Primatologist Vincent Nijman traced all the langur photos back to a singe trader in a bird market in East Java.
He argues that the monkeys are ebony langurs that belong to the genus Trachypithecus.
Nijman believes that the orange-golden hair around the faces of the langurs is most likely the result of partial bleaching by traders to attract buyers. Another primatologist refutes this argument and says that partial bleaching would be much less likely to produce such a convincing result.
In 2010, researcher Francesco Nardelli discovered two photographs of a certain species of langur, or leaf monkey, on the internet that he could not recognize. The caged langurs in the photos — which had been taken in a bird market in East Java in Indonesia — had black faces outlined by distinctive orange-golden colored hair.
Over the next five years, Nardelli combed through zoo records, museum specimens, and published literature to resolve the identity of the langur. Then in October this year, in a paper published in the journal International Zoo News (IZN), Nardelli concluded that the langur in the photos was indeed a new species. He named it the golden-crowned langur, or Presbytis johnaspinalli.
However, soon after Mongabay broke the news of the new langur species on October 23, some primatologists challenged Nardelli’s conclusions. One of the critics, Vincent Nijman, a primatologist at Oxford Brookes University who has worked on Presbytis and Trachypithecus monkeys for over two decades, recently published his arguments against the status of the langur species in the journal International Zoo News.
Like Nardelli, Nijman investigated the origin of the photographs and traced the source of all photos — including two additional ones that he found online — back to “most likely a single trader [Mr M. Sabar] in the Ratu Soerjo bird market (a.k.a. Mantingan bird market) at the outskirts of the town of Mantingan in the Ngawi regency in East Java close to the border with Central Java.”
All seven photos found so far, Nijman said, seem to have been taken sometime in 2009. Nijman added that the caged langurs were photographed by members of the Indonesian NGO ProFauna, by officers of the nature conservation agency responsible for the confiscation of the langurs from the Javan bird market, or journalists who were either present in the market at the time of confiscation, or who later visited the agency’s office in Surabaya where the animals were stored.
Based on these findings, Nijman agrees with Nardelli that the langurs most likely originated from Indonesia’s forests. However, he has several points of contention.
Nardelli’s langur may not be a new species
Nijman believes that Nardelli’s langur is not a new species belonging to the Presbytis genus as Nardelli concluded in his paper. Instead, Nijman writes that the monkeys are most likely ebony langurs, also called Javan lutungs, that belong to the genus Trachypithecus.
Ebony langurs are found in the tropical forests of Indonesia, on the islands of Java, Bali, and Lombok, and occur in two predominant colors—black and yellowing orange.
The main point of difference between the two genus, Nijman writes, is that “the hair on the top of the head forms a distinct crest or tuft in Presbytis whereas in Trachypithecus it can also be seen pointing forward as to form a pronounced fringe.”
“I think it is fairly clear that this is a Trachypithecus langur, not a Presbytis, and there is nothing that in my mind suggests that this is a new species,” Nijman told Mongabay.
Douglas Brandon-Jones, an expert on langur taxonomy, agrees with Nijman.
“The cranial anatomy underlying the naked skin of the face in my view unequivocally identifies the monkeys as Trachypithecus, not Presbytis,” Brandon-Jones told Mongabay.
He added that since the langurs were being sold in a market in Java, Indonesia, that is where the photographed langurs most likely originated from.
“There is a fairly large area in Southeast Java where the T. auratus population may be entirely orange,” he said. “Specimens that are not entirely orange exist in museums. None that I have seen match Nardelli’s monkeys in extent of black, but it is very likely that such specimens occur on the boundary of the area where most, if not all are orange. I therefore reject these monkeys as a new species. Instead they are merely intermediates between the black and the orange morph of T. auratus.”
Were the caged monkeys partially bleached by traders?
Nijman believes that the orange-golden hair around the langurs’ face and chest is most likely the result of traders bleaching the animals to attract buyers. According to Nijman, artificially colored animals are common in Indonesian animal markets.
“It is so common that we see at least some bleached or dyed animals in at least the larger markets,” Nijman said. “It is impossible to miss once you are aware of it.”
Nijman added that it is common to see rabbits and chicks in Indonesia’s animal markets that have been dyed pink, yellow or green. Nijman and his colleagues have seen wild animals like common palm civets that have been dyed black, slow lorises that have been dyed black or bleached, long-tailed and pig-tailed macaques that have been bleached, as well as other Presbystis and Trachypithecus langurs that have been bleached or artificially colored.
Mongabay contacted Nardelli for his comments. But Nardelli declined and said that he hoped to publish a “comprehensive answer to Prof Nijman’s challenges” in a journal soon.
Nardelli had previously claimed though, to have “never come across artificially colored mammals” in over ten years of his work in Indonesia.
Brandon-Jones disagrees with Nijman, and argues that bleaching would not produce very convincing results.
“I reject this possibility because one of the photographed juveniles clearly shows a line of black hairs along the upper facial margin,” he said. “If you were bleaching these monkeys it would be virtually impossible to leave this line intact. I cannot imagine a monkey submitting to such treatment without struggling so one would expect the ‘bleached’ area to be much more irregular than it is.”
“It would perhaps be possible for someone to completely immerse an animal in bleach to turn it blond, but for the above reasons, partial bleaching would be much less likely to produce a convincing result,” he added. “Most people are so ignorant of the distinctions between different species that I see no motive for such a time-consuming and potentially dangerous deceit. I suspect these critics may be mistaken in concluding they had seen many bleached animals. I have seen some partially bleached museum skins, but it is clear they were bleached after death in the course of the preparation process.”
Whether traders bleached the langurs to attract buyers is still up for debate. However, many experts agree that the monkey is probably not new to science.
“I am sorry for Dr Nardelli, but it seems very likely that he and his colleagues got things wrong,” Erik Meijaar, Director of Borneo Future had said in response to Mongabay’s initial coverage of the ‘new’ langur species. “Think about it, what are really the chances that 200 years of zoology had overlooked a very distinctive looking new primate species. We are not talking a new rat, like the recently discovered Sulawesi hog-nosed shrew rat, or obscure bird, but a leaf monkey, which, considering the distribution of leaf monkeys, could only derive from the most densely settled parts of Indonesia.”
- Nijman V (2015) Newly described Golden-crowned langurs Presbytis johnaspinalli are most likely partially bleached Ebony langurs Trachypithecus auratus. International Zoo News Vol. 62. No. 6 (2015), pp. 403-406.