and its influence on the diet of the large mammalian herbivores in the Parc National des Volcans, Rwanda. Journal of Zoology 235, 1995, pp. 323-337
  10. John A. Hart, M. Katembo and K. Punga: Diet, prey selection and ecological relations of leopard and golden cat in the Ituri forest, Zaire. African Journal of Ecology 34, 1996, pp. 364-379
  11. William B. Karesh, John A. Hart, Terese B. Hart, Carol House, Alfonso Torres, Ellen S. Dierfeld, W. Emmett Braselton, Helena Puche and Robert A. Cook: Health Evaluation of Five Sympatric Duiker species (spp Cephalophus .). Journal of Zoo and Wildlife Medicine 26 (4), 1995, pp. 485-502
  12. a b c d e Anne R Johnston and Nicola M Anthony: A multi-locus species phylogeny of African forest duikers in the subfamily Cephalophinae: evidence for a recent radiation in the Pleistocene. BMC Evolutionary Biology, 12, 2012, p. 120 ( [1] )
  13. a b Bettine Jansen van Vuuren and Terence J. Robinson: Retrieval of Four Adaptive Lineages in Duiker Antelope: Evidence from Mitochondrial DNA Sequences and Fluorescence in Situ Hybridization. Molecular Phylogenetics and Evolution 20 (3), 2001, pp. 409-425
  14. Alexandre Hassanin, Frédéric Delsuc, Anne Ropiquet, Catrin Hammer, Bettine Jansen van Vuuren, Conrad Matthee, Manuel Ruiz-Garcia, François Catzeflis, Veronika Areskoug, Trung Thanh Nguyen and Arnaud Couloux: Pattern and timing of diversification of Cetartiodactalia, Lauriala (Mammia ), as revealed by a comprehensive analysis of mitochondrial genomes. Comptes Rendus Palevol 335, 2012, pp. 32-50
  15. ^ Colin Groves: Current taxonomy and diversity of crown ruminants above the species level. Zitteliana B 32, 2014, pp. 5-14
  16. Colin Groves and Peter Grubb: Ungulate Taxonomy. Johns Hopkins University Press, 2011, pp. 1–317 (SS 108–280)
  17. ^ John Edward Gray: Notes on the bush-bucks (Cephalophoridae) in the British Museum, with the description of two new species from Gaboon. Proceedings of the Zoological Society 1871, pp. 588-601 ( [2] )
  18. ^ IUCN SSC Antelope Specialist Group: Cephalophus nigrifrons. The IUCN Red List of Threatened Species. Version 2015.2. ( [3] ); last accessed on July 12, 2015

Web links

Commons : Black Forehead Ducker ( Cephalophus nigrifrons )  - Collection of images, videos, and audio files