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Saharan striped polecat

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Saharan striped polecat
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Ictonyx
Species:
I. libycus
Binomial name
Ictonyx libycus
Saharan striped polecat range
Synonyms[2]
List
  • Mustela libyca Hemprich & Ehrenberg, 1833
  • Rhabdogale multivittata Wagner, 1841
  • Ictonyx frenata Sundevall, 1843
  • Poecilictis rothschildi Thomas & Hinton, 1920

The Saharan striped polecat (Ictonyx libycus), also known as Saharan striped weasel and Libyan striped weasel, is a species of mammal in the family Mustelidae.[1]

Taxonomy and evolution

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The Saharan striped polecat was first scientifically named in 1833, when German biologists Wilhelm Hemprich and Christian Gottfried Ehrenberg reported that a species of mammal similar to the striped polecat (but differing in its patterning and smaller size) had been discovered in Libya. At the time, the striped polecat was assigned to the genus Mustela, so they assigned this new species to the same genus under the name Mustela libyca, with the specific name referencing its country of origin.[3] A separate genus named Ictonyx was later established in 1835, originally as a monotypic genus containing only the striped polecat.[4] The Saharan striped polecat would later be moved into this genus as well, being referred to as Ictonyx libyca for years, but a paper published in 2013 pointed out that because the generic name Ictonyx is masculine, the specific name should be spelled as libycus instead when this species is treated as a member of Ictonyx.[5]

The genus placement of the Saharan striped weasel has been a matter of debate among experts. The assignment of this species to Ictonyx was first contested in 1920, when British zoologists Oldfield Thomas and Martin Hinton concluded that it bears significant enough differences from the striped polecat to warrant being placed in a separate genus. They therefore erected the genus Poecilictis, of which the Saharan striped weasel became the type species, being renamed as Poecilictis libyca.[6] The name of this genus combines the Ancient Greek words "poikilos" (ποικίλος, meaning "vari-colored" or "pied") and "iktis" (ἴκτις, meaning "weasel"), in reference to the animal's black and white patterning.[2]

Many later authors would accept the usage of this genus, with American paleontologist George Gaylord Simpson using it in a book published in 1945, in addition to British naturalists John Ellerman and Terence Morrison-Scott using it in a checklist of mammals published in 1951.[7][8] On the contrary, French zoologist Pierre Louis Dekeyser and German zoologist Jochen Niethammer rejected the usage of Poecilictis in their studies published in 1950 and 1987 respectively, referring to the Saharan striped polecat as an Ictonyx species, and this classification was followed in the third edition of Mammal Species of the World published in 2005.[9][10][11] With the advancement of genetic analysis, molecular studies conducted in the 21st Century have found that assigning the Saharan striped polecat and the striped polecat as the two only species of Ictonyx would make this genus paraphyletic. This can be resolved by either adding the African striped weasel into Ictonyx (as proposed in a 2008 study) or separating the Saharan striped weasel into Poecilictis (as supported by a study published in 2012).[12][13]

Subspecies

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Several forms of the Saharan striped polecat were originally named as separate species, but are now believed to actually represent a single, highly variable species.[2] Some of these former species are now considered subspecies of the Saharan striped polecat, while others have been declared as junior synonyms of these subspecies. The following four subspecies were recognized in the third edition of Mammal Species of the World published in 2005:[11]

Subspecies Trinomial authority Description Range Synonyms
I. l. lybica

(Nominate subspecies)

Hemprich and Ehrenberg, 1833 Smaller subspecies with irregular and indistinct patterning, and a black tail tip.[6] Egypt and Libya[14] alexandrae Setzer, 1959[15]
I. l. multivittata Wagner, 1841 Variable in size, with more distinct patterns than the nominate subspecies. Tail tip may be black or white.[6] Morocco, Algeria, Tunisia, Western Sahara, central Sudan and possibly east Chad[14] frenata Sundevall, 1842[11]

vaillanti (Loche, 1856)[11]

I. l. oralis Thomas and Hinton, 1920 Larger than the nominate subspecies, with similarly indistinct patterning and black tail tip.[6] Coastal areas of Sudan[14]
I. l. rothschildi Thomas and Hinton, 1920 Small subspecies with thin fur, distinct patterning and a black tail tip. Skull more robust than that of I. l. multivittata.[16] Southwestern areas of the Sahara Desert and northern Nigeria[14]

Evolution

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The Saharan striped polecat belongs to a family of mammals known as the Mustelidae, and more specifically to a subfamily called the Ictonychinae. Members of this subfamily are split into two tribes known as Ictonychini and Lyncodontini. This species is a member of the former tribe, which also includes the striped polecat, African striped weasel and marbled polecat. Results of genetic analyses indicate that the closest living relatives of the Saharan striped polecat are the striped polecat and African striped weasel. These two species form a clade which is the sister group to the lineage whose only living species is the Saharan striped polecat.[12][13][17] A study published in 2008 suggested that the lineages of these two species diverged between 3.5 and 3 million years ago, and hypothesized that an increase in aridity was the reason it occurred.[12] However, a 2012 study proposed an earlier date between 4.8 and 4.5 million years ago for this divergence.[13] The following cladogram shows the position of the Saharan striped polecat among its closest living relatives according to Gray et al. (2022):[17]

Ictonychinae

Galictis vittata (Greater grison)

Vormela peregusna (Marbled polecat)

Ictonyx libycus (Saharan striped polecat)

Ictonyx striatus (Striped polecat)

Poecilogale albinucha (African striped weasel)

Characteristics

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The Saharan striped polecat is a small mammal, growing about 22–30 cm (9–12 in) in head-body length and weighing from 500–750 g (18–26 oz). It has a slender body with short legs, and its long tall adds an additional 12–19 cm (5–7 in) to its overall length.[18] lts fur is erectile, fluffing out when the animal is excited, which makes it look larger when it does so.[2][18] The fur consists of two main types of hair, namely a short, dense underfur and long, stout guard hairs. Hair length varies greatly between the different subspecies, and those with longer hair have a shaggy appearance.[2][14] The guard hairs on the tail are notably long, making the tail appear bushy. Like some other mustelids, this species has glands near its anus which spray a noxious fluid when it feels threatened. The head of a Saharan striped polecat bears a short snout and small ears.[14] The paws are rather narrow in form and most of the digits are spaced widely apart, though the third and fourth digits of each hind paw are closer together. Each paw has five digits and each digit bears a claw, with the front claws being longer than the hind claws. Although its two closest living relatives (the striped polecat and African striped weasel) have paws with mostly hairless undersides, those of the Saharan striped polecat differ in having thick hair on their soles. This believed to be an adaptation for the animal's sandy habitat, as are the smaller paw pads.[19]

The exact colouration and patterning varies greatly between different subspecies and populations. The limbs and undersides are black or brownish, though isolated white spots may be present.[2] In contrast, the back and flanks are mostly a much lighter colour, which may be white, buff or even orange (as observed in some Egyptian individuals). Three dark stripes generally stretch from behind the ears down the animal's back, the middle one splitting into two or three extra stripes, and merge together at the rump.[14] In some subspecies, the white guard hairs on the back are longer and partly obscure these stripes. This makes their patterning less distinct, and they appear to have spots or patches instead of stripes.[2] The face of a Saharan striped polecat bears distinctive patterns, including a white ring which goes around the mostly black face. This ring stretches under the mouth and between the eyes and ears.[14][20] The ears are black, though in some individuals their tips may be white.[20] In certain populations the snout is also black, and the area directly behind it (which bears the whiskers) is white. The facial patterns can be used to distinguish this species from the related striped polecat, in which the white facial pattern is commonly split into two cheek patches and a forehead spot.[2] The tail has variable black and white patterning, but the tip of its underside is usually black.[20]

Drawing of an animal skull from three perspectives
Illustration of the skull seen from the side (top), above (bottom left) and below (bottom right)

The skull is wide and short, with a vaguely triangular shape when viewed from above. Though absent in those of adults, the skulls of juveniles have visible sutures. In younger individuals, the sagittal crest is low and wide, and this becomes slightly higher and narrower as the animal matures.[15] Overall, the skull of this species mostly resembles that of the striped polecat, but differs in its smaller size (as the Saharan striped polecat is a smaller animal overall). The tympanic and mastoid bullae (bony structures on the underside of the skull) are proportionally much larger than those of the striped polecat, with the bullae of the two species being about the same absolute size. As the tympanic bullae contain the middle and inner ear, this may suggest the animal has a keen sense of hearing.[2][14] In addition, the mastoid and postorbital processes (projections of bone at the back of the skull and behind the eye sockets respectively) are smaller in the Saharan striped polecat.[15] The dentition of the Saharan striped polecat is similar to that of the striped polecat. In both species, the outer incisor teeth of the upper jaw are longer than the inner ones, being used alongside the canines to subdue prey. Furthermore, both have sharp carnassial teeth for shearing flesh.[14]

Illustration of the bacula of adult (a and b) and immature (c and d) males

Males of this species possess a baculum (penis bone). In one adult male, this bone measured 3.28 cm (1.29 in) in length, making it rather robust and large for the animal's size. The baculum of an adult has a wrinkled texture at its base, while its tip has a shape resembling a teardrop and is attached at a slanted angle to the shaft. The upper side of the shaft is mostly convex, with an indistinct hint of a groove where the urethra would fit into visible only near the base. In immature males, the baculum is smaller and the wrinkled texture at the base has not yet developed. Furthermore, the shape of the tip instead resembles a cup, as the bone has not yet fully formed.[21]

Distribution and habitat

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Photo of a desert with shrubs and a tree, with a mountain in the background
Semi-desert environment in southern Algeria, where the Saharan striped polecat is known to occur

Native to northern Africa, the Saharan striped polecat is known to occur around the northern and southern edges of the Sahara Desert. It is found in Mauritania, Western Sahara and Morocco in the west along the Mediterranean coast of North Africa to the Nile Valley in Egypt, while in the south its range includes the Sahel east to Sudan and Djibouti.[1] It is also known outside of the African mainland, occuring on Farwa Island in the Mediterranean Sea.[22] However, its exact distribution remains poorly understood. This species has only been researched very little compared to other small carnivorans in the region, with few studies being done on its range and habits. Furthermore, this animal is secretive in nature, and is therefore likely to be under-recorded and overlooked. This is supported by the fact that records of Saharan striped polecats have been made in recent years in locations where they were formerly unknown.[23] These include a body found near the Atlantic coast of Morocco in 2018, an individual captured in southern Algeria in 2020, and multiple sightings from Tunisia throughout the early 21st Century.[23][24][25]

The Saharan striped polecat prefers steppe-like environments and lives on the margins and mountains of the Sahara desert. Arid, rocky terrain and sandy semi-deserts are its preferred habitat, but it does rarely occur in woodlands.[18] Oases and cultivated areas are also known habitats for this species. Most areas it inhabits have only sparse or very sparse plant cover, with the majority of this being made up of small bushes. It is most often found in dry areas where the annual rainfall is below 15 cm (6 in), apart from in coastal dunes where this can reach 25 cm (10 in). However, it does not inhabit the driest areas of the central Sahara.[14]

Behaviour and ecology

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Saharan striped polecat

The Saharan striped polecat is nocturnal animal, with activity beginning at dusk. It hides during the day in burrows, capable of digging simple tunnels in the soil using its claws, though it also uses burrows made by other animals.[20] One burrow made by this species in Niger measured about 3 m (10 ft) in length and reached a depth of 70 cm (28 in) below the surface, with a small chamber at its end.[14] Aside from burrows, rock crevices are also used as shelter. This animal moves about at night in the open in a slow, deliberate way, with its tail held vertically. In the wild, it is a mostly solitary species.[18] However, pairs can reportedly be kept together in captivity without exhibiting aggression towards each other. Though the Saharan striped polecat lives predominantly on the ground, it is capable of climbing branches or the wire netting of cages.[26] It is known to spray a foul, skunk-like anal emission when threatened.[27] Before releasing the anal emission, it raises its fur in an attempt to warn the potential attacker.[20]

Diet and hunting

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Like other mustelids, this species is a predatory animal. Lizards are its main prey, making up most of its diet.[20] An individual from Wadi El Natrun, Egypt captured in 1903 reportedly had a preference for eating these reptiles over all other food.[28] In addition, it also feeds on eggs, birds, insects and small mammals, with rodents of the genus Gerbillus being the most commonly taken mammalian prey. It sometimes preys on poultry according to local people.[14] It can feed on small amounts of plant matter in captivity, as evidenced by a pair kept in Poznań Zoo, Poland which were fed grated vegetables, boiled cereals and seeds along with chopped meat. However, this pair was noted to reject fruit.[26] Much of this animal's prey is tracked down by scent and dug out of burrows, and although it normally moves slowly, it can move quite rapidly and pounce quickly when pursuing prey.[18] When making a kill, it bites into the back of the prey's skull.[14] Due to its high metabolic rate, this animal must feed frequently and can only exist in areas with high prey density.[23]

Reproduction

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Although the mating season of this animal is not precisely known, it is likely variable. Sightings of young individuals have been reported in the months of April, August and November.[14] The gestation period may be as short as 37 days, which is exceptionally short for a carnivoran, but could also be as long as 11 weeks.[2] After this, the mother generally gives birth to a litter of one to three young in spring.[20] The newborns are altricial, with their eyes closed but ears open, and have very short whitish fur. One pair bred in captivity weighed only 5 g (0.18 oz) each at birth, with body lengths of just 6.3 cm (2 in).[26] Birth takes place inside a chamber at the end of a burrow, which is left unlined such that the young are born onto the soil directly. The distinctive dark patterns of this species develop at an age of three weeks, and the eyes open about half a week after that.[2] At five weeks old, the young begin to eat solid food. The mother carries her young by the neck, doing so until they reach two months of age, and another month later the mother and young separate. Females are capable of having another litter as soon as 40 days after the previous litter was born, with one captive female doing so after her first litter died early.[26]

Threats

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In Tunisia, Saharan striped polecats are often caught and exploited because of the tribal belief that they may increase male fertility.[1]

References

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  1. ^ a b c d Ahmim, M.; Do Linh San, E. (2015). "Ictonyx libycus". IUCN Red List of Threatened Species. 2015: e.T41645A45212347. doi:10.2305/IUCN.UK.2015-4.RLTS.T41645A45212347.en. Retrieved 15 November 2021.
  2. ^ a b c d e f g h i j k Rosevear, Donovan Reginald (1974). The carnivores of West Africa. London : Trustees of the British Museum (Natural History). pp. 104–110.
  3. ^ Ehrenberg, Christian Gottfried; Hemprich, Wilhelm Friedrich (1833). Symbolae physicae, seu, Icones et descriptiones corporum naturalium novorum aut minus cognitorum : quae ex itineribus per Libyam Aegyptum Nubiam Dongalam Syriam Arabiam et Habessiniam publico institutis sumptu Friderici Guilelmi Hemprich et Christiani Godofredi Ehrenberg : studio annis MDCCCXX-MDCCCXXV redierunt (in Latin). Smithsonian Libraries. Berolini : Ex Officina Academica, venditur a Mittlero.
  4. ^ Kaup, Johann Jakob (1835). Das Thierreich in seinen Hauptformen systematisch beschrieben. Darmstadt: Diehl. pp. 352–353.
  5. ^ Do Linh Sam, Emmanuel; Ferguson, Adam W.; Belant, Jerrolt L.; Schipper, Jan; Hoffmann, Michael; Gaubert, Philippe; Angelici, Francesco M.; Somers, Michael J. (2013). "Conservation status, distribution and species richness of small carnivores in Africa". Small Carnivore Conservation. 48: 4–18. S2CID 85630388.
  6. ^ a b c d Thomas, Oldfield; Hinton, Martin (1920). "On the group of African Zorils represented by Ictonyx libyca". The Annals and magazine of natural history; zoology, botany, and geology. 5: 367–369. doi:10.1080/00222932008632388.
  7. ^ Simpson, George Gaylord (1945). "The principles of classification and a classification of Mammals". Bulletin of the AMNH. 85: 1–350.
  8. ^ Ellerman, John Reeves; Morrison-Scott, Terence Charles Stuart (1951). Checklist of Palaearctic and Indian mammals 1758 to 1946. London: Trustees of the British Museum. pp. 267–268.
  9. ^ Dekeyser, Pierre Louis (1950). "Considérations sur les chats (Felis libyca Forster) de I'Afrique occidentale". Bulletin de l'Institut Française d'Afrique Noire (in French). 12: 700–709.
  10. ^ Niethammer, Jochen (1987). "Das Streifenwiesel (Poecilictis libyca) im Sudan und seine Gesamtverbreitung". Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. 38: 173–182.
  11. ^ a b c d Wozencraft, W. C. (2005). "Ictonyx lybica". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 532–628. ISBN 978-0-8018-8221-0. OCLC 62265494.
  12. ^ a b c Koepfli, Klaus-Peter; Deere, Kerry A; Slater, Graham J; Begg, Colleen; Begg, Keith; Grassman, Lon; Lucherini, Mauro; Veron, Geraldine; Wayne, Robert K (2008). "Multigene phylogeny of the Mustelidae: Resolving relationships, tempo and biogeographic history of a mammalian adaptive radiation". BMC Biology. 6 (1): 10. doi:10.1186/1741-7007-6-10. ISSN 1741-7007. PMC 2276185. PMID 18275614.
  13. ^ a b c Sato, Jun J.; Wolsan, Mieczyslaw; Prevosti, Francisco J.; D’Elía, Guillermo; Begg, Colleen; Begg, Keith; Hosoda, Tetsuji; Campbell, Kevin L.; Suzuki, Hitoshi (2012). "Evolutionary and biogeographic history of weasel-like carnivorans (Musteloidea)". Molecular Phylogenetics and Evolution. 63 (3): 745–757. Bibcode:2012MolPE..63..745S. doi:10.1016/j.ympev.2012.02.025. hdl:11336/67833. ISSN 1055-7903. PMID 22410652.
  14. ^ a b c d e f g h i j k l m n o Kingdon, Jonathan (2014-11-20). Mammals of Africa: Volume V: Carnivores, Pangolins, Equids and Rhinoceroses. A&C Black. pp. 90–92. ISBN 978-1-4081-8994-8.
  15. ^ a b c Osborn, Dale J.; Helmy, Ibrahim (1980). The contemporary land mammals of Egypt (including Sinai). Chicago: Field Museum of Natural History. pp. 395–404.
  16. ^ "Captain Angus Buchanan's Air Expedition. 1. On a series of small mammals from Kano". Novitates Zoologicae. 27: 315–320. 1920. doi:10.5962/bhl.part.7305. ISSN 0950-7655.
  17. ^ a b Gray, Autumn; Brito, José C.; Edwards, Cody W.; Figueiró, Henrique V.; Koepfli, Klaus-Peter (2022-11-02). "First complete mitochondrial genome of the Saharan striped polecat (Ictonyx libycus)". Mitochondrial DNA Part B. 7 (11): 1957–1960. doi:10.1080/23802359.2022.2141080. ISSN 2380-2359. PMC 9665073. PMID 36386018.
  18. ^ a b c d e Kingdon, J. (1997). The Kingdon Field Guide to African Mammals. Academic Press. p. 229. ISBN 978-0-12-408355-4.
  19. ^ Pocock, R. I. (1921). "On the External Characters and Classification of the Mustelidae". Proceedings of the Zoological Society of London. 91 (4): 803–837. doi:10.1111/j.1096-3642.1921.tb03292.x. ISSN 0370-2774.
  20. ^ a b c d e f g Hoath, R. (2009). A Field Guide to the Mammals of Egypt. Egypt: The American University in Cairo Press. pp. 82–84. ISBN 9789774162541.
  21. ^ Setzer, Henry W. (1960-02-20). "The baculum of Poecilictis libyca". Journal of Mammalogy. 41 (1): 138–139. doi:10.2307/1376543. ISSN 0022-2372.
  22. ^ Jdeidi, Tarek Basher Mohamed; Saed, Fauzi Ahmed; Elhosk, Mohamed Abdullah (2018). "The Main Fauna and Flora of Farwa Island". Atti e Memorie dell'Ente Fauna Siciliana. 12: 171–176. ISSN 1974-3645.
  23. ^ a b c Cherkaoui, Sidi Imad (2020). "New Record of the Libyan Striped Weasel Ictonyx libycus from the Atlantic Moroccan Sahara". Small Carnivore Conservation. 58.
  24. ^ Moussouni, Abdenour; Scaravelli, Dino (2024). "New records of Libyan striped weasel Ictonyx libycus and common genet Genetta genetta from the Algerian Sahara". Small Carnivore Conservation. 62.
  25. ^ El-Farhati, Haithem; Nouira, Saïd (2022). "New records of the Libyan striped weasel Ictonyx libycus in Tunisia". African Journal of Ecology. 60 (4): 1257–1261. doi:10.1111/aje.13037. ISSN 1365-2028.
  26. ^ a b c d Sitek, Hanna (1995). "Breeding of the Libyan striped weasel Poecilictis libyca at Poznan Zoo, Poland". Small Carnivore Conservation. 13: 8–9.
  27. ^ Newman, C.; Buesching, C.D. & Wolff, J.O. (2005). "The function of facial masks in midguild carnivores" (PDF). Oikos. 108 (3): 623–633. doi:10.1111/j.0030-1299.2005.13399.x. JSTOR 3548808.
  28. ^ de Winton, William Edward (1903). "List of mammals obtained by the Hon. N. Charles Rothschild and the Hon. Francis R. Henley in the Natroun Valley, Egypt". Novitates Zoologicae. 10: 279–285.
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