Dark-footed elephant shrew
| Dark-footed elephant shrew | ||||||||||||
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| Elephantulus fuscipes | ||||||||||||
| ( Thomas , 1894) |
The dark- footed elephant shrew ( Elephantulus fuscipes ), also dark- footed elephant shrew or black-footed elephant shrew , is a species from the genus of elephant shrews . Its range is in eastern and central Africa , but it is not very extensive. The habitat consists of open forest savannas. The species is similar to other members of the genus and is characterized by a trunk-like elongated nose and only short front legs compared to the long hind legs. There is hardly any evidence about the way of life of the dark-footed elephant shrew. It was scientifically introduced in 1894, but for some time it was considered identical to the short-nosed elephant shrew . Data on the population and its possible endangerment have not yet been collected.
description
Habitus
The dark-footed elephant shrew is a medium-sized representative of the elephant shrew and externally resembles the dark elephant shrew ( Elephantulus fuscus ), but is slightly larger than it. It has a head-body length of 12.6 to 14.8 cm and a tail length of 8.6 to 10 cm. Investigated individuals from Uganda had a head-trunk length of 11 to 12 cm and a tail 8 to 9 cm long. Thus the tail with only 65 to 75% of the length of the rest of the body is the comparatively shortest within the genus. The weight varies from 52 to 77 g. In outward appearance, the dark-footed elephant shrew corresponds to the other elephant shrews. It is characterized by a large head with a trunk-like elongated nose and, compared to the long hind legs, very short front legs. The fur on the back is soft, the individual hairs are dark gray to black, only the tips are brown in color. As a result, the back side appears dark brown, but numerous longer and black-tipped hair give it a saturated dark shade. The fur on the sides of the body is lighter, the peritoneum is gray-white. The tail is also two-colored and dark on top, a little lighter on the underside. There is no tuft of elongated hair at the tip of the tail, as is found in some South African species. The ears are moderately long with 20 to 22 mm, their tips are rounded. The supratragus is turned backwards and clearly inflated, noticeably stronger than that of the dark elephant shrew and the short-nosed elephant shrew ( Elephantulus brachyrhynchus ); the characteristic serves to differentiate the three types. Unlike the short-nosed elephant shrew, there is no dark spot of color behind the ears. The eyes are large and surrounded by an indistinct, lighter to whitish eye ring, which is sometimes only spotted. Lips and chin are lighter in color. The front and rear feet each consist of five rays that have claws. The hind foot is less stretched than in other elephant shrews and becomes 25 to 28 mm long.
Skull and dentition features
The skull becomes 35.6 to 36.6 mm long and 16.9 to 17.9 mm wide at the zygomatic arches . Overall, it appears very narrow. The teeth comprises 42 teeth and shows the following dental formula : . The formation of a third, albeit small, molar in the lower jaw is unusual for today's elephant shrews and so only occurs in the dark and short-nosed elephant shrews. In the front dentition, the three incisors are approximately the same size. The canine resembles the posterior molar teeth ( molar-shaped ). It is separated from the incisors by a longer diastema than the dark elephant shrew , which exceeds the base length of the canine. The entire upper row of teeth has a length of 17.8 to 18.9 mm.
distribution
The distribution area of the dark-footed elephant shrew only covers a small area in eastern and central Africa . It extends from the southwest of Sudan ( South Sudan ) over the northeast of the Democratic Republic of the Congo to the north of Uganda , a somewhat remote evidence is further south on Mount Elgon . An assumed occurrence in the far east of the Central African Republic has not yet been confirmed. The species is bound by its range to the northern and western rainforest - savannah - mosaic landscapes. The preferred habitat is predominantly open forest savannahs. The dark-footed elephant shrew is rather rare, but there are reports of a regionally more frequent occurrence in the Democratic Republic of the Congo. There is only marginal overlap with the distribution areas of the short-nosed and red-brown elephant shrew ( Elephantulus rufescens ).
Way of life
The way of life of the dark-footed elephant shrew is largely unexplored, only one female from the Democratic Republic of the Congo is known to have carried an embryo .
Systematics
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Internal systematics of elephants according to Heritage et al. 2020
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The dark-footed elephant shrew is an independent species from the genus of elephant shrews ( Elephantulus ), which comprises a total of nine species. The elephant shrews are distributed over large parts of southern and eastern Africa . They belong to the family of elephants (Macroscelididae) within the order of the same name (Macroscelidea). Family and order are represented by predominantly smaller animals that are endemic to Africa. They can be divided into two subfamilies. One of the two subfamilies are the Rhynchocyoninae, which with the proboscis dog ( Rhynchocyon ) consist of only one genus and are therefore monotypical . They include the largest representatives, which are predominantly adapted to densely forested habitats . The second subfamily is formed by the Macroscelidinae. Besides the elephant shrews, it also includes the proboscis ( Petrodromus ), the North African elephant shrew ( Petrosaltator ), the Somali elephant shrew ( Galegeeska ) and the species of the genus Macroscelides . The representatives of this group mostly inhabit drier and more open landscapes and can therefore be found in savannahs as well as in desert-like regions. With the help of molecular genetic investigations, a separation of the two subfamilies in the Lower Oligocene could be determined about 32.8 million years ago. The Macroscelidinae began to diversify more strongly in the Upper Oligocene around 28.5 million years ago.
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Internal system of elephant shrews according to Smit et al. 2011
The representation here neglects the positions of Petrodromus , Petrosaltator , Galegeeska and Macroscelides , all four of which are currently deeply embedded in Elephantulus , making the genus of elephant shrews paraphyletic . |
In addition, the molecular genetic investigations showed that the elephant shrews currently represent a paraphyletic group. This is shown by the deep embedding of Petrosaltator , Petrodromus and Macroscelides in the genus Elephantulus . However, the analyzes support the close relationship of a group predominantly distributed in the southern and eastern species. The exact position of the dark-footed elephant shrew within the genus could not be determined, however, together with the dark-footed elephant shrew ( Elephantulus fuscus ) it forms an allopatric group. Due to the development of a third lower molar, a close relationship between the two species and the short-nosed elephant shrew ( Elephantulus brachyrhynchus ) was originally assumed, which the genetic studies could not confirm. At times, the dark-footed and the dark elephant shrew were considered to be of the same species as the short-nosed elephant shrew due to the third rear molar in the lower jaw. The characteristic also served to separate the genus Nasilio from Elephantulus in 1906 (both genera also differed from Macroscelides due to their less swollen tympanic membranes ). The type species of Nasilio represented the short-nosed elephant shrew. A revision of the elephant shrew in 1968, however, reunited Nasilio with Elephantulus , moreover it recognized the dark-footed elephant shrew as an independent species. Subspecies are not known, nor are there any fossil records.
The first scientific description of the dark-footed elephant shrew was carried out by Oldfield Thomas in 1894. He used the name Macroscelides fuscipes . The specimen that was available to him for the description was a not fully grown female with a body length of 10.2 cm and a tail length of 7.6 cm, which still had the milk teeth. However, due to the different color of the fur, the short tail and the short hind feet, Thomas found it justified to set up the new species. As a type locality he gave N'doruma in the area of the local ethnic group of the Azande in what is now the Democratic Republic of the Congo.
Threat and protection
It is possible that the population of the dark-footed elephant shrew is not endangered, as the preferred habitat is little influenced and used by humans. Due to the limited distribution area and the very little information about the species, the IUCN classifies them as “insufficient data basis” ( data deficient ). The dark-footed elephant shrew is present in some protected areas.
literature
- GB Corbet and J. Hanks: A revision of the elephant-shrews, Family Macroscelididae. Bulletin of the British Museum (Natural History) Zoology 16, 1968, pp. 47-111
- Stephen Heritage: Macroscelididae (Sengis). 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. 206-234 (pp. 231-232), ISBN 978-84-16728-08-4
- Mike Perrin: Elephantulus fuscipes Dusky-footed Sengi (Dusky-footed Elephant-shrew). 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. 266-267
Individual evidence
- ↑ a b c d e Mike Perrin: Elephantulus fuscipes Dusky-footed Sengi (Dusky-footed Elephant-shrew). 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. 266-267
- ^ A b Erik Thorn and Julian Kerbis Peterhans (with the participation of Jonathan Baranga, Michael Huhndorf, Rainer Hutterer and Robert Kityo): Small mammals of Uganda. Bats, shrews, hedgehog, golden-moles, otter-tenrec, elephant-shrews, and hares. Bonn Zoological Monographs 55, 2009, pp. 1–164 (pp. 102–106)
- ↑ a b c d Stephen Heritage: Macroscelididae (Sengis). 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. 206-234 (pp. 231-232), ISBN 978-84-16728-08-4
- ↑ a b c G. B. Corbet and J. Hanks: A revision of the elephant-shrews, Family Macroscelididae. Bulletin of the British Museum (Natural History) Zoology 16, 1968, pp. 47-111
- ↑ M. Séguignes: Contribution à l'étude de la reproduction d'Elephantulus rozeti (Insectivora, Macroscelididae). Mammalia 53 (3), 1989, pp. 377-386
- ↑ a b Steven Heritage, Houssein Rayaleh, Djama G. Awaleh and Galen B. Rathbun: New records of a lost species and a geographic range expansion for sengis in the Horn of Africa. PeerJ 8, 2020, p. E9652, doi: 10.7717 / peerj.9652
- ↑ a b Hanneline Adri Smit, Bettine Jansen van Vuuren, PCM O'Brien, M. Ferguson-Smith, F. Yang and TJ Robinson: Phylogenetic relationships of elephant-shrews (Afrotheria, Macroscelididae). Journal of Zoology 284, 2011, pp. 133-143
- ^ Mike Perrin and Galen B. Rathbun: Order Macroscelidea - Sengis (Elephant-shrews). 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. 258-260
- ↑ Oldfield Thomas and Harold Schwann: The Rudd exploration of South Africa. V. List of mammals obtained by Mr. Grant in the North East Transvaal. Proceedings of the Zoological Society of London 1906, pp. 575-591 ( online )
- ↑ Oldfield Thomas: Description of two new species of Macroscelides. The Annals and Magazine of Natural History 6 (13), 1894, pp. 67-70 ( online )
- ↑ Galen B. Rathbun: Elephantulus fuscipes. The IUCN Red List of Threatened Species 2015. e.T42659A21288575 ( online ); last accessed on April 13, 2015
Web links
- Elephantulus fuscipes inthe IUCN Red List of Threatened Species 2014.3. Posted by: Rathbun, 2008. Retrieved April 8, 2015.