Overview

Distribution

Range Description

This species is found in Brunei, Indonesia (Kalimantan Borneo, Belitung and Banka), Malaysia (Sabah and Sarawak Borneo) and the Philippines (Tawi Tawi, Bongao, Sangasanga, and perhaps some other small islands in the Sulu Archipelago) (Fooden 1991; Timm and Birney 1992). Ethnographic survey records suggest local extinction in some islands in the Tawi Tawi group (Philippines), though the species is still likely to be found on smaller islands (Garcia pers. comm. 2006).
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Physical Description

Type Information

Type for Nycticebus menagensis
Catalog Number: USNM 142234
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Male; Adult
Preparation: Skin; Skull
Collector(s): W. Abbott
Year Collected: 1905
Locality: Sanggau District, along the Sakaiam River [= Sungai Sekayam], a tributary of the Kapuas River [= Sungai Kapuas], Borneo, Kalimantan Barat, Indonesia, Asia
  • Type: Lyon, M. W. 1906 Nov 09. Proceedings of the United States National Museum. 31: 535.
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Type for Nycticebus menagensis
Catalog Number: USNM 124907
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Female; Adult
Preparation: Skin; Skull
Collector(s): W. Abbott
Year Collected: 1904
Locality: Banka Island [= Pulau Bangka], W side Klabat Bay [= Teluk Klabat], Sumatra, Kepulauan Bangka Belitung, Indonesia, Asia
  • Type: Lyon, M. W. 1906 Nov 09. Proceedings of the United States National Museum. 31: 536.
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
The species occurs in primary and secondary lowland forest, gardens, and plantations (Payne et al. 1985; Timm and Birney 1992), at elevations between 35-100 m. According to interviews with local people in the Philippines, the species tends to be sighted in citrus trees (calamansi) (Garcia pers. comm. 2006) and may be tolerant of a variety of habitats. It is nocturnal, and almost entirely arboreal. In Sabangau National Park, of four sightings of lorises, 50% contained two or more individuals, feeding together in the same tree (Callophylum hosei and Szygium cf. nigricans).

Systems
  • Terrestrial
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
VU
Vulnerable

Red List Criteria
A2cd+3cd

Version
3.1

Year Assessed
2008

Assessor/s
Nekaris, A. & Streicher, U.

Reviewer/s
Mittermeier, R.A. & Rylands, A.B. (Primate Red List Authority)

Contributor/s

Justification
Listed as Vulnerable as there has probably been more than a 30% reduction in population over three generations (approximately 21-24 years) based on harvesting for the pet trade and extensive habitat loss.

History
  • 2000
    Data Deficient
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Population

Population
Based on data collected from researchers in the field and old specimens from museum collections, Meijaard et al. (2005) claimed that this species is common throughout Borneo. However, loris ?presence? is usually not determined first-hand (Chivers and Burton 1988; Indrawan and Rangkuti 2001), and it also cannot be presumed that lorises still occur in areas from where they were once collected. The species actually seems to be very uncommon throughout its range. It has a very limited distribution in the Philippines (Dagosto and Gebo 1995; Heaney et al. 1998). In Kalimantan, a 3-month survey in a protected peat swamp forest (Sabangau National Park) revealed very low densities of slow lorises, 0.21 - 0.38 animals/km (Nekaris et al. in review). When comparing this to other studies of Nycticebus, it seems clear that this species, when it does occur, is rare. Indeed, in 46,000 trapping nights in Kinabalu National Park, Wells et al. (2004) trapped this species only 3 times, and noted that in nocturnal walks over five years, it was rarely seen.

Population Trend
Decreasing
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Threats

Major Threats
Burning of habitat and conversion, especially to palm oil plantations, almost certainly represents a threat to this species. Although it is relatively adaptable to anthropogenic habitats, and so it might less affected by forest loss than some other primate species, forest loss has been so severe in the region that it is likely to have had some negative impacts. The species is collected locally for use as pets; subsequent uncontrolled release of pets in some areas is also a threat.
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Management

Conservation Actions

Conservation Actions
This species is included in Appendix I of CITES and is protected by Indonesian law. Surveys to study the status of all populations, including those from the Philippines and other small Indonesian islands are required. Some forest fragments where the species occur remain protected. There is a particular need for field guides for this and other nocturnal Indonesian primate species, as they are often confused in rescue centers and elsewhere. The species occurs in a number of protected areas throughout its range, though its status there is uncertain (Nekaris et al. 2008).
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Wikipedia

Nycticebus borneanus

Nycticebus borneanus is a strepsirrhine primate and a species of slow loris that is native to central south Borneo in Indonesia. Formerly considered a subspecies or synonym of the Bornean slow loris (N. menagensis), it was promoted to full species status in 2013 when a study of museum specimens and photographs identified distinct facial markings, which helped to differentiate it as a separate species. It is distinguished by its dark, contrasting facial features, as well as the shape and width of the stripes of its facial markings.

As with other slow lorises, this arboreal and nocturnal species primarily eats insects, tree gum, nectar, and fruit and has a toxic bite, a unique feature among primates. Although not yet evaluated by the International Union for Conservation of Nature (IUCN), it is likely to be listed as "Vulnerable" or placed in a higher-risk category when its conservation status is assessed. It is primarily threatened by habitat loss and the illegal wildlife trade.

Taxonomy and phylogeny[edit]

N. borneanus is a strepsirrhine primate, and species of slow loris (genus Nycticebus) within the family Lorisidae. Museum specimens of this animal had previously been identified as the Bornean slow loris (Nycticebus menagensis), first described by the English naturalist Richard Lydekker in 1893 as Lemur menagensis.[2] In 1906, Marcus Ward Lyon, Jr. first described N. borneanus from western Borneo.[3] By 1953, all of the slow lorises were lumped together into a single species, the Sunda slow loris (Nycticebus coucang).[4] In 1971, that view was updated by distinguishing the pygmy slow loris (N. pygmaeus) as a species, and by further recognizing four subspecies, including N. coucang menagensis, the Bornean slow loris.[5][6] From then until 2005, N. borneanus was considered a synonym of the Bornean slow loris,[7] which was elevated to the species level (as N. menagensis) in 2006, when molecular analysis showed it to be genetically distinct from N. coucang.[8]

A 2013 review of museum specimens and photographs attributed to N. menagensis resulted in elevating two of its former subspecies to the species N. bancanus and N. borneanus.[9] Additionally, N. kayan emerged as a new species, which had previously been overlooked. All newly recognized or elevated species showed significant differences in their "face mask"—the coloration patterns on their face.[9]

Physical description[edit]

Like other slow lorises, it has a vestigial tail, round head, and short ears.[10] It has a rhinarium (the moist, naked surface around the nostrils of the nose) and a broad, flat face with large eyes.[11] Like N. menagensis, this and all other Bornean species lack a second upper incisor, which distinguishes them from other slow lorises.[12] On its front feet, the second digit is smaller than the rest; the big toe on its hind foot opposes the other toes, which enhances its gripping power. Its second toe on the hind foot has a curved grooming claw that it uses for scratching and grooming, while the other nails are straight.[11] It also possesses a specialized arrangement of lower front teeth, called a toothcomb, which is also used for grooming, as with other lemuriform primates.[13] On the ventral side of its elbow, it has a small swelling called the brachial gland, which secretes a pungent, clear oily toxin that the animal uses defensively by wiping it on its toothcomb.[14]

The facial markings of N. borneanus are dark and contrasting. The dark rings around its eyes are usually rounded on top, though sometimes diffuse-edged, and they never reach below the zygomatic arch. The stripe between the eyes often varies in width, the ears are covered in hair, and the band of hair in front of the ears is wide. The colored patch on the top of the head is usually round, but is sometimes a narrower band. The body length averages 260.1 mm (10.24 in) for the species.[12]

Distribution[edit]

N. borneanus is found in central south Borneo, in the Indonesian provinces of West, South, and Central Kalimantan. Its range extends south of the Kapuas River and east to the Barito River. However, N. borneanus is not found in the extreme southwest of the island. It may be sympatric with N. bancanus in the province of West Kalimantan.[15]

Habitat and ecology[edit]

Like other slow lorises, N. borneanus is arboreal, nocturnal,[10] and omnivorous, eating primarily insects, tree gum, nectar, and fruit.[16] Likewise, this species has a toxic bite, a unique feature found only in slow lorises among primates. The toxin is produced by licking a brachial gland (a gland by their elbow), and the secretion mixes with its saliva to activate. Their toxic bite is a deterrent to predators, and the toxin is also applied to the fur during grooming as a form of protection for their infants. When threatened, slow lorises may also lick their brachial glands and bite their aggressors, delivering the toxin into the wounds. Slow lorises can be reluctant to release their bite, which is likely to maximize the transfer of toxins.[17]

The face mask may help the species identify potential mates by distinguishing species, and may serve as an anti-predator strategy by making its eyes appear larger than they really are.[18]

Conservation[edit]

While this new species has yet to be assessed by the IUCN, N. menagensis was listed as "Vulnerable" as of 2012.[9] Because that species has been divided into four distinct species, each of the new species faces a higher risk of extinction. Accordingly, each of them are expected to be listed as "Vulnerable" at the least, with some of them likely to be assigned to a higher-risk category.[19]

Between 1987 and 2012, one-third of Borneo's forests have been lost, making habitat loss one of the greatest threats to the survival of N. borneanus. The illegal wildlife trade is also a major factor,[9] with loris parts commonly sold in traditional medicine and viral videos on YouTube promoting the exotic pet trade.[19][20][21] However, all slow loris species are protected from commercial trade under Appendix I of CITES.[22]

References[edit]

  1. ^ "Appendices I, II and III" (PDF). Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2010. 
  2. ^ Munds, Nekaris & Ford 2013, p. 46.
  3. ^ Lyon, Jr. 1906, pp. 535–536.
  4. ^ Osman Hill 1953, pp. 156–163.
  5. ^ Groves 1971.
  6. ^ Groves 2001, p. 99.
  7. ^ Groves 2005, p. 122.
  8. ^ Chen et al. 2006, p. 1198.
  9. ^ a b c d Munds, Nekaris & Ford 2013, p. 47.
  10. ^ a b Ankel-Simons 2007, p. 82.
  11. ^ a b Smith & Xie 2008, pp. 159–160.
  12. ^ a b Munds, Nekaris & Ford 2013, p. 53.
  13. ^ Ankel-Simons 2007, p. 246.
  14. ^ Hagey, Fry & Fitch-Snyder 2007, p. 253.
  15. ^ Munds, Nekaris & Ford 2013, p. 52–53.
  16. ^ Nekaris & Bearder 2007, pp. 28–33.
  17. ^ Alterman 1995, pp. 421–423.
  18. ^ Munds, Nekaris & Ford 2013, p. 49.
  19. ^ a b Wall, T. (13 December 2012). "Three new species of venomous primate identified by MU researcher". Missouri University News Bureau. Archived from the original on 24 December 2012. Retrieved 19 December 2012. 
  20. ^ Bryner, J. (14 December 2012). "Slow loris species, Nycticebus kayan, discovered in Borneo". The Huffington Post. Archived from the original on 4 January 2013. Retrieved 15 December 2012. 
  21. ^ Walker, M. (13 December 2012). "Primate species: new slow loris found in Borneo". BBC News. Archived from the original on 24 December 2012. 
  22. ^ Nekaris & Munds 2010, p. 390.

Literature cited[edit]

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Nycticebus bancanus

Nycticebus bancanus is a strepsirrhine primate and a species of slow loris that is native to southwestern Borneo and the island of Bangka. Originally considered a subspecies or synonym of the Bornean slow loris (N. menagensis), it was promoted to full species status in 2013 when a study of museum specimens and photographs identified distinct facial markings, which helped to differentiate it as a separate species. It is distinguished by the crimson red fur on its back, light-colored facial features, as well as the shape and width of the stripes of its facial markings.

As with other slow lorises, this arboreal and nocturnal species primarily eats insects, tree gum, nectar, and fruit and has a toxic bite, a unique feature among primates. Although not yet evaluated by the International Union for Conservation of Nature (IUCN), it is likely to be listed as "Vulnerable" or placed in a higher-risk category when its conservation status is assessed. It is primarily threatened by habitat loss and the illegal wildlife trade.

Taxonomy and phylogeny[edit]

N. bancanus is a strepsirrhine primate, and species of slow loris (genus Nycticebus) within the family Lorisidae. Museum specimens of this animal had previously been identified as the Bornean slow loris (Nycticebus menagensis), first described by the English naturalist Richard Lydekker in 1893 as Lemur menagensis.[2] In 1906, Marcus Ward Lyon, Jr. first described N. bancanus, noting that it was a "well-marked offshoot of N. borneanus, which he also first described in the same publication.[3] By 1953, all of the slow lorises were lumped together into a single species, the Sunda slow loris (Nycticebus coucang).[4] In 1971, that view was updated by distinguishing the pygmy slow loris (N. pygmaeus) as a species, and by further recognizing four subspecies, including N. coucang menagensis, the Bornean slow loris.[5][6] From then until 2005, N. bancanus was considered a synonym of the Bornean slow loris,[7] which was elevated to the species level (as N. menagensis) in 2006, when molecular analysis showed it to be genetically distinct from N. coucang.[8]

A 2013 review of museum specimens and photographs attributed to N. menagensis resulted in elevating two of its former subspecies to the species N. bancanus and N. borneanus.[9] Additionally, N. kayan emerged as a new species, which had previously been overlooked. All newly recognized or elevated species showed significant differences in their "face mask"—the coloration patterns on their face.[9]

Physical description[edit]

Like other slow lorises, it has a vestigial tail, round head, and short ears.[10] It has a rhinarium (the moist, naked surface around the nostrils of the nose) and a broad, flat face with large eyes.[11] Like N. menagensis, this and all other Bornean species lack a second upper incisor, which distinguishes them from other slow lorises.[12] On its front feet, the second digit is smaller than the rest; the big toe on its hind foot opposes the other toes, which enhances its gripping power. Its second toe on the hind foot has a curved grooming claw that it uses for scratching and grooming, while the other nails are straight.[11] It also possesses a specialized arrangement of lower front teeth, called a toothcomb, which is also used for grooming, as with other lemuriform primates.[13] On the ventral side of its elbow, it has a small swelling called the brachial gland, which secretes a pungent, clear oily toxin that the animal uses defensively by wiping it on its toothcomb.[14]

N. bancanus has distinct crimson red fur on its back, the facial markings (facemask) are light in color, and the upper edges of the dark rings around the eyes (circumocular patch) are diffuse, and not rounded or pointed like some of the other slow lorises from Borneo. The circumocular patch does not extend below the zygomatic arch, and the stripe between its eyes is wide. The colored patched on the top of the head is diffused, the band of hair in front of the ears is narrow, and the ears are covered in hair. The body length averages 258.05 mm (10.159 in).[15]

Distribution[edit]

N. bancanus is found in southwestern Borneo, in the Indonesian provinces of West and South Kalimantan, as well as the island of Bangka. On Borneo, its range extends south of the Kapuas River and east towards—but not reaching—the Barito River. The Bangka population is allopatric with the other Bornean species, but the population on Borneo may exhibit some sympatry with N. borneanus in the province of West Kalimantan.[16]

Habitat and ecology[edit]

Like other slow lorises, N. bancanus is arboreal, nocturnal,[10] and omnivorous, eating primarily insects, tree gum, nectar, and fruit.[17] Likewise, this species has a toxic bite, a unique feature found only in slow lorises among primates. The toxin is produced by licking a brachial gland (a gland by their elbow), and the secretion mixes with its saliva to activate. Their toxic bite is a deterrent to predators, and the toxin is also applied to the fur during grooming as a form of protection for their infants. When threatened, slow lorises may also lick their brachial glands and bite their aggressors, delivering the toxin into the wounds. Slow lorises can be reluctant to release their bite, which is likely to maximize the transfer of toxins.[18]

The face mask may help the species identify potential mates by distinguishing species, and may serve as an anti-predator strategy by making its eyes appear larger than they really are.[19]

Conservation[edit]

While this new species has yet to be assessed by the IUCN, N. menagensis was listed as "Vulnerable" as of 2012.[9] Because that species has been divided into four distinct species, each of the new species faces a higher risk of extinction. Accordingly, each of them are expected to be listed as "Vulnerable" at the least, with some of them likely to be assigned to a higher-risk category.[20]

Between 1987 and 2012, one-third of Borneo's forests have been lost, making habitat loss one of the greatest threats to the survival of N. bancanus. The illegal wildlife trade is also a major factor,[9] with loris parts commonly sold in traditional medicine and viral videos on YouTube promoting the exotic pet trade.[20][21][22] However, all slow loris species are protected from commercial trade under Appendix I of CITES.[23]

References[edit]

  1. ^ "Appendices I, II and III" (PDF). Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2010. 
  2. ^ Munds, Nekaris & Ford 2013, p. 46.
  3. ^ Lyon, Jr. 1906, pp. 535–536.
  4. ^ Osman Hill 1953, pp. 156–163.
  5. ^ Groves 1971.
  6. ^ Groves 2001, p. 99.
  7. ^ Groves 2005, p. 122.
  8. ^ Chen et al. 2006, p. 1198.
  9. ^ a b c d Munds, Nekaris & Ford 2013, p. 47.
  10. ^ a b Ankel-Simons 2007, p. 82.
  11. ^ a b Smith & Xie 2008, pp. 159–160.
  12. ^ Munds, Nekaris & Ford 2013, p. 53.
  13. ^ Ankel-Simons 2007, p. 246.
  14. ^ Hagey, Fry & Fitch-Snyder 2007, p. 253.
  15. ^ Munds, Nekaris & Ford 2013, p. 52.
  16. ^ Munds, Nekaris & Ford 2013, p. 52–53.
  17. ^ Nekaris & Bearder 2007, pp. 28–33.
  18. ^ Alterman 1995, pp. 421–423.
  19. ^ Munds, Nekaris & Ford 2013, p. 49.
  20. ^ a b Wall, T. (13 December 2012). "Three new species of venomous primate identified by MU researcher". Missouri University News Bureau. Archived from the original on 24 December 2012. Retrieved 19 December 2012. 
  21. ^ Bryner, J. (14 December 2012). "Slow loris species, Nycticebus kayan, discovered in Borneo". The Huffington Post. Archived from the original on 4 January 2013. Retrieved 15 December 2012. 
  22. ^ Walker, M. (13 December 2012). "Primate species: new slow loris found in Borneo". BBC News. Archived from the original on 24 December 2012. 
  23. ^ Nekaris & Munds 2010, p. 390.

Literature cited[edit]

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Bornean slow loris

The Bornean slow loris (Nycticebus menagensis) or Philippine slow loris is a strepsirrhine primate and a species of slow loris that is native to the north and east coastal areas of the island of Borneo, as well as the Sulu Archipelago in the Philippines. The species was first named in 1892, but lumped into the widespread Sunda slow loris (N. coucang) in 1952. However, it was promoted to full species status based on molecular analysis in 2006. In 2013, two former subspecies of the Bornean slow loris were elevated to species status, and a new species—N. kayan—was recognized among the Bornean population.

Weighing 265–300 grams (9.3–11 oz), it is one of the smallest of the slow lorises, and can be distinguished from other slow lorises by its pale golden to red fur, the lack of markings on its head, and consistent absence of a second upper incisor. Like other slow lorises, it has a vestigial tail, round head, short ears, a curved grooming claw for grooming, and a gland that produces an oily toxin that the animal uses for defense. The Bornean slow loris is arboreal, nocturnal, and occurs in low densities, making it difficult to locate. It is also the least studied of Indonesia's slow lorises. It is found at elevations between 35–100 meters (115–330 ft) in primary and secondary lowland forest, gardens, and plantations. Information about its diet is limited, but it is suspected to be one of the more insectivorous slow loris species, and is also known to eat gum from woody plants.

The Bornean slow loris was classified as "Vulnerable" by the International Union for Conservation of Nature (IUCN) in 2008, is included in CITES Appendix I, which prevents international commercial trade, and is protected by Indonesian law. Prior to being divided into four distinct species in 2013, it was found in numerous protected areas within its range, making it the least threatened of the slow lorises. However, since the taxonomic split, it may face a higher risk of extinction. It is sparsely distributed throughout its range and is threatened by illegal wildlife trade, including the exotic pet trade, and habitat loss.

Contents

Taxonomy and phylogeny[edit]

The Bornean slow loris was first described based on specimens collected by Frank S. Bourns and Dean C. Worcester during the Menage Scientific Expedition to the Philippines and Borneo in the early 1890s. The original collection was made between 5 October and 5 November 1891 near Tataan, Tawi-Tawi Island, in the Philippines,[4] however this type specimen is missing as of 2013.[5] The specimens were given to Henry F. Nachtrieb, President of the Minnesota Academy of Sciences and Chairman of the Zoology Department at the University of Minnesota. Nachtrieb was the first to use the name menagensis in 1892, based on a description of the species sent to him by Worcester in 1891.[6] Worcester's progress report included a description of the specimen and an explanation on how they had obtained it:

I now come to the curious mammal of which I enclose description. Shortly before we left for Tawi Tawi the Jesuit priest here, Padre Marche, informed us that just before our arrival he had made a trip to Tawi Tawi, and had bought of the Moros there a curious animal. He said it has the face of a bear, the hands of a monkey, moved like a sloth, and was called "cocam" by the natives ... I believe nothing of this kind has been found in the Philippines before, and it makes an important addition to the rather meager list of Philippine mammals. It is evidently one of the Lemuridae, but as generic characteristics are not given in the book I have, I cannot go farther.
—Dean C. Worcester[7]

Nachtrieb did not assign the name to a specific genus, noting that it was "an undescribed member of the Lemuridae".[8] The following year, the English naturalist Richard Lydekker published the combination Lemur menagensis in The Zoological Record.[9] This makes Lydekker the authority of the species name menagensis, because he was the first to use the specific name in combination with the name of a genus, although some subsequent authors credited other workers.[10]

In his influential 1953 book Primates: Comparative Anatomy and Taxonomy, the primatologist William Charles Osman Hill placed all the slow lorises in one species, N. coucang.[11] In 1971, however, Colin Groves recognized the pygmy slow loris (N. pygmaeus) as a separate species, and divided N. coucang into four subspecies, including Nycticebus coucang menagensis.[12][13] The Bornean slow loris was elevated to the species level (as Nycticebus menagensis) in 2006 when molecular analysis of DNA sequences of the D-loop and the cytochrome b gene demonstrated it to be genetically distinct from N. coucang.[14] The genetic evidence was corroborated by both a previous study (1998) on morphology (based on craniodental measurements) that indicated distinct differences between the subspecies that were consistent with separation at the species level,[15] and a later study (2010) of facial markings.[16]

Early in its own taxonomic history, distinguishing coloration patterns and size differences resulted in the division of the Bornean slow loris into four subspecies: N. m. bancanus, N. m. borneanus, N. m. menagensis, and N. m. philippinus.[17] These later became taxonomic synonyms, although in 2013 N. bancanus and N. borneanus were elevated to species status based on unique facial markings. Furthermore, a new species—N. kayan—was also identified within the Bornean population.[18][19] The southern Philippine slow lorises (N. m. philippinus or N. philippinus) identified by Spanish zoologist Ángel Cabrera in 1908[20] remains a synonym since the 2013 study was unable to find its type specimen and found no distinguishable characteristics between the Philippine and northern Bornean populations. Additionally, the syntype for N. menagensis was collected by Lydekker in 1893 from the Philippine island of Tawi-Tawi, and Lydekker's species name has precedence under the Principle of Priority.[21]

Physical description[edit]

Like other slow lorises, the tail of the Bornean slow loris is vestigial and it has a round head and short ears.[22] It has a rhinarium (the moist, naked surface around the nostrils of the nose) and a broad, flat face with large eyes. On its front feet, the second digit is smaller than the rest; the big toe on its hind foot opposes the other toes, which enhances its gripping power. Its second toe on the hind foot has a curved grooming claw that the animal uses for scratching and grooming, while the other nails are straight.[23] It also possesses a specialized arrangement of lower front teeth, called a toothcomb, which is also used for grooming, as with other lemuriform primates.[24] It also has a small swelling on the ventral side of its elbow called the brachial gland, which secretes a pungent, clear oily toxin that the animal uses defensively by wiping it on its toothcomb.[25]

The body weight of for the species is typically in the range of 265–300 grams (9.3–11 oz),[26] although weights of up to 700 grams (25 oz) have been recorded.[27] One of the smallest of the slow lorises, it can be distinguished from the other species by its pale golden to red fur, light marks on its head, and the consistent lack of a second upper incisor.[15][28] The body length averages 274.2 mm (10.80 in).[29] Its skull length ranges between 54.5 and 56.5 mm (2.15 and 2.22 in),[30] roughly intermediate in size between the smaller pygmy slow loris and the larger Sunda slow loris.[31] The Bornean slow loris always has patches encircling the eye that end just below it. In contrast, the Sunda slow loris is characterized by medium width hair anterior to the opening of the ear, and the Javan slow loris always has a diamond stripe between the eyes.[16] In comparison to the other three species of slow lorises on Borneo, the N. menagensis has very light colored and contrasting facial markings. The rings around the eyes are either rounded or diffused-edged on top, while the bottom occasionally extends down below the zygomatic arch. The stripe between its eyes is narrow, the ears usually lack fur, the patch on the top of the head is mostly diffused, and the band of fur in front of the ears varies in width.[29]

Distribution[edit]

Following the taxonomic split in 2013 of the four species of slow loris in Borneo, N. menagensis is now restricted to the north and east coastal areas in the provinces of Brunei, Sabah, and East Kalimantan. It is also found on the southern Philippine Islands, known as the Sulu Archipelago,[29] and may be found on other nearby islands, such as the Banggi Island off Sabah.[32] In the Sulu Archipelago, it occurs in the Tawi-Tawi Group, in the west of the archipelago, including the islands of Tawi-Tawi, Bongao, Sanga-Sanga, Simunul, and possibly other small islands. It does not occur on the island of Jolo, further to the east, and although it has been recorded from Mindanao—a large island in the southern Philippines—the record was in error.[33] The species may be extinct on some Philippine islands, but is likely to persist on the smaller islands.[1] Because the species is so popular as a pet, zoologists Guy Musser and Lawrence Heaney suggested in 1985 that the Philippine populations may have been introduced there by humans.[34]

It is considered to be sympatric with N. kayan.[29] Fossils of this species have been found in the Late Pleistocene site of Niah in Sarawak.[35]

Habitat and ecology[edit]

The Bornean slow loris is the least studied of Indonesia's slow lorises.[36] In a field study at the Sabangau National Park in Central Kalimantan, only 12 slow loris sightings were made over a 75-day period.[37] All were seen in the trees at heights of 15–20 m (49–66 ft). They were encountered singly, as mother and offspring, or in adult trios. Of the two trios, both were on fruiting trees, Calophyllum hosei and Syzygium cf. nigricans. In another survey conducted at Wehea Forest, East Kalimantan, only one Bornean slow loris—seen at a height of 30 m (98 ft)—was encountered in an area of more than 30 km2.[1] Other surveys confirm that the animal is difficult to locate, and occurs in low densities.[38][39][40]

The species occurs in primary and secondary lowland forest, gardens, and plantations, at elevations between 35–100 m (115–330 ft). Interviews conducted with Philippines locals indicate that it is commonly seen in citrus trees (calamansi), and may be tolerant of a variety of habitats. It is nocturnal, and almost entirely arboreal.[1] Although data on diet is limited, based on cranial size and morphology, the Bornean slow loris is suspected to be one of the more insectivorous slow loris species.[41] It has also been observed feeding on the gum from an unidentified liana (a long-stemmed woody vine).[27]

Conservation[edit]

In a 2005 report on the effect of logging on wildlife conservation in Indonesia, the authors claimed the Bornean slow loris to be "common" throughout Borneo.[42] However, as pointed out by Nekaris and colleagues, this assessment was based on field research data and historic museum specimens, and cannot be considered reliable, as "loris ‘presence’ is usually not determined first-hand, and it also cannot be presumed that lorises still occur in areas from where they were once collected."[43] The species appears to be uncommon throughout its range, including a very limited distribution in the Philippines. Surveys have demonstrated that, compared to other slow loris species, the Bornean slow loris is rare, and sparsely distributed throughout its range.[44]

The Bornean slow loris is listed in CITES Appendix I, which prevents international commercial trade; it is also protected by Indonesian law. The species is often confused with other slow lorises in animal rescue centers, as it is not well-covered in field guides. The species occurs in a number of protected areas throughout its range, including some fragmented forests.[1] Threats to the species include the illegal local exotic pet trade[40][45] and habitat loss due to burning and conversion to palm oil plantations. Additionally, uncontrolled release of pets in some areas is also a threat to the species.[1]

Prior to being split into four species in 2013, the Bornean slow loris was among the least threatened of the slow lorises,[1] and its situation was considered to be good due to its presence in a high percentage of "low risk" areas on Borneo.[46] It was classified as "Vulnerable" by the IUCN, who consider there to have been a greater than 30% reduction in population between roughly 1984 and 2008, based on harvesting for the pet trade and extensive habitat loss.[1] Because that species has been divided into four distinct species since the 2008 IUCN assessment, each of the new species faces a higher risk of extinction. Accordingly, each of them are expected to be listed as "Vulnerable" at the least, with some of them likely to be assigned to a higher-risk category.[47]

References[edit]

  1. ^ a b c d e f g h Nekaris, A. & Streicher, U. (2008). "Nycticebus menagensis". IUCN Red List of Threatened Species. Version 2010.4. International Union for Conservation of Nature. Retrieved 23 January 2011. 
  2. ^ "Appendices I, II and III" (PDF). Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2010. 
  3. ^ Nekaris & Jaffe 2007, p. 188.
  4. ^ Timm & Birney 1992, p. 679.
  5. ^ Munds, Nekaris & Ford 2013, pp. 51 & 53.
  6. ^ Timm & Birney 1980, p. 680.
  7. ^ Worcester & Bourns 1905, p. 149.
  8. ^ Nachtrieb 1892.
  9. ^ Lydekker 1893, pp. 24–25.
  10. ^ Timm & Birney 1992, p. 682.
  11. ^ Osman Hill 1953, pp. 156–163.
  12. ^ Groves 1971.
  13. ^ Groves 2001, p. 99.
  14. ^ Chen et al. 2006, p. 1198.
  15. ^ a b Ravosa 1998.
  16. ^ a b Nekaris & Munds 2010.
  17. ^ Munds, Nekaris & Ford 2013, p. 47.
  18. ^ Munds, Nekaris & Ford 2013, p. 46.
  19. ^ Walker, M. (13 December 2012). "Primate species: new slow loris found in Borneo". BBC News. Archived from the original on 24 December 2012. 
  20. ^ Cabrera 1908, pp. 136–137.
  21. ^ Munds, Nekaris & Ford 2013, p. 49.
  22. ^ Management Authority of Cambodia (3–15 June 2007). "Notification to Parties: Consideration of Proposals for Amendment of Appendices I and II" (PDF). Netherlands: CITES. p. 31. Archived from the original on 8 January 2011. Retrieved 9 January 2011. 
  23. ^ Smith & Xie 2008, pp. 159–160.
  24. ^ Ankel-Simons 2007, p. 246.
  25. ^ Hagey, Fry & Fitch-Snyder 2007, p. 253.
  26. ^ Nekaris, Blackham & Nijman 2008, p. 734.
  27. ^ a b Nekaris et al. 2010, p. 157.
  28. ^ Chen et al. 2006.
  29. ^ a b c d Munds, Nekaris & Ford 2013, p. 53.
  30. ^ Groves 2001, p. 98.
  31. ^ Groves 1998, p. 24.
  32. ^ Nor 1996, p. 28.
  33. ^ Fooden 1991, p. 287.
  34. ^ Musser & Heaney 1985, p. 30.
  35. ^ Tougard 2001.
  36. ^ Nekaris & Munds 2010, p. 21.
  37. ^ Nekaris, Blackham & Nijman 2008, p. 737.
  38. ^ Wells et al. 2004.
  39. ^ Duckworth 1997.
  40. ^ a b Munds et al. 2008.
  41. ^ Ravosa 1998, p. 239.
  42. ^ Meijaard et al. 2005, p. 242.
  43. ^ Nekaris, Blackham & Nijman 2008, p. 735.
  44. ^ Nekaris, Blackham & Nijman 2008, p. 744.
  45. ^ Braun, D. (2010). "Love potions threaten survival of lorises". National Geographic. Archived from the original on 9 January 2011. Retrieved 9 January 2011. 
  46. ^ Thorn et al. 2009, p. 295.
  47. ^ Wall, T. (13 December 2012). "Three new species of venomous primate identified by MU researcher". Missouri University News Bureau. Archived from the original on 24 December 2012. Retrieved 19 December 2012. 

Literature cited[edit]

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