Dark elephant dog

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Dark elephant dog
Dark elephant dog (Rhynchocyon stuhlmanni)

Dark elephant dog ( Rhynchocyon stuhlmanni )

Systematics
Superordinate : Afrotheria
without rank: Afroinsectiphilia
Order : Elephant jerk (Macroscelidea)
Family : Elephant jerk (Macroscelididae)
Genre : Proboscis Dog ( Rhynchocyon )
Type : Dark elephant dog
Scientific name
Rhynchocyon stuhlmanni
Matschie , 1893

The dark elephant dog ( Rhynchocyon stuhlmanni ) is a species of mammal from the family of elephants (Macroscelididae). It occurs mainly in Central Africa , where it inhabits the tropical rainforests of the Congo Basin . Like all elephants, the species is characterized by its trunk-like, elongated nose and slender limbs, with the hind legs being longer than the front legs. The color of the fur is variable and ranges from lighter to darker brown tones, the spotted stripes on the back appear characteristic. Little information is available about the way of life of the dark elephant. The species was scientifically introduced in 1893. In the second half of the 20th century and at the beginning of the 21st century, the dark elephant dog was considered a subspecies of the spotted elephant dog , genetic studies from 2017 show it to be independent again.

features

Habitus

The dark proboscis dog reaches about the dimensions of the spotted proboscis dog ( Rhynchocyon cirnei ). Based on over 60 examined individuals, which are kept in the American Museum of Natural History , the total length varies from 18 to 21 inches. The tail takes from 22.3 to 26.5 cm. Two animals from the northeastern Congo Basin examined had a total length of 49.8 and 55.5 cm, a tail length of 23.5 and 24.7 cm and a weight of 425 and 450 g. The physique is comparable with the other proboscis dogs with the trunk-like elongated nose and the short front and long rear legs. The coat color varies greatly and obviously shows regional clinical adaptations. Animals from the western area of ​​distribution are predominantly yellowish-brown in color on the back, while in the central-north, for example in the area of ​​the Ituri forest, they appear very blackish brown. In the west, on the other hand, lighter brownish gray tinted individuals dominate. The pattern of the back fur, which the dark trunk dog has in common with the spotted trunk dog, is striking. It consists of six dark stripes, which are difficult to see in dark individuals. The two median strips are very spotty and at the front end significantly narrower than in some representatives of the spotted elephant. The second row is short and the third is barely visible. The underside is mostly light, creamy yellow-brown, in darker animals this color is often narrowed to a narrow stripe. The tail usually has a whitish color, sometimes it is light brown on top. The head is colored similar to the back. The ears are erect, their length is 25 to 33 mm. The feet are always black in color, the hind foot length ranges from 81 to 91 mm. Both the front and rear feet each have four rays with powerful claws.

Skull and dentition features

The length of the skull varies between 62.2 and 71.1 mm, the width at the zygomatic arch between 33.5 and 38.1 mm. The very short nasal bone , which only reaches about 13% of the total length of the skull, is striking . The bit consists of 34 to 36 teeth with the following tooth formula : . The upper incisor , like the other proboscis dogs, is either small or not at all. There is a noticeable secondary sexual dimorphism on the upper canine : in females this becomes 3.7 to 6.9 mm long, in males 5.7 to 7.5 mm. The length of the upper row of teeth varies between 25.7 and 29.0 mm.

distribution and habitat

Distribution area of ​​the dark proboscis dog

The distribution area of ​​the dark proboscis dog includes the northern and eastern Congo Basin between the Congo and Ubangi rivers in the north and east of the Democratic Republic of the Congo . A previously unconfirmed observation comes from near Bangui in the Central African Republic and would be the only evidence west of the Ubangi. In the east, the occurrence extends to Uganda , but here the populations are rather spotty, such as in the Budongo forest on Lake Albert or in the Mabira forest on Lake Victoria . In general, the species inhabits dense tropical rainforests with closed forest covers. The Congo was in old secondary forests with limited undergrowth and plant communities of arrowroot plants and Sapele registered inventories directly.

Way of life

Little information is available about the way of life of the dark elephant. The animals are solitary and build nests from plant material that is brought in from the environment. The nests are made in round recesses in the ground. In search of food, they dig small holes in the ground with their snouts. The food consists of insects ; some of the stomach contents examined mainly contained ants . Like other representatives of the proboscis, the animals do not create any paths on their migrations. Based on around two dozen individuals captured in the Congo in the northeast of the Congo Basin, the ratio of males to females is around 1: 1. Pregnant females were mainly observed in the dry season, and one female examined carried two fetuses . The African golden cat is an important predator . According to analyzes of excrement residues in the Ituri forest in the northeast of the Congo Basin , the dark proboscis pooch accounts for around 7.1% of the prey consumed. Endangered animals freeze first and then flee to the next hiding place. On the run they reach high speeds, but do not jump on their hind legs, but walk on four feet. Fleas of the genus Chimaeropsylla and two-winged fleas of the genus Cordylobia are known to be external parasites .

Systematics

Internal systematics of elephants according to Heritage et al. 2020
 Macroscelididae  
  Macroscelidinae  
  Macroscelidini  


 Galegeeska


   

 Petrodromus


   

 Petrosaltator




   

 Macroscelides



  Elephantulini  

 Elephantulus



  Rhynchocyoninae  

 Rhynchocyon



Template: Klade / Maintenance / Style

The dark proboscis is a species from the genus of the proboscis dog ( Rhynchocyon ), which consists of a total of five species. The elephants in turn form part of the family of elephants (Macroscelididae) within the order of the same name (Macroscelidea). The elephants are smaller mammals that are endemic to Africa . They consist of six genera in two subfamilies. The subfamily of the Rhynchocyoninae is monotypical and includes only the proboscis dogs, which at the same time represent the largest forms of the elephants. They prefer closed, wooded habitats . The second subfamily, the Macroscelidinae , includes the elephant shrews ( Elephantulus ), the proboscis ( Petrodromus ) and the genera Macroscelides , Galegeeska and Petrosaltator . The species in this group are characterized by their significantly smaller growth, and they also inhabit predominantly dry to sometimes desert-like landscapes. Molecular genetic studies revealed a separation of the two subfamilies in the Lower Oligocene about 32.8 million years ago. Greater diversification within the genus Rhynchocyon began in the late Middle Miocene , about 9.7 million years ago.

Internal systematics of the proboscis dogs according to Carlen et al. 2017
 Rhynchocyon  

 Rhynchocyon chrysopygus


   


 Rhynchocyon stuhlmanni


   

 Rhynchocyon cirnei



   

 Rhynchocyon udzungwensis


   

 Rhynchocyon petersi





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The dark elephant was first scientifically described in 1893 by Paul Matschie . For this purpose, Matschie had two individuals available, an adult and a young female. The adult had a body length of 24 and a tail length of 22.1 cm. Both specimens come from the area around Andundi on the Semliki River west of the Ruwenzori Mountains in present-day Uganda , which is considered a type locality. They were picked up by Franz Stuhlmann during an expedition , and Matschie also gave him the specific epithet in his honor . Thirteen years later, Richard Lydekker established the subspecies Rhynchocyon stuhlmanni nudicaudata using animals from the Ituri forest in the northeast of the Democratic Republic of the Congo . With their dark fur color, these largely corresponded to the specimens described by Matschies, but had bare tails and ear bases, the subspecies name refers to the former. Oldfield Thomas and Robert Charles Wroughton introduced a further form with Rhynchocyon claudi in 1907. It differed from the dark elephant dog in that it was generally lighter in color. The species was named after Claud Alexander , who led the Alexander Gosling Expedition until 1904 (the leadership was later taken over by his brother Boyd Alexander ), during which four specimens were caught on the Uelle River in the north of the Democratic Republic of the Congo. Later, the form with Rhynchocyon stuhlmanni claudi was also listed as a subspecies of the dark proboscis dog. Both names, both Rhynchocyon stuhlmanni nudicaudata and Rhynchocyon stuhlmanni claudi , are now synonymous with the dark elephant dog.

In its first description, Matschie referred the dark elephant dog due to the distinctive coat pattern in the vicinity of the spotted elephant dog ( Rhynchocyon cirnei ), but recognized it as a separate species. The status quo remained in place for the near future . It was not until 1968 that Gordon Barclay Corbet and John Hanks arranged all of the elephants with spotty back fur into a single species, making the dark elephant just one of six subspecies of the spotted elephant. However, in their general overhaul of the elephant, they noted that the dark elephant might still be granted a species status, which in the opinion of the authors, in addition to the darker coat markings and the shorter nasal bone, would also be supported by the separate area of ​​distribution. Almost half a century later, in 2017, this view was confirmed in a molecular genetic study. Accordingly, the genetic distance between the five other subspecies of the spotted elephant dog is between 1 and 1.6%, while it is around 2% to the dark elephant dog. In addition, the latter has deviating alleles in the core DNA , which means that there are not only geographical and morphological but also genetic differences to the spotted elephant. For these reasons, the authors of the study again raised the dark proboscis to the species rank.

Threat and protection

The IUCN does not currently have the dark elephant. In the distribution area, the species is sometimes hunted as a food resource, for example the Mbuti pygmies in the Ituri forest in the Congo Basin chase the animals.

literature

  • Elizabeth J. Carlen, Galen B. Rathbun, Link E. Olson, Christopher A. Sabuni, William T. Stanley and John P. Dumbacher: Reconstructing the molecular phylogeny of giant sengis (Macroscelidea; Macroscelididae; Rhynchocyon). Molecular Phylogenetics and Evolution 113, 2017, pp. 150-160 doi: 10.1016 / j.ympev.2017.05.012
  • 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. 227–228) ISBN 978-84-16728-08-4

Individual evidence

  1. ↑ a b c d J. A. Allen: The American Museum Congo expedition collection of Insectivora. Bulletin of the American Museum of Natural History 47, 1922, pp. 1–38 ( [1] )
  2. ↑ Consolate K. Kaswera: Characteristics of Elephant-shrews along the Congo river. Kisangani University, 2010
  3. ↑ a b c d e 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
  4. ↑ a b Francesco Rovero, Galen B. Rathbun, A. Perkin, T. Jones, DO Ribble, C. Leonard, RR Mwakisoma and N. Doggart: A new species of giant sengi or elephant-shrew (genus Rhynchocyon ) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. Journal of Zoology 274 (2), 2008, pp. 126-133
  5. ^ 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)
  6. ↑ 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. 227–228) ISBN 978-84-16728-08-4
  7. ^ A b c J. Clevedon Brown: Observations on the Elephant shrews (Macroscelididae) of equatorial Africa. Proceedings of the Zoological Society of London 143, 1964, pp. 103-119
  8. ↑ a b Consolate K. Kaswera: The ecology and morphology of sengis in DRC. Afrotherian Conservation 6, 2008, pp. 11-12
  9. ↑ a b Galen B. Rathbun: Rhynchocyon cirnei Checkered Giant Sengi (Checkered 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. 285-286
  10. ↑ John A. Hart, M. Katembo and K. Punga: Diet, prey selection and ecological relations of leopard and golden cat in the Ituri forest, Zaire. African Journal of Ecology 34, 1996, pp. 364-379
  11. ↑ 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
  12. ↑ 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
  13. ^ 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
  14. ^ HA Smit, B. 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
  15. ↑ a b Elizabeth J. Carlen, Galen B. Rathbun, Link E. Olson, Christopher A. Sabuni, William T. Stanley and John P. Dumbacher: Reconstructing the molecular phylogeny of giant sengis (Macroscelidea; Macroscelididae; Rhynchocyon). Molecular Phylogenetics and Evolution 113, 2017, pp. 150-160
  16. ↑ Paul Matschie: About two monkeys described by Schreber and about some apparently new mammals from Africa. Meeting reports of the Society of Friends of Nature Research in Berlin 1893, pp. 60–68 ( [2] )
  17. ↑ Paul Matschie: The mammals of German East Africa. Berlin, 1895, pp. 1–157 (p. 31) ( [3] )
  18. ^ Richard Lydekker: Descriptions of two mammals from the Ituri Forest. Proceedings of the Zoological Society of London 1906, pp. 992-996 ( [4] )
  19. ↑ Oldfield Thomas and Robert Charles Wroughton: New mammals from the Lake Chad and the Congo, mostly from the collections made during the Alexander-Gosling Expedition. Annals and Magazin of Natural History 7 (19), 1907, pp. 370–387 ( [5] )
  20. ^ RE Moreau, GHE Hopkins and RW Hayman: The Type-Localities of some African Mammals. Journal of Zoology 115 (3/4), 1946, pp. 387-447
  21. ^ Giuseppe M. Carpaneto and Francesco P. Germi: The mammals in the zoological culture of the Mbuti pygmies in North-Eastern Zaire. Hystrix NS 1, 1989, pp. 1-83