Black-nosed Impala

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Black-nosed Impala
Female black-nosed impala

Female black-nosed impala

Systematics
Subordination : Ruminants (ruminantia)
Family : Horned Bearers (Bovidae)
Subfamily : Antilopinae
Tribe : Aepycerotini
Genre : Impalas ( Aepyceros )
Type : Black-nosed Impala
Scientific name
Aepyceros petersi
Bocage , 1879

The Black-faced Impala ( Aepyceros petersi ) is a species in the genus of impala within the family Bovidae . It occurs in southwest Africa . There she lives in dry savannah areas with bushes and trees. The animals generally stay near bodies of water and sources of drinking water. They are medium-sized antelopes , which, like the closely related black heel antelope , have a graceful build with slender limbs and a straight back as well as distinctive black fur on the hind feet. A striking feature is the black face stripe from the nose up, to which the black-nosed impala owes its common name . Horns are only developed in male individuals. The females and their offspring live in small herds that move around in extensive action areas . During the reproductive phase, the males show territorial behavior. Most of the time, a mother gives birth to a single young, which is initially hidden away from the herd. Both grasses and leaves and other soft plant components serve as food . The respective share varies over the course of the year. The black-nosed impala was scientifically introduced in 1879. For a long time it was only considered a subspecies of the black heel antelope, but genetic studies advocate a separate position. The population is endangered by hunting and spreading pasture areas.

features

Habitus

Male black-nosed impala

The black-nosed impala is a medium-sized representative of the antelope , but on average reaches larger dimensions than its sister species , the black-heeled antelope . A head-trunk length between 124 and 145 cm was measured in around a dozen examined individuals from Namibia . The weight of female animals is around 50.4 kg, that of males around 63 kg. The sexual dimorphism is thus clearly developed. Outwardly, both types of impala are similar, the body is slender and has a straight back line, the legs are long and delicate, the head is straight. The short-haired fur is typically reddish-brown on the head and back, the sides of the body and the outside of the legs are a little lighter. The inside of the legs and the stomach stand out due to their whitish color. Whitish spots also appear on the eyes, mouth and throat. In contrast to the black heel antelope, a black band starts about 2 cm above the nasal surface and extends upwards between the eyes and partly continues as a thin line on the forehead. While the head stripe is not always formed, the face stripe can reach up to 4 cm in width. With a length of 13.0 to 18.5 cm, the ears are larger than those of the black heel antelope and have a broader dark tip. Compared to the black heel antelope, the tail is bushier and, at 30 to 50 cm in length, also on average longer. As with the sister species, a vertical dark stripe on the side of the tail covers one buttock. There are also dark fur markings on the heels , which indicate a gland , the metatarsal gland . Horns are only found in males. They are curved like a lyre and clearly fluted. The longest known horns measure 68 cm and come from an individual from Grootfontein in Namibia.

Skull and dentition features

The skull of the black-nosed impala becomes between 26.1 and 28.6 cm long and on the zygomatic arches between 9.7 and 11.2 cm wide. The dentition consists of 32 teeth with the following dental formula : .

distribution and habitat

Distribution area of ​​the two types of impala:
  • Black heel antelope
  • Black-nosed Impala

    • The black-nosed impala is endemic to southwestern Africa , where it occurs in northwestern Namibia and southwestern Angola . It is separated from the westernmost population of black heel antelope by the approximately 300 km wide Ovamboland . As a result, the black-nosed impala colonizes the area around the Kunene , which touches the edge of the important Etosha pan in Namibia, while the black-heeled antelope reaches its western limit in the Okavango region in Botswana . In detail, the distribution area of ​​the species includes the areas around Otjimborombonga and Swartbooisdrift on the Kunene in the north to the south to the area south and southwest of the Etosha National Park . In Namibia the species is limited to the Kaokoveld . The black-nosed impala uses woodlands, open scrubland and savannahs near the water as preferred habitats . It is often found in mopane , tamboti and acacia plant communities. In the Etosha National Park, 50% of the animals are within 1 km of the nearest water source, the greatest distance is 3.7 km. There is no difference between rainy and dry seasons. In general, the region is characterized by low annual precipitation of only 25 to 400 mm. The population density varies on average between 44.7 individuals per square kilometer in the dry season and almost 16 animals on a comparable area in the rainy season. However, considerable variations can occur in the various landscape areas used. The density of individuals in the Tamboti areas is around 208 in the dry season and only 2.7 animals per square kilometer in the rainy season. In bush landscapes on granite subsoil , the corresponding values ​​are 47.1 and 45.5 and on lime subsoil 31.9 and 2.4. The altitude distribution of the species ranges from sea level to over 400 meters.

    Way of life

    Territorial behavior

    Herd of black-faced impala in Etosha National Park
    Young male animal at a watering hole

    The black-nosed impala is both diurnal and nocturnal. Females and their offspring form herds that usually include 3 to 15 animals; the number rarely rises to over 20 individuals. However, at night, when the groups wander into more open areas, several herds can gather in resting places. In historical times, group concretions of 50 to 150 animals were observed, mostly near water. The herd size fluctuates over the year and is lowest in the short phase of the birth of the offspring, when pregnant females leave the main herd. The groups use action spaces which, according to studies in the Ongava Game Reserve on the southern edge of the Etosha National Park , can extend over up to 33.3 km² with a core area of ​​around 5.6 km². The size of these tail areas clearly exceeds that of the related black heel antelope . The action spaces include different types of landscape. In order to eat, the black-nosed impala often frequented transition areas from open clearings to more closed forest areas with high visibility and availability of fresh grass with low stalk heights of less than 1 m. She also prefers shady areas. Most of the time, the animals stand closer together within a radius of around 30 m. This use of space changes mainly during the birth of the offspring. The female animals with young then use areas for feeding that are more densely overgrown and less visible. In addition, areas with fresher grass are preferred, which may be related to the higher nutritional requirements of the nursing mothers. As a result, the usage areas of females with young animals do not overlap with those without offspring within an action area. However, the individual size of the tail area increases rapidly in the course of the birth of the offspring.

    Male animals show territorial behavior especially in the reproductive phase. They then establish territories that are within the action areas of the female herds. However, they do not seem to claim access to drinking water. Due to their dominant behavior, territorial males drive the young male offspring from the herd. Males often defecate in extensive latrine areas that are sometimes used by other species.

    nutrition

    The main diet of the black-nosed impala consists of both hard and soft vegetable food, which means that the animals can be regarded as specialized in mixed vegetable food. This means that grasses as well as leaves , seeds or fruits are part of the food repertoire. The black-nosed impala usually eats grass in the rainy season when the stalks are fresh. In the dry season, the species largely prefers soft vegetable food, which it then grazes in the river valleys. Frequently eradicated grasses can be found among the dog-tooth grasses , bluegrass and love grasses as well as in the genus Aristida . Herbs are represented by false asters and ragweeds , while the trees and shrubs include acacias as well as cassias , long threads or star bushes . The animals need water all year round.

    Reproduction

    Female with cub

    The reproductive phase of the black-nosed impala is limited to a short period between June and July. The birth of the offspring then also takes place in a tight time phase between December and January. It falls into the short rainy season. As a rule, a female gives birth to a single young, in exceptional cases there are twins . For birth, the female moves away from the herd and retreats into denser grass. It spends the following week alone with the newborn and only then rejoins the herd. At birth, the baby weighs around 5 kg. During the first nine months, it gains weight rapidly with an average monthly rate of 2.6 to 2.7 kg. Thereafter, the rate decreases continuously and is 1.0 to 1.3 kg for the next twelve months before it subsequently drops to less than 1 kg.

    Predators and parasites

    As a major predator is Leopard to look at. The cheetah also has a certain influence on the size and vitality of local populations . External parasites mostly include ticks of the genus Rhipicephalus . These often affect the outer ear canal, but are also found in the urogenital area. Internal parasites are flukes as Cooperioides or nematodes , such as Haemonchus . In general, due to the generally drier climate, the parasite infestation is not as intense as with the black heel antelope. Blood tests that were carried out on animals for resettlement in the Etosha National Park mostly showed no evidence of diseases such as foot-and-mouth disease , rinderpest or leptospirosis .

    Systematics

    Internal systematics of the Impalas according to Lorenzen et al. 2006
     Aepyceros  

     Aepyceros petersi


      Aepyceros melampus  

     A. melampus (Eastern Africa)


       

     A. melampus (southern Africa)




    Template: Klade / Maintenance / Style
    JV Barbosa du Bocage

    The Black-faced Impala is a kind from the genus of impala ( Aepyceros ) within the family of the Bovidae (Bovidae). The genus belongs to the subfamily of the Antilopinae and to its own tribe of the Aepycerotini , whose closest relatives are the goats ( Nesotragus ). The impalas today include two species that inhabit eastern and southern Africa. Special characteristics of the Impalas can be found in the lyre-like, strongly ribbed horns, which are only developed in male individuals, as well as in the lack of scent glands in the face, on the feet and in the groin area. Otherwise the animals largely resemble the other antelopes . Originally the genus was viewed as monotypical and several subspecies were identified. One included the black heel antelope ( A. m. Melampus ), which is widespread across eastern and southeastern Africa and includes several subpopulations . Separated from this, the black-nosed impala ( A. m. Petersi ) occurs endemically in the south-western part of the continent. Individual authors saw the black-nosed impala as an independent species, especially in the first and second third of the 20th century. Both forms can be easily distinguished on the basis of morphological and morphometric data, for example through the black facial stripes and the average larger body size of the black-nosed impala compared to the black-heeled antelope. Various molecular genetic studies from the beginning of the 2000s could then show that the two Impala populations differ significantly. In addition, in the Etosha National Park in Namibia , where the black-nosed impala has reached its natural limit of distribution, but the black-heeled antelope had been introduced by humans, no hybridization between the two groups could be detected. Colin P. Groves and Peter Grubb took this as an opportunity in 2011 to split the genus into two species in their revision of the ungulate systematics.

    The current population in the Etosha National Park goes back largely to 180 introduced individuals between 1968 and 1971, who were released in five different places with artificial water holes. The animals inhabit these areas to this day, but in the following three decades they spread to a total of around two dozen water points and covered a maximum of 31.5 km from their original place of release. The average distance covered between the water points during this time is 7.1 km. According to genetic data, the black-nosed impala in the Etosha National Park shows a high level of diversity, which means that five independent subpopulations can be distinguished, which in principle reflect the five groups released. Despite the genetic separation of the black-nosed impala and the black-heeled antelope, animals occasionally occur in northern South Africa that phenotypically correspond to the black-nosed impala, but DNA studies have shown that they belong to the black-heeled antelope. It is not yet clear whether there is a gene flow to the clearly separated population of the black-nosed impala in Namibia.

    The first scientific description of the black-nosed impala was written by José Vicente Barbosa du Bocage in 1879. It is based on a male and a female individual who had previously been collected by the Portuguese researcher José Alberto de Oliveira Anchieta near Moçâmedes and Humbe on the right bank of the Kunene in Angola and brought to Lisbon . The first locality is considered to be the type area of ​​the species. Bocage named the species after Wilhelm Peters , who confirmed his opinion that this was a form that was distinct from the black heel antelope.

    Hazard and protection

    The greatest threat to the black-nosed impala population is the spread of livestock farming and illegal hunting. Some of the animals killed are used as a food resource. The hunt in the Kaokoveld was immense, especially in the 1960s in the course of the armed conflict between the South West African People's Organization and the South African Army , so that a large part of the population was decimated. In addition, the species suffered from various periods of drought during this period. A further complicating factor was that the Kaokoveld lost its nature conservation status in 1970, which had existed since 1928. To save the species from extinction, around 180 individuals from the Kaokoveld were settled in the Etosha National Park in the transition from the 1960s to the 1970s , spread across five different regions. The population there has increased sharply since then, so that subsequently individual animals were again brought to private game farms. In total, around 3200 animals are native to the Etosha National Park and the adjacent game farms. In the Kunene area further to the north, another 1,000 individuals may possibly live. The IUCN currently does not differentiate between the Impalas at species level; they classify the entire population as “not endangered” ( least concern ). The nature conservation organization sees the black-nosed impala as a subspecies of the black heel antelope as "endangered" ( vulnerable ). The largest occurrence of the species is found today in the Etosha National Park. Among other things, preventing hybridization with the black heel antelope artificially settled in the region is an important protective measure. No information is available about the status of the black-nosed impala in the Iona National Park and in the Mupa National Park , both in Angola .

    literature

    • Hervé Fritz and Mathieu Bourgarel: Aepyceros melampus Impala. 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. 480-487
    • 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 World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 444-779 (pp. 623-624)
    • Eugene Jaubert: Observations on the habitat preferences and population dynamics of the Black-faced impala Aepyceros petersi Bocage, 1875 in South West Africa. Madoqua Ser. 1 3, 1971, pp. 55-65
    • JT du Toit: Ruminantia. In: JD Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Sub-region. Cambridge University Press, 2005, pp. 616-714 (pp. 707-708)

    Individual evidence

    1. ↑ a b c d e f J. T. du Toit: Ruminantia. In: JD Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Sub-region. Cambridge University Press, 2005, pp. 616-714 (pp. 707-708)
    2. ↑ a b c d e f g h 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 World. Volume 2: Hooved Mammals. Lynx Edicions, Barcelona 2011, ISBN 978-84-96553-77-4 , pp. 444-779 (pp. 623-624)
    3. ↑ a b c d e f Hervé Fritz and Mathieu Bourgarel: Aepyceros melampus Impala. 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. 480-487
    4. ↑ a b Henriette Oboussier: To the knowledge of the black heel antelope (Impala) Aepyceros melampus with special consideration of the cerebral furrow pattern and the pituitary gland. Results of the research trips to South Angola and East Africa. Journal for Morphology and Ecology of Animals 54, 1965, pp. 531-550
    5. ↑ a b c d e f g h Eugene Jaubert: Observations on the habitat preferences and population dynamics of the Black-faced impala Aepyceros petersi Bocage, 1875 in South West Africa. Madoqua Ser. 1 3, 1971, pp. 55-65
    6. ↑ a b c Tammie K. Matson, Anne W. Goldizen and Peter J. Jarman: Microhabitat use by black-faced impala in the Etosha National Park, Namibia. Journal of Wildlife Management 69 (4), 2004, pp. 1708-1715
    7. ↑ a b c d Tammie K. Matson, Anne W. Goldizen, Peter J. Jarman and Anthony R. Pople: Dispersal and seasonal distribution of black-faced impala in the Etosha National Park, Namibia. African Journal of Ecology 44, 2006, pp. 247-255
    8. ↑ a b c Tammie K. Matson, DA Putland, Peter J. Jarman, J. Le Roux and AW Goldizen: Influences of parturition on home range and microhabitat use of female black ‐ faced impalas. Journal of Zoology 271 (3), 2007, pp. 318-327, doi: 10.1111 / j.1469-7998.2006.00216.x
    9. ↑ Tammie K. Matson, Anne W. Goldizen and Peter J. Jarman: Factors affecting the success of translocations of the black-faced impala in Namibia. Biological Conservation 116, 2004, pp. 359-365
    10. ↑ William B. Karesh, Aron Rothstein, Wendy Green, HO Reuter, W. Emmett Braselton, Alfonso Torres and Robert A. Cook: Health evaluation of black-faced impala (Aepyceros melampus petersi) using blood chemistry and serology. Journal of Zoo and Wildlife Medicine 28 (4), 1996, pp. 361-367
    11. ↑ a b Eline D. Lorenzen, Peter Arctander and Hans R. Siegismund: Regional Genetic Structuring and Evolutionary History of the Impala Aepyceros melampus. Journal of Heredity 97 (2), 2006, pp. 119-132, doi: doi: 10.1093 / jhered / esj012
    12. ↑ MV Kuznetsova and MV Kholodova: Revision of Phylogenetic Relationships in the Antilopinae Subfamily on the Basis of the Mitochondrial rRNA and β-Spectrin Nuclear Gene Sequences. Doklady Biological Sciences 391 (1-6), 2003, pp. 333-336
    13. ^ Eva V. Bärmann and Tim Schikora: The polyphyly of Neotragus - Results from genetic and morphometric analyzes. Mammalian Biology 79, 2014, pp. 283-286
    14. ↑ Juan P. Zurano, Felipe M. Magalhães, Ana E. Asato, Gabriel Silva, Claudio J. Bidau, Daniel O. Mesquita and Gabriel C. Costa: Cetartiodactyla: Updating a time-calibrated molecular phylogeny. Molecular Phylogenetics and Evolution 133, 2019, pp. 256-262
    15. ↑ Jonathan Kingdon: Tribe Aepycerotini Impala. 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. 477-479
    16. ↑ Don E. Wilson and DeeAnn M. Reeder: Mammal Species of the World . Johns Hopkins University Press, Baltimore, 2005 ISBN 0-8018-8221-4 ( [1] )
    17. ↑ C. Bastos-Silveira and AM Lister: A morphometric assessment of geographical variation and subspecies in impala. Journal of Zoology 271 (3), 2007, pp. 288-301
    18. ↑ Louise Gray Listeners Ting and Peter Arctander: Phylogeography and conservation of impala and kudu greater. Molecular Ecology 10, 2001, pp. 711-719
    19. ↑ a b Eline D. Lorenzen and Hans R. Siegismund: No suggestion of hybridization between the vulnerable black ‐ faced impala (Aepyceros melampus petersi) and the common impala (A. m. Melampus) in Etosha National Park, Namibia. Molecular Evolution 13 (10), 2004, pp. 3007-3019
    20. ↑ Colin P. Groves and Peter Grubb: Ungulate Taxonomy. Johns Hopkins University Press, 2011, pp. 1-317 (pp. 108-280)
    21. ^ J. Paul Grobler, Kyla N. Hayter, Christiaan Labuschagne, EJ Nel and Willem G. Coetzer: The genetic status of naturally occurring black-nosed impala from northern South Africa. Mammalian Biology 82, 2017, pp. 27-33
    22. ↑ José Vicente Barbosa du Bocage: List of the Antilopes d'Angola. Proceedings of the Zoological Society 1878, pp. 741-745 ( [2] )
    23. ↑ a b Wendy CH Green and Aron Rothstein: Translocation, Hybridization, and the Endangered Black ‐ Faced Impala. Conservation Biology 12 (2), 1998, pp. 475-480, doi: 10.1111 / j.1523-1739.1998.96424.x
    24. ^ IUCN SSC Antelope Specialist Group: Aepyceros melampus. The IUCN Red List of Threatened Species 2016. e.T550A50180828 ( [3] ), last accessed September 28, 2019
    25. ^ IUCN SSC Antelope Specialist Group: Aepyceros melampus ssp. petersi. The IUCN Red List of Threatened Species 2016. e.T550A50180804 ( [4] ), last accessed on September 28, 2019
    26. ↑ Tammie K Matson: Future management of the Black-faced Impala in Namibia: A co-operative, multi-pronged approach to the conservation of a vulnerable subspecies. Ecological Journal 7, 2006, pp. 96-365

    Web links

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