Western cliff elephant shrew

Western cliff elephant shrew
Western cliff elephant shrew ( Elephantulus rupestris )
Systematics
Superordinate : Afrotheria without rank: Afroinsectiphilia Order : Elephant jerk (Macroscelidea) Family : Elephant jerk (Macroscelididae) Genre : Elephant shrews ( Elephantulus ) Type : Western cliff elephant shrew
Scientific name
Elephantulus rupestris
( A. Smith , 1831)

The western cliff elephant shrew ( Elephantulus rupestris ), sometimes also rock elephant shrew or western elephant shrew , is a species from the genus of elephant shrews . It occurs in south-western Africa, where it inhabits dry and rocky landscapes. Outwardly, like the other representatives of the elephant shrews, it is characterized by the trunk-like elongated nose and the short front and long rear legs. It is a ground dweller whose main activities take place during the day or during the twilight period. The food consists mainly of insects , otherwise there are only a few studies on the way of life of the species. The western cliff elephant shrew was scientifically introduced in 1831. Especially in the 1950s and later there was uncertainty about the exact systematic position of the species and the Use of the scientific name resulting from the loss of the material originally used for the first description .

description

Habitus

Western cliff elephant shrew

With a total length of 23.9 to 29.7 cm, the western cliff elephant shrew is one of the larger representatives of the elephant shrews. The tail reaches about 115% of the head-trunk length and measures between 12.2 and 16.6 cm. The total weight varies from 54 to 77 g. Investigations on 24 individuals from Namibia showed that there is a slight sexual dimorphism and that males are usually slightly larger than females. According to the study, male animals had an average total length of 26.9 cm, females of 26.3 cm. The tail measured 14.6 and 14.2 cm respectively. The males also exceeded the females in numerous other body sizes. In the same way, studies in the Gamkaberg nature reserve showed an average of 57.6 g for females, a lower weight than for males, who weighed around 63 g. Like all elephant shrews, the western cliff elephant shrew is characterized by a large head with a trunk-like elongated nose and very long hind legs compared to the front legs. The fur is very soft, especially on the back, the individual hairs there are dark gray with reddish brown tips. As a result, the back fur appears characteristically gray-brown to reddish-brown in color. Longer hairs also appear along the center line of the back, the tips of which are darker to black in color. The color of the fur on the sides of the body is becoming increasingly gray, on the stomach and limbs it is almost white. Here the individual hairs also show white tips. The head and cheeks are characterized by a gray color, sometimes with a hint of yellow. There is sometimes a darker center line running on top of the nose. The ears are relatively large with a length of 22 to 38 mm and have more pronounced tips than, for example, the Cape elephant shrew ( Elephantulus edwardii ), the tragus is well developed. A reddish-brown spot appears prominently behind the ears, some of which extends up to the neck. It is much more noticeable than that of the Cape elephant shrew or the Karoo cliff elephant shrew ( Elephantulus pilicaudus ). The large eyes are framed by a light, whitish eye ring, which is interrupted above and below. The long tail is black on top, lighter on the underside, and becomes completely black towards the end. The tip of the tail is marked by a thick bush of hair that is more prominent than in the species of elephant shrew mentioned or in the dryland elephant shrew ( Elephantulus intufi ). The individual hairs reach here up to 6 mm in length. Front and rear legs each end in five-pointed hands and feet with short claws. The soles of the feet are colored black, the entire rear foot measures between 34 and 39 mm in length.

Skull and dentition features

The length of the skull is between 35 and 38.6 mm, the largest width between the zygomatic arches varies from 19.2 to 20.9 mm. The nasal bone becomes around 14 mm long, the bone seam between this and the median jawbone is sinusoidal . The tympanic bladder is only slightly swollen. In the dentition of adult animals teeth 40 are typically formed, the dental formula is: . The middle incisor (I2) of the upper row of teeth is significantly smaller than the other two. The canine shows a rather molarenartige shape ( Molariform ), at the upper first premolar just a tongue-sided protuberances occurs. The second premolar is also molar-shaped , which connects the western cliff elephant shrew with the dryland elephant shrew. In contrast to this, on the second and third lower premolars there are three, instead of just two, rear cusps, which stand in a triangle behind the main cusp. The length of the upper row of teeth from the first incisor to the last molar averages 19.1 mm. ${\displaystyle {\frac {3.1.4.2}{3.1.4.2}}}$

distribution

Distribution area (green) of the western cliff elephant shrew

The western cliff elephant shrew is endemic to southwestern Africa. It occurs in South Africa from the coastal region of the Eastern Cape Province , roughly at the height of East London , in a more or less narrow strip to Namaqualand in the western part of the Northern Cape Province . It has not been proven in the Western Cape Province . In Namibia , the distribution area continues in the western part of the country to the north to the Kaokoveld near the border with Angola . The size of the entire distribution area is around 450,000 km². It mainly includes dry to very dry and open landscapes such as the Karoo , parts of the Namib , but also the more overgrown fynbos . The species is bound to habitats with rocky subsoil and occurs in Kopjes areas , less often on scree fields. Part of the distribution area overlaps with that of the dryland elephant shrew ( Elephantulus intufi ), which, however, prefers significantly more sandy soils. However, this seems to be much more common in the Kaokoveld than the western cliff elephant shrew, the number of which only increases towards the south. More precise statements on the population density are hardly available; on the Tumasberg in Namibia it was determined to be 0.4 individuals per hectare. It is possible that the northern groups are more isolated from the southern ones. The two species can sometimes be confused, particularly in areas where they occur together. In the south, there are also overlaps with the Cape elephant shrew ( Elephantulus edwardii ) and the Karoo cliff elephant shrew ( Elephantulus pilicaudus ). However, it is unclear whether the individual species also use the same habitats.

Way of life

Territorial behavior

Historical representation of the western cliff elephant shrew from 1839

The way of life of the western cliff elephant shrew is insufficiently researched. The main activities take place during the day or at dusk. The species lives on the ground and is well adapted to rocky and stony terrain. As a fast ( cursorial ) runner, she moves four-footed continuously; in the event of danger she can jump over to quick jumps. It can achieve average speeds of 23.6 km / h, the highest measured speed was 28.8 km / h. The animals have action spaces in which they prefer to stay. The size of the individual roaming areas is unknown. Investigations on Tumasberg, a Kopje in the gravel plains of today's Namib Skeleton Coast National Park in Namibia showed that individual individuals at least moved over a distance of more than 240 m, which suggests relatively large areas, possibly larger than 1.2 ha. A positive relationship with figwort plants and sweet grasses was also found in the region. The western cliff elephant shrew mostly seeks crevices in the rock for protection. The animals switch between their preferred resting and resting places via clearly defined paths and paths. Probably the western rock elephant shrew forms monogamous pair bonds, as for other elephant shrews is detected. Indications of this result from the fact that, as a rule, male and female animals could be observed together in one region.

Various sounds such as meowing or clicking are used to communicate with conspecifics, as well as scent marks made from glandular secretions . Typical is a drumming with the hind legs on the ground. In the case of the western cliff elephant shrew, this consists of regular strokes. A series comprises 30 to 50 drum beats at short intervals of 15 to 25 ms. The length of a drum series is 1 to 1.5 s.

nutrition

In general, the western cliff elephant shrew is an outspoken insect eater, whose main diet includes ants and termites . The body temperature averages 36.9 ° C, but fluctuates over the course of the day and the seasons. Due to the very dry climate in the distribution area, the nights can be very cool, as well as the temperatures drop sharply in winter. As with other representatives of the elephant shrews, the onset of a torpor in the western cliff elephant shrew has been proven during adverse environmental conditions. It occurs frequently in winter, but is also occupied for summer. In winter, however, longer and deeper cold rigors can be achieved, which last from around five hours to over eight hours and more, while in summer they last an hour on average. The body temperature also drops much more sharply in winter, the lowest body temperature measured was 8.9 ° C. Torpor occurs mainly during the night and begins in winter and after midnight in summer. In addition, it is more frequently used in females than in males.

Reproduction

Reproduction may take place year-round, fertilized females have been observed throughout the year and a young in the Namib in April. The non-seasonal reproduction is possibly due to the specialization in insects and the resulting good, year-round food supply, with the fluid requirement being covered by the food. A litter includes two young animals, which, like the other species of elephant shrews, are very well developed. Females are likely to give birth several times a year. Life expectancy in the wild is unknown. In human care, animals reached a maximum age of four years and two months.

Predators and parasites

The barn owl appears as an important predator . External parasites have been detected with fleas such as Ctenocephalides , Demeillonia or Xenopsylla and ticks such as Ixodes , Haemaphysalis and Rhipicephalus , as well as mites.

Systematics

Internal systematics of elephants according to Heritage et al. 2020  Macroscelididae     Macroscelidinae     Macroscelidini    Galegeeska      Petrodromus      Petrosaltator      Macroscelides   Elephantulini    Elephantulus   Rhynchocyoninae    Rhynchocyon

The western cliff elephant shrew belongs as an independent species to the genus of elephant shrews ( Elephantulus ), to which eight other species are assigned. The elephantulus are over large parts of southern and eastern Africa used and form part of the family of shrews (Macroscelididae) within the same order (Macroscelidea), the African endemic occurs. The order includes rather small representatives and today contains two subfamilies with the Rhynchocyoninae and the Macroscelidinae . To the Rhynchocyoninae only the proboscis dogs ( Rhynchocyon ) are counted, the subfamily is thus monotypical . They represent the largest members of the elephant and inhabit densely forested habitats . In addition to the elephant shrews , the trunk rat ( Petrodromus ), the North African elephant shrew ( Petrosaltator ), the Somali elephant shrew ( Galegeeska ) and the species of the genus Macroscelides are referred to the Macroscelidinae . These are mostly residents of drier and more open landscapes, which means they occur in savannahs as well as in desert-like regions. Molecular genetic studies revealed a separation of the two subfamilies as early as the Lower Oligocene about 32.8 million years ago. At the beginning of the Upper Oligocene, around 28.5 million years ago, the Macroscelidinae saw the first major fragmentation.

Internal system of elephant shrews according to Smit et al. 2011  Elephantulus    Elephantulus fuscus      Elephantulus fuscipes      Elephantulus rufescens      Elephantulus brachyrhynchus      Elephantulus rupestris      Elephantulus intufi      Elephantulus myurus      Elephantulus edwardii      Elephantulus pilicaudus 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 .

Sir Andrew Smith

Apart from the general relationship of the elephant shrews, the molecular genetic analyzes also showed that the elephant shrews currently form a paraphyletic group. This is indicated by the deep embedding of Petrosaltator , Petrodromus and Macroscelides in the genus Elephantulus . However, the genetic investigations also revealed the close relationship of a group of species common to South and East Africa. This makes the dryland elephant shrew ( Elephantulus intufi ) the closest related species to the western cliff elephant shrew. As a sister group , a lift clade out that from the red-brown elephant shrew ( Elephantulus rufescens ) and the short-snouted elephant shrew ( Elephantulus brachyrhynchus there). In a closer relationship to this common family group there is also a clade of other, predominantly South African species, consisting of the eastern cliff elephant shrew ( Elephantulus myurus ), the Cape elephant shrew ( Elephantulus edwardii ) and the Karoo cliff elephant shrew, which was only newly described in 2008 ( Elephantulus pilicaudus ) composed. It can be assumed that the ancestors of this large community of species originally lived in eastern Africa. During a phase of increasing aridization of the continent at the beginning of the Upper Miocene around 11.5 million years ago, some of these early representatives of the elephant shrews migrated south and south-west and thus to the present-day distribution areas. The elephant shrews were further split up in the course of a renewed desiccation of the landscapes of southern Africa in the transition from the Upper Miocene to the Pliocene around 6 million years ago.

Numerous subspecies were described during the 1930s and 1940s, including E. r. gordoniensis , E. r. kobosensis , E. r. montanus or E. r. tarri . The distinctions were mostly based only on slightly different coat colors, so some specimens from the western and northwestern distribution area should be paler. But this could not be confirmed. The following anatomical and morphological investigations also did not reveal any serious deviations within the species, which is also supported by genetic studies. However, the genetic studies showed that the species consists of individual isolated groups, which is due to the irregular distribution of rocky habitats over the range. As a rule, no subspecies are identified today.

Fossil finds have so far only been reported from Hoedjiespunt and from the Elands Bay Cave near Elands Bay in the South African province of Western Cape on the west coast of South Africa. The first site dates to the Middle Pleistocene around 300,000 to 200,000 years ago, the latter, with an age of 13,600 to 13,300 years, belongs to the late Young Pleistocene . The two occurrences are over 200 km south of the current range of the western cliff elephant shrew, which suggests a shrinking of the habitats or a migration of the species to the north in the past.

The first scientific description of the western cliff elephant shrew was in 1831 by Andrew Smith in a letter to the Zoological Society of London . In this, Smith announced that he had discovered the species he called Macroscelides rupestris in the mountains near the mouth of the Oranje in a predominantly rocky area, which is considered a type area (today's Namaqualand ). As a special feature compared to the then known short-eared elephant ( Macroscelides proboscideus) , Smith emphasized on the one hand the color of the fur and on the other hand the conspicuous yellowish-brown spots behind the ears. Smith handed over the type material of the species published by him in 1831 and 1939 and other specimens to the Natural History Museum in London . However, it was obviously lost there, since none of the animals with the identification E. rupestris that were collected by Smith turned out to be the western cliff elephant shrew, but largely corresponded to the eastern cliff elephant shrew, which is not common on the Orange River. This also led to confusion in the scientific naming. In the 1950s, for example, the western cliff elephant shrew, including its subspecies used at that time, was included within the largely sympatric dryland elephant shrew. Due to the lack of a holotype and the existing finds, the eastern cliff elephant shrew and, in some cases, also the Cape elephant shrew , were given the scientific name Elephantulus rupestris . This confusion only resolved in 1968, when a revision of the elephant family by Gordon Barclay Corbet and John Hanks established a neotype for Elephantulus rupestris , the location of which coincides with that given by Andrew Smith. As a result, the western cliff elephant shrew has been listed as an independent species again since the mid-1970s.

Threat and protection

There are currently no known major threats to the population of the western cliff elephant shrew. The distribution in mainly semi-desert arid landscapes hardly leads to conflicts with humans. Only in river valleys can there be overlaps with human activities through the expansion of settlements or the expansion of arable and pasture areas, for example in the area of ​​the Orange River . As a result, among other things, excessive sheep and goat breeding could lead to greater desertification , but this has so far only happened to a limited extent. However, it cannot be ruled out that this will result in a greater loss of habitat for the western cliff elephant shrew in the future, which is why closer monitoring of these developments is called for. The IUCN currently lists the western cliff elephant shrew as "not endangered" ( least concern ). The species is present in several protected areas.

So far it has rarely been shown in zoological institutions, the only holder of European zoo history was, at the beginning of the last century, London.

literature

• 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 (p. 233) ISBN 978-84-16728-08-4
• Mike Perrin: Elephantulus rupestris Western Rock Sengi (Western Rock 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. 275-276
• Galen B. Rathbun: Elephantulus rupestris (A. Smith, 1831) - Western rock elephant-shrew. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 29-30

Individual evidence

1. ↑ ^{a b} J. O. Matson and BR Blood: Morphological variability and species limits in elephant shrews (Elephantulus intufi and E. rupestris) from Namibia. Mammalia 62 (1), 1997, pp. 77-93
2. ↑ ^{a b} Rebecca Oelkrug, Carola W. Meyer, Gerhard Heldmaier and Nomakwezi Mzilikazi: Seasonal changes in thermogenesis of a free-ranging afrotherian small mammal, the Western rock elephant shrew (Elephantulus rupestris). Journal of Comparative Physiology B 182, 2012, pp. 715-727
3. ↑ ^{a b c d e f g h} Galen B. Rathbun: Elephantulus rupestris (A. Smith, 1831) - Western rock elephant-shrew. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 29-30
4. ↑ ^{a b c d e f g h i} Mike Perrin: Elephantulus rupestris Western Rock Sengi (Western Rock 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. 275-276
5. ↑ ^{a b c} Hanneline Adri Smit, Terence J. Robinson, Johan Watson and Bettine Jansen van Vuuren: A New Species of Elephant-shrew (Afrotheria: Macroscelidea: Elephantulus) from South Africa. Journal of Mammalogy 89 (5), 2008, pp. 1257-1268
6. ↑ ^{a b c d e f} 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 (p. 233) ISBN 978-84-16728-08-4
7. ↑ ^{a b c d} 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
8. ↑ ^{a b} Mike Perrin, C. FitzGibbon, C. Stuart, M. Griffin (IUCN SSC Afrotheria Specialist Group) and H. Smit (Stellenbosch University): Elephantulus rupestris. The IUCN Red List of Threatened Species. Version 2014.3. ( [1] ); last accessed on March 5, 2015
9. ↑ ^{a b c} P. C. Withers: Ecology of a small mammal community on a rocky outcrop in the Namib Desert. Madoqua 11 (3), 1979, pp. 229-246
10. ^ Deanna K. Tolliver, Lynn W. Robbins, IL Rautenbach, Duane A. Schlitter and CG Coetzee: Biochemical Systematics of Elephant Shrews from Southern Africa. Biochemical Systematics and Ecology 17 (4), 1989, pp. 345-355
11. ↑ Barry G. Lovegrove and Metobor O. Mowoe: The evolution of micro-cursoriality in mammals. The Journal of Experimental Biology 217, 2014, pp. 1316-1325
12. ↑ AS Faurie, ER and MR Dempster Perrin: Footdrumming patterns of southern African elephant-shrews. Mammalia 60 (4), 1996, pp. 567-576
13. ^ Justin G. Boyles, Ben Smit, Catherine L. Sole and Andrew E. McKechnie: Body temperature patterns in two syntopic elephant shrew species during winter. Comparative Biochemistry and Physiology, Part A 161, 2012, pp. 89-94
14. ^ Philip C. Withers: Seasonal reproduction by small mammals of the Namib desert. Mammalia 47 (2), 1983, pp. 195-204
15. ^ Gea Olbricht: Longevity and fecundity in sengis (Macroscelidea). Afrotherian Conservation 5, 2007, pp. 3-5
16. ↑ LJ Fourie, JS du Toit, DJ Kok and IG Horak: Arthropod parasites of elephant-shrews, with particular reference of ticks. Mammal Review 25, 1995, pp. 31-37
17. ↑ ^{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
18. ↑ ^{a b c} 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
19. ^ 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
20. ↑ Hanneline A. Smit, Johan Watson and Bettine Jansen van Vuuren: Relative importance of habitat connectivity in shaping the genetic profiles of two southern African elephant-shrews. Journal of Biogeography 37, 2010, pp. 857-864
21. ↑ Thalassa Matthews, Christiane Denysund John E. Parkington: The Palaeoecology of the micromammals from the late middle Pleistocene site of Hoedjiespunt 1 (Cape Province, South Africa). Journal of Human Evolution 49, 2005, pp. 432-451
22. ^ Thalassa Matthews, Christiane Denys and John E. Parkington: Community evolution of Neogene micromammals from Langebaanweg 'E' Quarry and other west coast fossil sites, south-western Cape, South Africa. Palaeogeography, Palaeoclimatology, Palaeoecology 245, 2007, pp. 332-352
23. ↑ Patricia A. Holroyd: Past records of Elephantulus and Macroscelides: geographic and taxonomic issues. Afrotherian Conservation 7, 2009, pp. 3-7
24. ^ Andrew Smith: Letter accompanying a collection of fishes from South Africa. Proceedings of the Zoological Society of London 1830/1831, p. 11 ( [2] )
25. ^ Andrew Smith: Illustrations of the Zoology of South Africa. Mammalia. London, 1839 (plates 11 and 15) ( [3] )
26. ↑ Zoo animal list ( [4] ), last accessed on June 15, 2015

Web links

Commons : Western cliff elephant shrew ( Elephantulus rupestris )  - Collection of images, videos and audio files

• Elephantulus rupestris inthe IUCN Red List of Threatened Species 2014.3. Posted by: Perrin, FitzGibbon, Stuart, Griffin & Smit, 2008. Retrieved March 3, 2015.