Wikipedia

Javan slow loris

TheJavan slow loris(Nycticebus javanicus) is astrepsirrhineprimateand aspeciesofslow lorisnative to the western and central portions of the island ofJava,inIndonesia.Although originally described as a separate species, it was considered asubspeciesof theSunda slow loris(N. coucang) for many years, until reassessments of itsmorphologyand genetics in the 2000s resulted in its promotion to full species status. It is most closely related to the Sunda slow loris and theBengal slow loris(N. bengalensis). The species has two forms, based on hair length and, to a lesser extent, coloration.

Javan slow loris
CITESAppendix I(CITES)[2]
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Strepsirrhini
Family: Lorisidae
Genus: Nycticebus
Species:
N. javanicus
Binomial name
Nycticebus javanicus
Range of the Javan slow loris
Synonyms[4]

Its forehead has a prominent white diamond pattern, which consists of a distinct stripe that runs over its head and forks towards the eyes and ears. The Javan slow loris weighs between 565 and 687 g (1.25 and 1.51 lb) and has a head-body length of about 293 mm (11.5 in). Like all lorises, it isarborealand moves slowly across vines andlianasinstead of jumping from tree to tree. Its habitat includesprimaryandsecondary forests,but it can also be found in bamboo andmangroveforests, and on chocolate plantations. Its diet typically consists of fruit, treegum,lizards, and eggs. It sleeps on exposed branches, sometimes in groups, and is usually seen alone or in pairs.

The Javan slow loris population is in sharp decline because ofpoachingfor theexotic pettrade, and sometimes fortraditional medicine.Remaining populations have lowdensities,andhabitat lossis a major threat. For these reasons, theInternational Union for Conservation of Nature(IUCN) lists its status ascritically endangered,and it has also been included on the 2008–2010 list of "The World's 25 Most Endangered Primates".It is protected by Indonesian law and, since June 2007, is listed underCITES Appendix I.Despite these protections, as well as its presence in severalprotected areas,poaching continues; the wildlife protection laws are rarely enforced at the local level.

Taxonomy and phylogeny

edit

The Javan slow loris (Nycticebus javanicus) was firstdescribedscientifically in 1812, by the French naturalistÉtienne Geoffroy Saint-Hilaire.[5]Thespecies namejavanicusrefers to its place of origin. However, the species was not recognized for long; by 1840,René Primevère Lessonclassified it as one of several varieties of a single species of slow loris, which he calledBradylemur tardigradus.[6]In 1921,Oldfield Thomasnamed a second species of slow loris from Java,Nycticebus ornatus.[7]

In his 1971 review of slow loris taxonomy, taxonomist and primatologistColin Grovesrecognized the Javan slow loris as asubspecies,Nycticebus coucang javanicus,of theSunda slow loris(N. coucang), withornatusas asynonym.[8]It was first recognized as a distinct species again in a 2000 Indonesianfield guideon primates by Jatna Supriatna and Edy Hendras Wahyono.[9]In 2008, Groves and Ibnu Maryanto promoted it to species status, based on an analysis of cranialmorphologyand characteristics ofpelage.[10]Molecular analysisofDNA sequencesof theD-loopandcytochromebgenes demonstrated it to be genetically distinct from other slow loris species;phylogenetically,it is sister to acladecontaining theBengal slow loris(N. bengalensis) and the Sunda slow loris.[11]Due to its close resemblance to neighboring slow loris species, even rescue centers have been known to misidentify it.[1]

There are two forms of the Javan slow loris, distinguished mainly by differences in hair length. These have occasionally been recognized as separate species,N. javanicusandN. ornatus,but are currently both classified as a single species, although their exact taxonomic status remains unclear.[1][12][13]

Anatomy and physiology

edit
The Javan slow loris has a distinct stripe that runs the length of its back and forks at the crown, leading to the eyes and ears.

The Javan slow loris weighs between 565 and 687 g (1.25 and 1.51 lb)[14]and is similar in appearance to the largest slow loris, the Bengal slow loris. Its face and back are marked with a distinct stripe that runs over the crown and forks, leading to the eyes and ears, which leaves a white diamond pattern on the forehead.[15]Its color is yellowish-gray. In contrast, its head, neck, and shoulders havecreamhues. Like theBornean slow loris(N. menagensis), it lacks the secondincisor(I2) in itsdentition.[16]

The Javan slow loris is larger than both of the other Indonesian slow lorises, the Sunda slow loris and the Bornean slow loris.[16]Based on averages determined from six specimens obtained from the illegal wildlife trade in Java, othermorphometricparameters are as follows: head length, 59.2 mm;muzzlelength, 19.9 mm; head breadth, 43.6 mm; body breadth, 250.8 mm; head and body length, 293.1 mm; chest girth, 190.8 mm; dark percentage girth (girth measurement of zone with dark dorsal hair, measured as a percent of girth circumference), 48.0 mm; neck circumference, 136.7 mm; tail length, 20.4 mm;humeruslength, 67.2 mm;radiuslength, 71.8 mm;femurlength, 83.2 mm;tibialength, 85.9 mm; hand span, 59.1 mm; foot span, 70.3 mm; and ear length, 16.8 mm.[17]

Theornatusmorphotype is most reliably distinguished by its longer fur, averaging 26.8 mm compared to 22.4 mm injavanicus.[18]Other distinguishing characteristics include overall color (generally light brown inornatuscompared with brown to reddish injavanicus), and amount of brown coloring in the fur (ornatushas less brown thanjavanicus,resulting in a lighter-colored ventral region).[19]

In the 1860s, thebrainof the Javan slow loris was examined byWilliam Henry Flower,acomparative anatomistwho specialized in the primate brain. In addition to detailing the organization, shape, and measurements of its brain, he noted that the form and surface markings were comparable to that oflemurs.He argued against grouping strepsirrhines withInsectivora(a now-abandoned biological grouping) and noted that the brain had features transitional between other primates and "inferior" mammals such asbatsandcarnivorans.[20]

Behavior and ecology

edit

Like otherlorises,the Javan slow loris isnocturnaland arboreal, relying on vines andlianas.[1]However, the animal has been observed moving on the ground to cross open spaces in disturbed habitat.[21]It moves through thecanopyat heights between 3 and 22 m (10 and 72 ft) and is often encountered at heights between 1.5 and 9.5 m (5 and 31 ft).[1]

The Javan slow loris will eat fruit, lizards, eggs, and chocolate seeds.[21]It is also known to eat thegumof trees of the genusAlbizia,in thelegumefamily,Fabaceae,as well as from the palm genusArenga(familyArecaceae).[22]Javan slow lorises are seen alone or in pairs and are sometimes found sleeping in groups. Instead of sleeping in nest holes, they sleep curled up on branches.[21]Like other slow lorises, the Javan slow loris has a distinctive call that resembles a high-frequency whistle.[23]The species is a host for the parasiticflatworm,Phaneropsolus oviforme.[24]

Distribution

edit

The species is found only on the western and central portion of the island of Java inIndonesia.[1]Its presence has been confirmed in theDieng Mountains,and it is known to be found in low densities atGunung Gede Pangrango National Park(inmontanecloud forests) andMount Halimun Salak National Park,often only where human disturbance is minimal.[21]It inhabits both primary and secondary disturbed forest, and can be found from sea level to 1,600 m (5,200 ft), although it is more commonly found at higher elevations since lower elevations tend to be deforested.[1]A study in 2000 showed that in addition to primary and secondary forest, the Javan slow loris could be found in bamboo forests,mangroveforests, and on plantations—particularly chocolate plantations. In 2008, they were observed in West Java to occupy mixed-crop home gardens, tolerating high levels of human disturbance.[21]

Conservation

edit
See also:Conservation of slow lorises
The Javan slow loris is commonly sold as a pet in the markets of Indonesia, despite local laws and CITES Appendix I protection.

The Javan slow loris is listed by theInternational Union for Conservation of Nature(IUCN) as "critically endangered,"primarily due to a rapid decline in population. For the 21–24 years prior to its 2008 assessment by the IUCN—which corresponds to three generations for the species—its numbers had dropped by at least 50%.[1]Population data for the species is sparse,[25]but a few studies have shown a lowpopulation densityof 0.20 to 0.02 individuals per km2.[1]

Its numbers are still decreasing, primarily because ofpoaching.In Indonesia, it is sometimes used intraditional medicine,because of myths of it having magical and curative properties, but it is more frequently sold as anexotic pet.[1][26]The species is easily captured because of its slow movement, nocturnal habits, and its tendency to sleep on exposed branches. They are both actively sought for the pet trade and collected opportunistically when felling forests. Its habitat is also in decline, although most of thehabitat lossoccurred by the mid-1980s.[1]Within its range, human land use is intense.[27]Environmental niche modellingindicates that the Javan slow loris is more threatened by habitat loss than other slow loris species.[25]For these reasons, the Javan slow loris has been included on "The World's 25 Most Endangered Primates"published by theIUCN Species Survival Commission Primate Specialist Group(IUCN/SSC PSG), theInternational Primatological Society(IPS), andConservation International(CI).[28]

Along with all other slow lorises, the Javan slow loris was elevated fromCITES Appendix IItoCITES Appendix Iin June 2007, offering it increased protection from commercial trade.[29]It is also protected by Indonesian law, but according to loris researchers Nekaris and Jaffe, "effective law enforcement with respect to wildlife protection laws is all but non-existent in Indonesia".[17]The species can be found in severalprotected areas,but its numbers are uncertain. Captive collections of the Javan slow loris can be found inPrague,Czech Republic,Jakarta,Indonesia, andSingapore.[1]

On Java conservationist working for theLittle Fireface Projecthave built a network of mid-air walkways to enable Javan slow loris to move between treetops in areas where land has been cleared for farming. These walkways also serve as irrigation pipes which have helped local farmers who in turn assist with the maintenance of the walkways.[30]

References

edit
  1. ^abcdefghijklNekaris, K.A.I.; Shekelle, M; Wirdateti; Rode-Margono, E.J.; Nijman, V. (2021) [errata version of 2020 assessment]."Nycticebus javanicus".IUCN Red List of Threatened Species.2020:e.T39761A205911512.doi:10.2305/IUCN.UK.2020-2.RLTS.T39761A205911512.en.
  2. ^"Appendices I, II and III"(PDF).Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 2010. Archived fromthe original(PDF)on 2010-12-24.
  3. ^Thomas 1921,p. 627.
  4. ^Groves 2005,p. 122.
  5. ^Saint-Hilaire 1812,p. 164.
  6. ^Lesson 1840,pp. 240–243.
  7. ^Thomas 1921,p. 527.
  8. ^Groves 1971,pp. 49–51.
  9. ^Supriatna & Wahyono 2000,pp. 19–24.
  10. ^Groves & Maryanto 2008,p. 120.
  11. ^Chen et al. 2006,pp. 1197–1198.
  12. ^Nekaris & Jaffe 2007,p. 192.
  13. ^Thomas 1921,p. 628.
  14. ^Nekaris, Blackham & Nijman 2008,p. 734.
  15. ^Nekaris et al. 2009,p. 44.
  16. ^abGroves 1971,p. 49.
  17. ^abNekaris & Jaffe 2007,p. 191.
  18. ^Nekaris & Jaffe 2007,p. 188.
  19. ^Nekaris & Jaffe 2007,p. 193.
  20. ^Gray 1862,pp. 103–105.
  21. ^abcdeNekaris & Munds 2010,p. 388.
  22. ^Nekaris et al. 2010,p. 157.
  23. ^Nekaris, Blackham & Nijman 2008,p. 743.
  24. ^Dawes 2011,p. 384.
  25. ^abNekaris & Munds 2010,pp. 383–384.
  26. ^Nekaris et al. 2010,p. 877.
  27. ^Thorn et al. 2009,p. 295.
  28. ^Nekaris et al. 2009,pp. 44–46.
  29. ^McGreal 2007,p. 15.
  30. ^"The mid-air walkways saving endangered animals".BBC News.Retrieved2021-05-16.

Literature cited

edit
edit

Retrieved from "https://en.wikipedia.org/w/index.php?title=Javan_slow_loris&oldid=1232378955"