Tapanuli orangutan

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Tapanuli orangutan
Tapanuli orangutan (Pongo tapanuliensis)

Tapanuli orangutan ( Pongo tapanuliensis )

Systematics
without rank: Old World Monkey (Catarrhini)
Superfamily : Human (Hominoidea)
Family : Apes (Hominidae)
Subfamily : Ponginae
Genre : Orangutans ( pongo )
Type : Tapanuli orangutan
Scientific name
Pongo tapanuliensis
Nurcahyo , Meijaard , Nowak , Fredriksson & Groves , 2017

The Tapanuli Orangutan ( Pongo tapanuliensis ) is a great ape . Together with the Sumatran orangutan and the Bornean orangutan , it forms the genus of orangutans . Phenotypically, it differs from the other Sumatran orangutans mainly through its head shape. The species lives in a narrowly limited range that includes a forest area south of Lake Toba on the island of Sumatra . Originally the population there was assigned to the Sumatran orangutan, but a study from 2017 gave it its own species status.

features

Female Tapanuli orangutan

The Tapanuli orangutan resembles the Sumatran orangutan ( Pongo abelii ) more closely than the Bornean orangutan ( Pongo pygmaeus ) in its body shape and cinnamon brown fur . The hair, however, is more frizzy than the very loose hair of the Sumatran orangutan. Dominant males have a showy beard and flat cheekbones covered with downy hair. In older males, the cheek bulges are more similar to those of the Bornean orangutan. In contrast to the latter, females of the Tapanuli orangutan also have beards.

Further differences can be found primarily in the features of the skull. The skull is generally smaller than that of the other orangutans. It stands out due to its lower height of the rostrum . Furthermore, the upper canine is wider, the upper row of incisors is narrower and the palate is narrower at the level of the first molar . On the lower jaw, both the symphysis and the ascending branch are made shorter. Compared to the Sumatran orangutan, the eye windows are narrower, the occipital opening is smaller and the lower incisors are narrower. In addition to the anatomical features, there are also deviations in behavior. The males' calls reach a higher frequency with 800 Hz than with the Sumatran orangutan and with more than 111 seconds a longer duration than with the Bornean orangutan.

distribution

Distribution area of ​​the Tapanuli orangutan

The Tapanuli orangutan is endemic to the northern part of the island of Sumatra, which belongs to Indonesia . There he comes in Batang Toru forest on the border of the administrative districts Tapanuli Seletan , Tapanuli Tengah and Tapanuli Utara in the province of North Sumatra before. The Batang Toru Forest forms a closed forest area that is only cut up by the Batang Toru River and a side valley. It extends over altitudes of 150 to 1800 m, in some cases very steep slopes prevail. The dominant plant families are the sapote family , myrtle family and laurel family. The entire range of the Tapanuli orangutan in the forest area is estimated to be around 1000 km². The animals are restricted to low to medium-high mountain locations from 300 to 1300 m above sea level. The population may not include more than 800 individuals, an estimate from 2012 comes to a total of 550 animals with a density of 0.23 individuals per square kilometer. The highest density of individuals is achieved in primary rainforests , but animals also occur at the edges of forests and in forests mixed with agricultural areas. Originally the species probably also occurred further south and west, but observations are more anecdotal in nature. The southern limit of distribution of the Sumatran orangutan is about 100 km further north.

Way of life

In comparison to the Sumatran orangutan, the Tapanuli orangutan occurs in higher mountain areas on average with cooler mean annual temperatures and lower annual rainfall. It lives in forests that grow on young igneous rocks. In these it feeds on a number of plants that have not yet been found in other orangutan populations. These include Agathis borneensis from the Araucaria family , Gymnostoma sumatranum from the Casuarina family and various stone slices such as Dacrycarpus imbricatus , Dacrydium beccarii and Podocarpus neriifolius . The plants mentioned were consumed by the animals in around 22% of all observations. As a result, the diet of the Tapanuli orangutan is very different from that of its relatives.

Systematics

Internal systematics of the orangutans according to Nater et al. 2017
 Pongo  

 Pongo abelii


   

 Pongo tapanuliensis


   

 Pongo pygmaeus




Template: Klade / Maintenance / Style

The Tapanuli orangutan is a kind from the genus of orangutan ( Pongo ) in the family of apes (Hominidae). The genus also contains the Sumatran orangutan ( Pongo abelii ) and the Bornean orangutan ( Pongo pygmaeus ). According to genetic analyzes, the orangutans on Sumatra separated into two groups as early as the Pliocene , about 3.38 million years ago: a northern, which led to the Sumatran orangutan, and a southern. It is therefore assumed that the northern group on Lake Toba form the most pristine orangutans in their tribal history. There was still a low gene flow between the two groups, estimated at 0.3 to 0.9 individuals per generation. The gene flow then largely collapsed at the beginning of the New Pleistocene , which the researchers attribute to the eruption of the Toba supervolcano about 73,000 years ago. Both populations have been completely isolated from each other for about 10,000 to 20,000 years. The Borneo orangutan split off from the common line with the Tapanuli orangutan in the Middle Pleistocene around 674,000 years ago (at that time the Sundaland existed as a land bridge between Sumatra and Borneo).

The first scientific description of the Tapanuli orangutan was made in 2017 by a research team led by Anton Nurcahyo . The complete skeleton of a fully grown male animal was available as a holotype . It comes from the Batang Toru Forest near the village of Sugi Tonga in the Tapanuli Seletan administrative district , and the species was named after the Tapanuli region. The animal was killed by local villagers in November 2013. The description of the new species was preceded by around 20 years of research. In 1997 one of the co-authors, Erik Meijaard , visited the forest region to investigate reports on great apes from the transition from the 19th to the 20th century; According to the researchers at the time, this was outside the range of the orangutans. After this discovery of the southern population of orangutans on Sumatra, further sightings occurred in the period that followed. As a result, an investigation program was initiated in 2005. Later genetic studies showed that the Sumatran orangutans do not form a monophyletic group, as the animals of the Batang Toru forest were closer to the Bornean than to the Sumatran orangutan.

Danger

The species can be considered endangered due to several factors: The population comprises only 800 individuals in a narrowly limited area of ​​around 1000 km². The living space is further restricted by the planned construction of a dam with a storage area of ​​around 100 km², and there are gold mines in the border area. Much of the Batang Toru Forest is under protection, but animals are occasionally hunted and wood is felled in the peripheral area. The IUCN has listed the Tapanuli orangutan in the Critically Endangered category since December 2017 .

literature

  • Alexander Nater, Maja P. Mattle-Greminger, Anton Nurcahyo, Matthew G. Nowak, Marc de Manuel, Tariq Desai, Colin Groves, Marc Pybus, Tugce Bilgin Sonay, Christian Roos, Adriano R. Lameira, Serge A. Wich, James Askew , Marina Davila-Ross, Gabriella Fredriksson, Guillem de Valles, Ferran Casals, Javier Prado-Martinez, Benoit Goossens, Ernst J. Verschoor, Kristin S. Warren, Ian Singleton, David A. Marques, Joko Pamungkas, Dyah Perwitasari-Farajallah, Puji Rianti, Augustine Tuuga, Ivo G. Gut, Marta Gut, Pablo Orozco-terWengel, Carel P. van Schaik, Jaume Bertranpetit, Maria Anisimova, Aylwyn Scally, Tomas Marques-Bonet, Erik Meijaard and Michael Krützen: Morphometric, Behavioral, and Genomic Evidence for a New Orangutan Species. Current Biology 27 (22), 2017, pp. P3487-3498 doi: 10.1016 / j.cub.2017.09.047

Individual evidence

  1. a b c d e f Alexander Nater, Maja P. Mattle-Greminger, Anton Nurcahyo, Matthew G. Nowak, Marc de Manuel, Tariq Desai, Colin Groves, Marc Pybus, Tugce Bilgin Sonay, Christian Roos, Adriano R. Lameira, Serge A. Wich, James Askew, Marina Davila-Ross, Gabriella Fredriksson, Guillem de Valles, Ferran Casals, Javier Prado-Martinez, Benoit Goossens, Ernst J. Verschoor, Kristin S. Warren, Ian Singleton, David A. Marques, Joko Pamungkas, Dyah Perwitasari-Farajallah, Puji Rianti, Augustine Tuuga, Ivo G. Gut, Marta Gut, Pablo Orozco-terWengel, Carel P. van Schaik, Jaume Bertranpetit, Maria Anisimova, Aylwyn Scally, Tomas Marques-Bonet, Erik Meijaard and Michael Krützen: Morphometric, Behavioral, and Genomic Evidence for a New Orangutan Species. Current Biology 27 (22), 2017, pp. P3487-3498 doi: 10.1016 / j.cub.2017.09.047
  2. ^ SA Wich, GM Fredriksson, G. Usher, HH Peters, D. Priatna, F. Basalamah, W. Susanto and H. Kühl: Hunting of Sumatran orangutans and its importance in determining distribution and density. Biological Conservation 146, 2012, pp. 163-169
  3. Gerrit S. Miller: Mammals collected by Dr. WL Abbott on the coast and islands of Northwest Sumatra. Proceedings of the United States National Museum 26, 1903, pp. 437-484 ( [1] )
  4. a b c M. G. Nowak, P. Rianti, SA Wich, E. Meijaard and G. Fredriksson: Pongo tapanuliensis. The IUCN Red List of Threatened Species 2017. e.T120588639A120588662 ( [2] ); last accessed on December 15, 2017
  5. a b Erik Stokstad: New great ape species found, sparking fears for its survival. Science News ( [3] ), last accessed on November 3, 2017
  6. Alexander Nater, Pirmin Nietlisbach, Natasha Arora, Carel P. van Schaik, Maria A. van Noordwijk, Erik P. Willems, Ian Singleton, Serge A. Wich, Benoit Goossens, Kristin S. Warren, Ernst J. Verschoor, Dyah Perwitasari -Farajallah, Joko Pamungkas and Michael Krützen: Sex-Biased Dispersal and Volcanic Activities Shaped Phylogeographic Patterns of Extant Orangutans (genus: Pongo). Molecular Biology and Evolution 28 (8), 2011, pp. 2275-2288
  7. Puji Rianti, Dyah Perwitasari-Farajallah, Dondin Sajuthi, Joko Pamungkas, Alexander Nater and Michael Krützen: Identification of Diagnostic Mitochondrial DNA Single Nucleotide Polymorphisms Specific to Sumatran Orangutan (Pongo abelii) Populations. HAYATI Journal of Biosciences 22, 2015, pp. 149–156
  8. ^ April Reese: Newly discovered orangutan species is also the most endangered. Nature News ( [4] ), last accessed on November 3, 2017
  9. Sean Sloan, Jatna Supriatna, Mason J. Campbell, Mohammed Alamgir, and William F. Laurance: Newly Discovered Orangutan Species Requires Urgent Habitat Protection. Current Biology 28, 2018, pp. R1 – R3 doi: 10.1016 / j.cub.2018.04.082

Web links

Commons : Pongo tapanuliensis  - collection of images, videos and audio files