Tapanuli orangutan

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Tapanuli orangutan
Adult male
Adult female
Both near Lake Toba

Critically Endangered  (IUCN 3.1)[1]
CITES Appendix I (CITES)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Suborder: Haplorhini
Infraorder: Simiiformes
Family: Hominidae
Genus: Pongo
Species:
P. tapanuliensis
Binomial name
Pongo tapanuliensis
Nurcahyo, Meijaard, Nowak, Fredriksson & Groves, 2017[note 1]
Tapanuli orangutan is located in Sumatra
Tapanuli orangutan
Approximate location in Sumatra

The Tapanuli orangutan (Pongo tapanuliensis) is a

critically endangered species list.[5]

Taxonomy

Discovery and naming

An isolated

Zoological Museum of Bogor.[3] The skull and teeth of the Batang Toru male differ significantly from those of the other two orangutan species.[3][10] Comparisons of the genomes of all 37 orangutans using principal component analysis and population genetic models also indicated that the Batang Toru population is a separate species.[3]

The specific name, tapanuliensis, as well as the common name, Tapanuli orangutan, refer to Tapanuli, the hilly region in North Sumatra where the species lives.[3][11]

Phylogeny

Genetic comparisons show that Tapanuli orangutans diverged from Sumatran orangutans about 3.4 million years ago, and became more isolated after the Lake Toba eruption that occurred about 75,000 years ago.[3][4][9] They had continued sporadic contact that stopped between 10,000 and 20,000 years ago. Tapanuli orangutans diverged from Bornean orangutans about 674,000 years ago.[10] Orangutans were able to travel from Sumatra to Borneo because the islands were connected by land bridges as parts of Sundaland during recent glacial periods when sea levels were much lower.[9] The present range of Tapanuli orangutans is thought to be close to the area where ancestral orangutans first entered what is now Indonesia from mainland Asia.[3]

Description

Males of each orangutan species (from left to right): Bornean, Sumatran, Tapanuli

Tapanuli orangutans resemble Sumatran orangutans more than Bornean orangutans in body build and fur color.[3] However, they have frizzier hair, smaller heads, and flatter and wide faces.[4] Dominant male Tapanuli orangutans have prominent moustaches and large flat cheek pads, known as flanges, covered in downy hair. The Tapanuli orangutan differs from the other two existing orangutan species in several specific features:

  • their upper canines are larger;
  • they have a shallower face depth;
  • their
    pharyngotympanic tube
    is shorter;
  • they have a shorter mandibular joint;
  • they have a narrower maxillary incisor row;
  • the distance across the palate at the first molars are narrower;
  • there is a smaller horizontal length between the mandibular symphysis;
  • they have a smaller inferior torus; and
  • the width of the ascending ramus located in the mandible.

As with other two orangutan species, males are larger than females; males are 137 cm (54 in) in height and 70–90 kg (150–200 lb) in weight, females are 110 cm (43 in) in height and 40–50 kg (88–110 lb) in weight.[12] When comparing the Tapanuli orangutan with the Pongo abelii, the Tapanuli orangutan has a deeper suborbital fossa, a triangular pyriform aperture, and a facial profile that is more angled.[3]

Behavior

The loud, long-distance call or 'long call' of male Tapanuli orangutans has a higher maximum

Sumatran dholes and crocodiles.[14] Tapanuli orangutans have slow reproductive rates causing a problem in increasing population.[15]

Habitat and distribution

Tapanuli orangutans live in tropical and subtropical moist broadleaf forests located south of Lake Toba in Sumatra. The entirety of the species is found in an area of about 1,000 km2 (390 sq mi) at elevations from 300 to 1,300 m (980 to 4,300 ft).[3] Tapanuli orangutans are separated from the island's other species of orangutan, the Sumatran orangutan, by just 100 km (62 mi).[11]

Conservation

With fewer than 800 individuals restricted to an area of about 1,000 km2 (390 sq mi), the Tapanuli orangutan is the second rarest great ape.

critically endangered by the International Union for Conservation of Nature (IUCN) because of hunting, conflict with humans, the illegal wildlife trade, rampant habitat destruction for small scale agriculture, mining and a proposed hydroelectric dam, the Batang Toru hydropower project, in the area with the highest density of orangutans, which could impact up to 10% of its already dwindling habitat and degrade important wildlife corridors.[1][3][13] Conservationists predict an 83% decline in three generations (75 years) if the necessary conservation measures and practices are not implemented.[1] Inbreeding depression is likely due to the small population size and fragmented range. This is supported by the genomes of the two Tapanuli orangutan individuals, which show signs of inbreeding.[3] In August 2019 Swiss environmental group PanEco, which is a partner in the Sumatran Orangutan Conservation Programme, dropped its previous opposition to the dam, several months after firing several researchers who opposed the new strategy.[16]

Notes

  1. ^ The description of the Tapanuli orangutan was a collaboration between 37 scientists from institutions around the world but its binomial name (scientific name) was provided by the five scientists cited here.

References

  1. ^
    doi:10.2305/IUCN.UK.2017-3.RLTS.T120588639A120588662.en
    . Retrieved 19 November 2021.
  2. ^ "Appendices | CITES". cites.org. Retrieved 2023-03-01.
  3. ^
    PMID 29103940
    .
  4. ^
    PMID 29120449
    .
  5. PMID 30112142
    .
  6. ^ Natuur in Zuid- en Oost- Borneo. Fauna, flora en natuurbescherming in de Zuider- en Ooster-Afdeeling van Borneo. In 3 Jaren Indisch Natuur Leven: Opstellen over Landschappen, Dieren en Planten, Tevens Elfde Verslag (1936-1938) [Nature in South and East Borneo. Fauna, flora and nature conservation in the southern and eastern part of Borneo. In 3 Years Dutch Indies Nature Life: Compilation on Landscapes, Animals and Plants, Eleven Reports (1936-1938)] (in Dutch). Batavia, Indonesia: Nederlandsch-Indische Vereeniging tot Natuurbescherming. 1939. pp. 334–411.
  7. ^ Meijaard, Erik (25 December 2015). "A Sumatran wonderland". Jakarta Globe. Archived from the original on 10 August 2018. Retrieved 15 November 2017.
  8. ^ Gill, Victoria (2 November 2017). "New great ape species identified". BBC News. Retrieved 3 November 2017.
  9. ^ a b c d Goldman, Jason G. (2 November 2017). "New species of orangutan is rarest great ape on earth". National Geographic Society. Archived from the original on November 2, 2017. Retrieved 6 November 2017.
  10. ^ a b c Stokstad, Erik (12 November 2017). "New great ape species found, sparking fears for its survival". Science. Retrieved 15 November 2017.
  11. ^ a b Davis, Nicola (2 November 2017). "New species of orangutan discovered in Sumatra – and is already endangered". The Guardian. Retrieved 15 November 2017.
  12. ^ "Tapanuli Orangutan". New England Primate Conservancy. Retrieved 2020-11-06.
  13. ^ a b Leahy, Stephen (9 August 2018). "Hydroelectric Dam Threatens to Wipe Out World's Rarest Ape". National Geographic Society. Archived from the original on 10 August 2018.
  14. ^ "Tapanuli Orangutan Facts, Pictures & Information For Kids & Adults". Active Wild. Retrieved 2020-11-06.
  15. S2CID 155174152
    .
  16. S2CID 202568749
    .

External links
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