Zanzibar duiker
| Zanzibar duiker | ||||||||||||
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| Scientific name | ||||||||||||
| Cephalophus adersi | ||||||||||||
| Thomas , 1918 |
The Zanzibar duiker ( Cephalophus adersi ), also vein Ducker called, is a small species of duiker that a highly limited distribution area in the east of Africa inhabited. It occurs on the island of Zanzibar and in individual forest areas along the coast of Kenya . Outwardly characteristic are the red coat color and the white stripe on the abdomen. The way of life of the Zanzibar ducker has so far been little researched. It lives diurnal and solitary, its food consists mainly of soft vegetable food. The species is threatened with extinction from hunting and habitat destruction. A previously unknown population was discovered in northeast Kenya in 2010.
features
Habitus
The Zanzibar duiker is a rather small representative of the duiker and reaches a head-torso length of 63 to 78 cm plus a short tail measuring only 6 to 13.8 cm. The shoulder height is 37.4 to 44 cm, the weight is 6.8 to 12 kg. With an average body weight of 9.2 kg, males are only slightly heavier than females with around 9 kg. The fur is generally soft and shiny, the basic color of the back consists of a tan red or ocher brown, which is somewhat darker on the trunk. At the neck it turns into a more or less distinct gray. On the other hand, the base tone brightens on the sides, while the belly and the inner legs appear whitish. The outsides of the legs, on the other hand, are also reddish with a darker shade towards the hooves, with the exception of a light white stripe on the rear trunk, which goes over to the rear legs. The Zanzibar duiker differs from other red duikers in that it has white spots on its lower legs. The rear foot measures 19.5 to 22.5 cm. The tail is tan, but shows a white tuft of hair at the end. The head is dominated by a gray-light brown color with a distinctly red forehead. The ears are on average 7.8 cm long. The horns are only very short overall, in males 3.5 to 5.3 cm, in females 1.4 to 3.5 cm. Between the horns there is a distinctly red tuft of 4 cm long hair that sometimes covers the horns.
Skull features
The fore-eye pit is very deep and has a sharp upper edge. The frontal bone is less bulging, while the nasal bone increases in width towards the back. The dental formula is: . Thus a total of 32 teeth are formed.
distribution
The Zanzibar duiker is widespread on the east coast of Africa and on the offshore island of Zanzibar . On Zanzibar, a total of five more or less separate populations have been recorded in the Kiwengwa forest in the north, near the Jozani Chakwa Bay National Park in the center and near Mtende in the south of the island. On the African mainland, the duiker species once occurred along the Kenyan coast from Mombasa to the north of the border with Somalia . Today it can only be found in individual spots, for example in the 420 km² Arabuko Sokoke Forest south of the Tana . After a brief sighting around 2004, a previously unknown population was rediscovered around six years later in the Boni and Dodori national reserve north of the Tana. This approximately 3000 km² natural area consists of a mosaic landscape of forests, thickets and savannas . The species prefers undisturbed, closed coastal forests and thickets on coral limestone with heights of growth from 3 m, but with an open shelter. In the Arabuko Sokoke Forest , it is very common in areas with cynometra growth on red soils. The individual density is given here as 2.8 animals per square kilometer. On Zanzibar it is on average about 4.5 animals per square kilometer, but it can increase locally to 11.4 animals. In the recently discovered population in the Boni-Dodori forest system, the individual density was determined according to studies on about 7.3 animals on a comparably large area. In the vast majority of its distribution area, the Zanzibar duiker occurs sympatricly with the Harvey red duiker ( Cephalophus harveyi ), the blue duiker ( Philantomba monticola ) and the muskbuck ( Nesotragus moschatus ). Individual small groups of the Zanzibar duckers were also settled on the surrounding islands of Zanzibar, for example on Tumbatu , Chumbe and Mnemba .
Way of life
The Zanzibar duiker is active during the day with activity times from dawn to dusk, and mostly rests between 11:00 a.m. and 3:00 p.m. It usually occurs individually, but has also been spotted in groups of two or three individuals. As a territorial animal, it actively defends its territory. The Zanzibar duiker marks the boundaries of the territory with the help of its small pre-eye glands, whereby it sets the scent marks on protruding branches. Piles of dung may have the same function. The animals are always alerted and have an excellent sense of smell and hearing.
The main food consists of fallen fruit, leaves , flowers , seeds , buds and sprouts . Partial the Zanzibar Ducker follows the groups of Weißkehl monkeys and Zanzibar Colobus and feeds on the dropped from the monkeys plant material. A single gastric remnant investigated so far contained fruits of Tetracella , ebony trees and figs , animals were also observed eating parts of Mystroxylon , Polyspheria , Euclea and Canthium . They take in water through their food.
Little is known about reproduction, it takes place all year round. Pregnant females have been found from June to November, a suckling female in December.
Systematics
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Internal classification of the genus Cephalophus according to Johnston et al. 2012
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The Zanzibar duiker is a species from the genus Cephalophus and the horned bearer family (Bovidae). Within the horn-bearers, Cephalophus belongs to the tribe of duikers (Cephalophini), which contain two other genera with Sylvicapra and Philantomba . The duikers are mostly small to medium-sized, compactly built representatives of the horned bearers, which are endemic to Africa . They are mainly adapted to wooded habitats , exceptions are the members of Sylvicapra who inhabit savannah landscapes .
The genus Cephalophus is the most species-rich group within the duiker, molecular genetic studies from 2001 showed that the genus can be split into three lines of development. These include the giant Ducker to the Jentink-Ducker ( Cephalophus jentinki ) and the bay duiker ( Cephalophus dorsalis ), the West African red duiker as the Peter Drucker ( Cephalophus callipygus ) and Ogilby-Ducker ( Cephalophus ogilbyi ) and the East African red duiker, such as the Natal-red duiker ( Cephalophus natalensis ) and the black forehead duiker ( Cephalophus nigrifrons ). In principle, this classification of the genus Cephalophus was also confirmed by later studies published in 2012. However, they also showed that neither the Zanzibar duiker nor the zebra duiker ( Cephalophus zebra ) can be precisely assigned to one of these three groups. In addition, Sylvicapra turned out to be the sister group of giant duikers, which makes the genus Cephalophus paraphyletic . Perhaps the red duiker in need by Cephalophus are released, it was suggested Cephalophorus as a generic name for this. For this reason, a new generic name, Leucocephalophus, has also been proposed for the Zanzibar duiker .
It is generally assumed that the small duikers within the genus Cephalophus represent the more primitive forms and that the larger ones are derived from them. The separation of the Zanzibar duckers from the line of ancestors began around 5.25 million years ago according to molecular genetic studies in the transition from the Miocene to the Pliocene . The numerous species of red duiker may later emerged from this early split. The today fragmented occurrence of the Zanzibar duiker on the east coast of Africa and in the peripheral area to the other representatives of the genus Cephalophus is possibly a relic of the geological past, once far greater distribution of the ancestral form of the red duiker. Fossil finds of the Zanzibar ducker are not known.
The Zanzibar duiker is monotypical , no subspecies are distinguished. The first scientific description was carried out by Oldfield Thomas in 1918. For this he had an individual at his disposal who had been given to him by Walter Mansfield Aders, a former state biologist on Zanzibar, together with other ungulates and which originally came from the island of Zanzibar. In his honor Thomas named the species Cephalophus adersi .
Threat and protection
The population of the Zanzibar ducker is highly endangered. The greatest threats include the deforestation for building and fire materials and the associated loss of habitat, as well as the hunting of animals as a food resource. In both Kenya and Zanzibar, the hunt for the Zanzibar duiker has a long tradition, the meat of which is valued for its sweet taste. The hunt for the 1964 revolution increased sharply on the island. As a result, the population fell from around 5000 individuals in 1982 to around 610 in 1999, a decrease of almost 88% over 17 years. The data come from three studies over the course of this time, the survey methods of which differed from one another, so that they are only partially comparable; more recent surveys are not yet available. In the Arabuko Sokoke National Park on the East African mainland, the Zanzibar duiker is possibly even more threatened, only 500 animals are still suspected in the nature reserve, possibly only 320 to 400. However, the assumption is based on very few sightings between 1999 and 2003. The newly discovered population in the Boni-Dodori forest system may prove to be extremely important for the conservation of the species. The investigations carried out there in 2010 with the help of camera traps at three different locations ( Boni and Dodori National Reserves as well as Boni Forest ) suggest that the Zanzibar Duckers are spreading very continuously in the forests. For an 84 km² strip in the Boni National Reserve, extrapolations resulted in around 600 individuals. Overall, the IUCN classifies the species as " critically endangered " . It is represented in several nature reserves.
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. 769-770
- Andrew Williams: Cephalophus adersi Ader's 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. 248-252
Individual evidence
- ↑ a b c d e f g h Andrew Williams: Cephalophus adersi Ader's 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. 248-252
- ↑ a b c d e f g 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. 769-770
- ↑ Samuel A. Andanje, Andrew E. Bowkett, Bernard Risky Agwanda, Grace W. Ngaruiya, Amy B. Plowman, Tim supervisor and Rajan Ami: A new population of the Critically Endangered Aders' duiker Cephalophus adersi confirmed from northern coastal Kenya. Oryx 45 (3), 2011, pp. 444-447
- ^ Rajan Amin, Galen B. Rathbun and Samuel Andanje: Conservation concerns for Afrotheria in northern coastal Kenya. Afrotherian Conservation 8, 2011, pp. 15-16
- ^ A b Rajan Amin, Samuel A. Andanje, Bernard Ogwonka, Abdullahi H. Ali, Andrew E. Bowkett, Mohamed Omar and Tim Wacher: The northern coastal forests of Kenya are nationally and globally important for the conservation of Aders'duiker Cephalophus adersi and other antelope species. Biodiversity and Conservation 2014 doi : 10.1007 / s10531-014-0842-z
- ^ A b c d 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] )
- ↑ 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
- ↑ 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
- ^ Colin Groves: Current taxonomy and diversity of crown ruminants above the species level. Zitteliana B 32, 2014, pp. 5-14
- ↑ Jonathan Kingdon: Genus Cephalophus Forest Duikers. 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, p. 244
- ↑ Oldfield Thomas: A new duiker from Zanzibar. The Annals and magazine of natural history 9 (2), 1918, pp. 151–152 ( [2] )
- ↑ Derek Finnie: Aders' Duiker (Cephalophus adersi) Species Recovery Plan (Revised). Forestry Technical Paper 124, Department of Commercial Crops, Fruits and Forestry, Zanzibar, 2002 ( [3] )
- ↑ D. Finnie: Cephalophus adersi. The IUCN Red List of Threatened Species. Version 2015.2. ( [4] ); last accessed on July 7, 2015
Web links
- Cephalophus adersi inthe IUCN Red List of Threatened Species 2012.2. Posted by: Finnie, 2008. Retrieved October 23, 2012.