New Species from Batang Toru
Researchers from Indonesia and nine different countries identified the third species of the world’s orangutan living in the forests of Tapanuli, North Sumatra. The species’ population is nearing extinction.
Puji Rianti grew more curious. Results from genetic analysis she did for her doctoral degree in the Evolutionary Genetics Group at the Department of Anthropology, University of Zurich, Switzerland, revealed a major distinction between the orangutan in the forests of Batang Toru, Tapanuli, North Sumatra and their cousins in the northern areas.
The distinction was so apparent that the Batang Toru orangutan seems to be isolated from the Sumatran Pongo abelii orangutan species. "There are 10 to 20 different locus compared to the population of other Sumatran orangutan," Puji said in her office at the Biology Department of the Mathematic and Science Faculty of the Bogor Institute of Agriculture, West Java, last week.
Puji’s genetic analysis, which started in 2009, is part of a joint research on primate genomic-genetic, morphology, ecology, and behavior conservation involving 37 researchers from 35 science institutions across 10 countries.The report, titled Morphometric, Behavioral, and Genomic Evidence for a New Orangutan Species was published in a prestigious science journal Current Biology two weeks ago. This means the new species of orangutan from Batang Toru with its scientific name of Pongo tapanuliensis has been acknowledged by the international science community.
Ian Singleton, Director of the Sumatran Orangutan Conservation Program (SOCP) of the Lestari Ecosystem Foundation, said that in the world, only the Democratic Republic of Congo has three different species of great apes, and now Indonesia has become the second country. "North Sumatra is the only province that has two species of orangutan," said Singleton, who also participated in the research during a press conference at the environment ministry two weeks ago.
The determination of the new species increased the number of the world’s great apes species up to seven, namely: Highland gorilla (Gorilla gorilla) and lowland gorilla (Gorilla beringei); chimpanzee (Pan troglodytes); bonobo (Pan paniscus); the Kalimantan orangutan (Pongo pygmaeus); the Sumatran orangutan (Pongo abelii); and the Tapanuli orangutan (Pongo tapanuliensis).
Sri Suci Utami-Atmoko, a researcher at the Primate Research Center of the National University Jakarta, said that the research did not discover a new species of orangutan, but applied a new classification based on research due to improving research technology. According to Sri, orangutan has long been known to be present in the Batang Toru forest, which covers three regencies in Tapanuli. "At first there was information from local residents. Then in 1997, our colleague from the Netherlands, Erik Meijaard, conducted ground checking," Sri said.
Later in 2003, Suci, Ian Singleton and Serge A. Wich from Liverpool John Moores University, England, surveyed wild orangutan population in Sumatra. In Batang Toru, which is located south of Lake Toba, they discovered a nest of orangutan. The discovery was later published in the Oryx science journal.
The discovery of the Batang Toru orangutan population gained attention from researchers, including behavior researchers of the Orangutan Foundation International in Sibualbuali, North Sumatra. "Ever since we’ve developed a strategy and action plan to conserve orangutan, Batang Toru started to become separated in the analysis because it requires extra work [in the region]," said Suci, who was not involved in the writing of the report in the Current Biology.
Genetic research was also carried out using conventional technology, which requires samples from the orangutan’s feces and hair. According to Suci, in 2011, in a research conducted by Alexander Nater, who is the main author of the Current Biology report, it can be seen that the male orangutan in Batang Toru have more similarities with the orangutan in Kalimantan compared to other orangutan in Sumatra.
The distinctiveness of the Batang Toru orangutan was discussed in an international seminar held at the National University, Jakarta, in 2013. "But back then, the sample was not enough to prove whether the Batang Toru orangutan is a sub-species, or a new species," said Suci, a lecturer at the Biology Post-Graduate School of the National University who is nominated for the animal conservation award at the Indianapolis Prize 2017.
Problems related to the lack of samples was addressed through Puji Rianti’s research, which used orangutan’s DNA mitochondria, Y chromosome, and micro-satellite marker or repetitive DNA core sequence marker. Puji’s genetic research was later complemented by her colleagues Alexander Nater and Maja P. Mattle-Greminger by conducting a genomic analysis on a Sumatran orangutan and comparing the results with the Kalimantan orangutan. They discovered significant differences between the Batang Toru orangutan and two other species. However, the genetic proofs is considered to be inadequate, leading them to conduct a morphometry research to discover differences in terms of bone size and body measurements.
Anton Nurcahyo, an Indonesian researcher who is currently taking his doctoral studies in the School of Archeology and Anthropology at the Australian National University took part in the research. Anton compared bone sizes of 33 male orangutans collected from 10 specimen storage agencies around the world with the skeleton of the Batang Toru orangutan stored at the Zoologicum Bogoriense Museum in the Indonesian Institute of Sciences (LIPI) in Cibinong, West Java.
"What a coincidence that there was a report of an orangutan who died because of conflict with local residents near Sugi Toga, Marancar, South Tapanuli, in the Batang Toru forest areas on November 2013," Puji said.
According to Yenny Saraswati, a Senior Veterinarian at the Sumatran Orangutan Conservation program quarantine area, Raya, the orangutan, was rescued from severe injuries caused by torture, and was treated for one week before finally died. For scientific purposes, the remains of Raya was later handed over to LIPI in 2016.
Anton used Raya’s skull and skeletons as comparison to the 33 other research samples. Puji asserted that the difference was apparent. Raya’s skull and jaw bone size were smaller compared to two other orangutan species.
The determination of Pongo tapanuliensis as the third orangutan species is under threat of extinction. Its population is estimated to be less than 800, divided into three habitat blocks within the Batang Toru ecosystem, which covers a total area of 150,000 hectares. "Ironically, the highest population is in the western block, with 400 orangutans, the status of the areas is listed as open for other purposes and is not protected by the government," Suci said.
Director-General of Natural Resources and Ecosystem Conservation at the Environment Ministry, Wiratno, said that there has to be an effective management of the Batang Toru areas supported by the public, government, and non-governmental association. "We will conduct a public dialogue to discuss options to determine the Batang Toru ecosystem area as a protected forest or animal sanctuary, or to develop three corridors connecting each block [of Batang Toru]," Wiratno said.