Cape elephant shrew

Cape elephant shrew
Cape elephant shrew ( Elephantulus edwardii ) (drawing from the first description by Andrew Smith, 1839)
Systematics
Superordinate : Afrotheria without rank: Afroinsectiphilia Order : Elephant jerk (Macroscelidea) Family : Elephant jerk (Macroscelididae) Genre : Elephant shrews ( Elephantulus ) Type : Cape elephant shrew
Scientific name
Elephantulus edwardii
( A. Smith , 1839)

The Cape elephant shrew ( Elephantulus edwardii ) is a species in the genus of elephantulus within the family of shrews . It is endemic in the southern and western parts of South Africa, where it predominantly inhabits the arid landscapes of the Karoo , but also of the more overgrown fynbos . Like all elephant shrews, the small mammal is characterized by its trunk-like elongated nose and short front and long hind legs. As a specialized and nimble ground dweller, the species is adapted to stony and rocky subsoil. The animals live singly or in monogamous pairs, a litter consists of two young on average. The main food consists of insects and parts of plants, making the Cape elephant shrew an omnivore. In their search for food, however, it also acts as a pollinator for some plants. The species was first described in 1839. In some cases it was synonymous with the eastern cliff elephant shrew . In general, the Cape elephant shrew is not very common, but its population is not considered threatened.

description

Habitus

The Cape elephant shrew is one of the medium-sized representatives of the elephant shrews and has a total length of 22.0 to 28.8 cm. Of this, between 11.5 and 14.9 cm is accounted for by the tail, which is the same length or slightly longer than the rest of the body. The weight varies from 36 to 65 g. At an average of 47 g, males are slightly lighter than females, which can weigh around 55 g on average. Investigations of at least 90 individuals on the Bokkeveld Plateau in western South Africa revealed head-torso lengths of 9.4 to 12.5 cm and tail lengths of 11.7 to 16 cm with a weight of 37 to 83 g. Like all elephant shrews, the Cape elephant shrews are characterized by their small body size, the relatively large head with the trunk-like elongated nose and the thin legs, with the front legs being significantly shorter than the rear legs. The fur is very soft and consists of long hair. It shows a brown-gray color on the back and on the head, which turns into an ash-gray on the sides of the trunk and on the cheeks, which can also be mottled yellowish-gray. Thus, the type is different from the sympatrically occurring Karoo Cliff elephant shrew ( Elephantulus pilicaudus ), wherein the back staining pulls down on the flanks. Light gray to whitish tones dominate on the stomach, but the hair bases are darker in color. The top of the trunk and the vibrissae are black, the chin, on the other hand, appears greyish-white. The distinctive dark circles that completely surround the large eyes in contrast to the eyes of the Karoo cliff elephant shrew and the western cliff elephant shrew ( Elephantulus rupestris ) are also of a similar light color . The ears reach a length of 25 to 33 mm and are therefore relatively large. They show rounded tips, broad bases and a well-developed tragus . Yellowish-brown spots of color appear behind the ears. The long tail is dark on the upper side in the front area, tinted lighter on the underside, the rear part is completely dark. The hairs of the dense tail fur are short, but become longer towards the back and form a thick bush at the tip. This is less clearly developed than the Karoo cliff elephant shrew or the western cliff elephant shrew. The front and rear limbs each end in five-pointed hands and feet that are armed with claws. The rear foot has lengths of 33 to 39 mm.

Skull and dentition features

The skull is between 33 and 38 mm long, at the zygomatic arches the width is 18.7 to 20.5 mm. In contrast to the western cliff elephant shrew, the tympanic bladder is slightly swollen, the bone seam between the upper jaw and the middle jawbone is largely straight. The dental formula is: . The set of teeth thus comprises 40 teeth. The upper incisors are about the same size, but the middle (I2) can also be slightly smaller. The canine shows a molar-like design. The first premolar is single-rooted and has only one tip on the chewing surface, the second premolar lacks the tongue-side cusps. The total length of the row of teeth from the first incisor to the last molar averages 18.3 mm. ${\displaystyle {\frac {3.1.4.2}{3.1.4.2}}}$

distribution

Distribution area (blue) of the Cape elephant shrew

The Cape elephant shrew is endemic to southwestern Africa . The distribution area extends from the Orange River in the northwest, where it forms the border between Namibia and South Africa , in a crescent-shaped arc along the Cape region of South Africa to approximately Port Elizabeth in the east, the size is around 130,000 km². It thus includes the western part of the South African province of North Cape , the province of Western Cape and the westernmost area of ​​the province of Eastern Cape . An originally assumed distribution gap in the Western Cape Province could not be confirmed. The populated landscapes represent the semi-desert regions of the Karoo and those of the more overgrown fynbos biozone. Overall, the Cape elephant shrew mainly inhabited by rocky-stony, sometimes sandy, habitats with little and mostly low vegetation. However, it seems to prefer areas with winter rain and a slightly more humid air, as it has not yet been proven north of the Orange River in Namibia, where much drier conditions and usually summer rain prevail. The size of the population is unknown; locally the species is not considered very common. In the Namaqua National Park in the northwestern distribution area, the population density in various biotopes could be examined. In the dry Succulent Karoo, which is characterized by rocky, dome-shaped granite hills and vegetation consisting of plant communities of mid-flowering plants , there are around 5.9 individuals per hectare . In the subsequent Renosterveld landscape area as a sub-area of ​​the fynbos with denser vegetation, which thrives on sandy-loamy soils, the density drops to 0.5 individuals per hectare. In the Riviersonderendberge mountains in the south of the Western Cape, an individual density of 2.3 to 3.0 was determined over a comparably large area. Parts of the range of the Cape elephant shrew overlap with those of the Karoo cliff elephant shrew ( Elephantulus pilicaudus ) and the western cliff elephant shrew ( Elephantulus rupestris ); it is not known whether the species actually use the same habitats.

Way of life

Territorial behavior

The Cape elephant shrew is predominantly nocturnal, but can also appear during twilight or during the day. During daytime activities, she spends the hottest phase in shady crevices in the rock. Particularly on cooler days, individual individuals also take sunbaths. The species lives ground-dwelling and can move four-footed jumping very quickly ( cursorial ). The speeds achieved are 19.4 km / h. The animals often appear alone or in pairs; like other elephants, they probably form monogamous pairs. You move in action spaces that are possibly very large. There are several shelter options in the form of crevices and crevices in the rock. Special nests are not built in these. In intra-species communication, in addition to fragrances from glands on the foot and on the back, various clicks and a cat-like "meow" are used to mark the grazing areas. A drum-like noise should also be emphasized, which is generated when the rear legs strike quickly. In the Cape elephant shrew, this foot-drumming consists of regular sequences with an interval of 30 to 50 ms, into which irregular sequences with an interval of 50 to 130 ms are also interspersed. Each drum series consists of less than ten footbeats and is rarely longer than two seconds.

nutrition

The Cape elephant shrew is largely insect- to omnivorous, most of which feed on ants and termites , as well as beetles and flies . It also consumes a larger proportion of plant material. In studies in the Namaqua National Park, the insect share in the menu was 44.25%, green plants made up a total of 28.50% and the remaining 27.25% were seeds . The insect hunt is partly done by waiting in shady crevices and then hitting it quickly. Occasionally it has been observed that the animals also seek out piles of dung from hibiscus to catch insects. More often, food is found on plants. The Cape elephant shrew functions as an important spreader of pollen , which sticks to the trunk when searching for insects and is transported further, as was observed for the sugar bushes . Evidence of pollen distribution by the elephant shrew was also provided for the parasitic plant Hyobanche and the asparagus plant Massonia bifolia . In these, the nectar of the flowers is a popular food that the animals lick off with their long tongues. According to studies in Kamiesberg , the Cape elephant shrew lingers on a single flower for up to 7.5 seconds and licks the nectar up to 28 times. The animals act as active pollinators when their noses, which are covered with pollen, touch the stigma of the flower and pass it on. The pollen can also get into the digestive tract through grooming and be transported further through the excretions. The Cape elephant shrew has not been observed actively pollen-eating, nor has it consumed any other parts of the flower.

The amount consumed daily depends on the quality and water content of the food. But it corresponds to about 22 to 38% of the body weight. As with many small mammals, the digestive time is relatively short. Some of the food can be excreted again after around 30 minutes. After about 3 hours and 18 minutes, about half of the food ingested has passed the digestive tract, after 6 hours a good 90 percent. Water is largely absorbed through food, but protein-rich food leads to a high loss of water through the urine . In order to enable a stable water balance, which is also necessary for body cooling in the sometimes clearly dry and hot climatic conditions, the urine is strongly concentrated. The body temperature of the Cape elephant shrew is very stable and averages 37.6 ° C with an outside temperature of 10 to 35 ° C. Originally it was assumed that, unlike other representatives of the elephant shrews, the species does not fall into a torpor at low ambient temperatures, which can be close to freezing in the mountains in winter . However, more recent studies show that such periods of paralysis can also occur in the Cape elephant shrew. Torpor occurs occasionally at outside temperatures below 25 ° C, but usually only lasts a few hours. From an outside temperature of below 9 ° C, the animals can remain in a state of rigidity for 24 hours up to 44 hours. The body temperature drops to almost the outside temperature, the lowest measured was 9.3 ° C. The torpor of the Cape elephant shrew is thus comparable to that of the other elephant shrew species, but on average deeper and longer. In contrast to other representatives of the elephant shrews, such as the eastern cliff elephant shrew ( Elephantulus myurus ), the torpor is used in the Cape elephant shrew even when enough food is available.

Reproduction

The offspring are usually born in the warmer and wetter season. In the western part of the distribution area the young are born between September and January, in the eastern part the reproductive period can last until February. A litter usually consists of two, rarely just one young. The young weigh between 9 and 11 g, which in the case of twin births together makes up about 36 to 43% of the weight of the mother animal. The head-trunk length of the newborn is 5.2 to 5.5 cm, the tail length 5.7 to 5.9 cm. They are born fleeing the nest and have open eyes, soft fur, broken incisors , exposed auricles and separated toes, and they can walk shortly after birth. The rate of growth is rapid, with the young gaining between 0.6 and 0.9 g per day. The young animals eat their first solid food after 12 to 16 days. After around 30 days they have reached two thirds to three quarters of the weight of the adult animals. The life expectancy of wild individuals is unknown; the maximum age for animals kept in human care is five years and eight months.

Parasites

The louse Polyplax and the ticks Ixodes , Haemaphysalis and Rhipicephalus have so far been described as external parasites . The occurrence of polyplax is rather unusual as the louse is usually associated with rodents such as Gerbilliscus .

Systematics

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

The Cape elephant shrew is a species from the genus of elephant shrews ( Elephantulus ). Nine species are currently assigned to this genus, which is quite rich in form and which are native to large parts of southern and eastern Africa . The elephantulus belong to the family of the elephant shrew (Macroscelididae) within the same order (Macroscelidea). The elephants, in turn, are a group of smaller mammals that are endemic to Africa. Today, two subfamilies can be distinguished within this group. The Rhynchocyoninae only include the proboscis dogs ( Rhynchocyon ); they are therefore to be regarded as monotypical . These largest representatives of the elephants are mainly animals adapted to densely forested habitats . The sister group are the Macroscelidinae . It includes the elephant shrews as well as the proboscis ( Petrodromus ), the North African elephant shrew ( Petrosaltator ), the Somali elephant shrew ( Galegeeska ) and the species of the genus Macroscelides . The representatives of the Macroscelidinae tend to live in drier and more open landscapes up to desert-like regions. Molecular genetic studies showed that the two subfamilies separated from each other in the Lower Oligocene about 32.8 million years ago. Within the Macroscelidinae, a greater splitting took place from the Upper Oligocene around 28.5 million years ago.

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

The molecular genetic analyzes also showed that the elephant shrews must be viewed as paraphyletic , since Petrosaltator , Petrodromus and Macroscelides are currently still deeply embedded in the genus Elephantulus . There is, however, a group of South and East African species that is well supported by genetic studies. The closest relatives of the Cape elephant shrew are the Karoo cliff elephant shrew ( Elephantulus pilicaudus ) and the eastern cliff elephant shrew ( Elephantulus myurus ), which were only newly described in 2008 ; all three form a common clade . Somewhat outside this family group there are other forms from southern Africa, such as the western cliff elephant shrew ( Elephantulus rupestris ) and the dryland elephant shrew ( Elephantulus intufi ). It is assumed that the ancestors of the species group were probably originally native to eastern Africa and that they migrated to the southwest and thus to the current areas of distribution during a phase of increasing aridization of the continent around 11.5 million years ago at the beginning of the Upper Miocene . A further desiccation of the landscape of southern Africa in the Upper Miocene in the transition to the Pliocene around 6 million years ago then led to further diversification.

Subspecies of the Cape elephant shrew are not known. From a genetic point of view, however, two subgroups can be differentiated, which are called Namaqua clade in the north and Fynbos clade further south, according to their distribution . The two groups separated about 1.7 million years ago; possibly a certain mixing occurred again after the splitting, since individual haplotypes occur together in the contact area. Reasons for the splitting of the species could lie in the changing climatic conditions of the Pleistocene , which caused fluctuating sea water levels, which led to a stronger penetration of the sea into the western coastal plains, as well as to changing river courses. In some cases, these fluctuating climatic conditions had a particularly strong impact in southwestern Africa, where during the Pleistocene there were alternately more violent wet and dry phases.

Fossil finds of the Cape elephant shrew have so far only been recovered from Saldanha Bay and Elands Bay on the west coast of South Africa. These belong to the late Young Pleistocene and are 15,540 to 13,300 years old. Some subfossil remains from the Middle Holocene have come down to us from the same region . The area of ​​discovery lies within today's distribution area.

The first scientific description of the Cape elephant shrew was in 1839 by Andrew Smith under the name Macroscelides edwardii . As a type region, Smith gave the Oliphants River in the central areas of the British Cape Colony at that time without further explanation . Gordon Barclay Corbet and John Hanks specified this in 1968 in their revision of the elephants on the Olifants River in Namaqualand , which flows towards the Atlantic, as the species is relatively widespread there, while it does not occur in the other rivers of the same name in South Africa. The species name edwardii honors Edward Verreaux, the brother of the French naturalist Jules Verreaux , who collected the holotype . In the 1950s and 1960s, the Cape elephant shrew was partially considered to be of the same species as the eastern cliff elephant shrew (which also made the Olifants River near Oudtshoorn a type area). However, numerous diagnostic dental features could be worked out to distinguish the two types. E. capensis and E. karoensis , which were established by Austin Roberts in 1924 and 1938, were used as synonymous names for Elephantulus edwardii . However, genetic studies have shown that only E. capensis belongs to the Cape elephant shrew , while E. karoensis belongs to the range of variation of the western cliff elephant shrew.

Threat and protection

The Cape elephant jumping vole is widespread, but rather rare. Nevertheless, there are no known major threats to the entire population. Habitat changes occur locally due to the expansion of human settlements, arable and pasture areas or mineral extraction, such as in the cedar mountains . This overprinting of the landscape occurs primarily in river valleys and should be viewed as rather small-scale. Due to the specialization of the species on rocky-stony subsoil, there are hardly any conflicts so far. Therefore the IUCN classifies the species as "not endangered" ( least concern ). It is represented in several nature reserves.

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. 234) ISBN 978-84-16728-08-4
• Mike Perrin and Galen B. Rathbun: Elephantulus edwardii Cape Sengi (Cape 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. 265-266
• Galen B. Rathbun: Elephantulus edwardii (A. Smith, 1839) - Cape rock elephant-shrew. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 33-34

Individual evidence

1. ^ ^{A b c d e} C. Stuart, T. Stuart and V. Pereboom: Aspects of the biology of the Cape Sengi, Elephantulus edwardii, from the Western Escarpment, South Africa. Afrotherian Conservation 2, 2003, pp. 2-4
2. ↑ ^{a b} 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
3. ↑ ^{a b c d e f} Galen B. Rathbun: Elephantulus edwardii (A. Smith, 1839) - Cape rock elephant-shrew. In: John D. Skinner and Christian T. Chimimba (Eds.): The Mammals of the Southern African Subregion. Cambridge University Press, 2005, pp. 33-34
4. ↑ ^{a b c d e f g} Mike Perrin and Galen B. Rathbun: Elephantulus edwardii Cape Sengi (Cape 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. 265-266
5. ↑ ^{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. 234) ISBN 978-84-16728-08-4
6. ↑ ^{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
7. ^ Galen B. Rathbun and Carolyn D. Rathbun: Does the Cape sengi (Elephantulus edwardii) occur in Namibia? Afrotherian Conservation 3, 2005, pp. 5-6
8. ^ ^{A b} C. Stuart, Mike Perrin, C. FitzGibbon, M. Griffin (IUCN SSC Afrotheria Specialist Group) and H. Smit (Stellenbosch University): Elephantulus edwardii. The IUCN Red List of Threatened Species. Version 2014.3. ( [1] ); last accessed on February 7, 2015
9. ^ ^{A b} M. van Deventer and J .AJ Nel: Habitat, food, and small mammal community structure in Namaqualand. Koedoe 49 (1), 2006, pp. 99-109
10. ↑ ^{a b} P. F. Woodall and GJ Currie: Food consumption, assimilation and rate of food passage in the Cape rock elephant shrew, Elephantulus edwardii (Macroscelidea: Macroscelidinae). Comparative Biochemistry and Physiology A 92, 1989, pp. 75-79
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. ↑ ^{a b} P. A. Fleming and SW Nicolson: How important is the relationship between Protea humiflora (Proteaceae) and its non-flying mammal pollinators? Oecologia 132, 2002, pp. 361-368
13. ↑ ^{a b} Belle Leon, Amiram Shkolnik and Tamar Shkolnik: Temperature regulation and water metabolism in the elephant shrew Elephantulus edwardi. Comparative Biochemistry and Physiology A 74, 1983, pp. 399-407
14. ↑ AS Faurie, ER and MR Dempster Perrin: Footdrumming patterns of southern African elephant-shrews. Mammalia 60 (4), 1996, pp. 567-576
15. ↑ Petra Wester: The forgotten pollinators - First evidence for nectar feeding by primarily insectivorous elephant-shrews: Journal of Pollination Ecology 16 (15), 2015, pp. 108-111
16. ↑ Petra Wester: Nectar feeding by the Cape rock elephant-shrew Elephantulus edwardii (Macroscelidea) - A primarily insectivorous mammal pollinates the parasite Hyobanche atropurpurea (Orobanchaceae). Flora 206, 2011, pp. 997-1001
17. ↑ Petra Wester: Sticky snack for sengis: The Cape rock elephant-shrew, Elephantulus edwardii (Macroscelidea), as a pollinator of the Pagoda lily, Whiteheadia bifolia (Hyacinthaceae). Natural Sciences 97, 2010, pp. 1107–1112
18. ↑ Fritz Geiser and Nomakwezi Mzilikazi: Does torpor of elephant shrew differentiate from other hetherothermic did of mammals? Journal of Mammalogy 92 (2), 2011, pp. 452-459
19. ↑ Edith R. Dempster, MR Perrin and RJ Nuttrall: Postnatal development of three sympatric small mammal species of southern Africa. Journal of Mammals, 57, 1992, pp. 103-111
20. ^ Gea Olbricht: Longevity and fecundity in sengis (Macroscelidea). Afrotherian Conservation 5, 2007, pp. 3-5
21. ↑ 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
22. ↑ ^{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
23. ↑ ^{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
24. ^ 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
25. ↑ Hanneline Adri Smit, Terence J. Robinson and Bettine Jansen van Vuuren: Vicariance and the endemic Cape rock sengi (Elephantulus edwardii): are these two linked? Afrotherian Conservation 5, 2007, pp. 5-7
26. ↑ ^{a b} Hanneline Adri Smit, Terence J. Robinson and Bettine Jansen van Vuuren: Coalescence methods reveal the impact of vicariance on the spatial genetic structure of Elephantulus edwardii (Afrotheria, macroscelidea). Molecular Ecology 16, 2007, pp. 2680-2692
27. ↑ Thalassa Matthews, Christiane Denysund 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
28. ↑ Patricia A. Holroyd: Past records of Elephantulus and Macroscelides: geographic and taxonomic issues. Afrotherian Conservation 7, 2009, pp. 3-7
29. ^ Andrew Smith: Illustrations of the Zoology of South Africa. Mammalia London, 1839 (Plate 14) ( [2] )

Web links

Commons : Cape elephant shrew ( Elephantulus edwardii )  - Collection of images, videos and audio files

• Elephantulus edwardii inthe IUCN Red List of Threatened Species 2014.3. Posted by: Stuart, Perrin, FitzGibbon, Griffin & Smit, 2008. Retrieved February 7, 2015.