New dwarf monkey species discovered

Researchers came to new species by their song on the track

The new dwarf monkey species betrayed itself by her singing © Stefan Merker
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An international research team has discovered a new species of pygmy monkey in the rainforests of Sulawesi. The Tarsius wallacei baptized leprechaun males betrayed their presence by their singing, which differed markedly from that of the known species. Gene analysis of the monkeys also revealed surprising differences between two populations that live only slightly apart, as the researchers report in the International Journal of Primatology.

Huge eyes, big ears and long, thin fingers and toes make the little twelve-centimeter leprechauns look like cuddly toys. The nocturnal insect hunters live in the undergrowth of the Southeast Asian rainforests and are among the smallest primates of Asia. Nine species have been known so far. The biologist Stefan Merker from the Goethe University was able to identify a tenth species together with German, Indonesian and American colleagues. The researchers named the new species Tarsius Wallacei in honor of the British naturalist Alfred Russel Wallace (1823-1913). Wallace discovered about the same time with Charles Darwin evolution by natural selection.

The discovery is significant because the leprechaun males (or tarsiers) are closer to us humans in evolution's pedigree than Madagascar's lemurs, some of whom occupy a similar ecological niche as their distant Southeast Asian relatives. The ancestors of the leprechaun mackerel probably separated themselves from all other primate groups living today about 60 million years ago, and this long evolutionary solo pass has left its mark on the few species we know today.

Different vocals betrayed new style

Merker and his team came on the trail of the new species during their field work on the Indonesian island of Sulawesi. There has developed the largest variety of leprechaun mackerels. The Sulawesi Tarsiers live in small family groups, who communicate in the morning with characteristic duet songs when they retire to their sleeping trees. Already in 2006, when Merker examined two other species, he noticed the different song of the animals southwest of the city of Palu in Central Sulawesi. Two years later, supported by the German Research Foundation, he was able to investigate the question of the identity of these unknown primates. As part of a larger project, 15 of the animals were caught and examined.

Two separate populations

The genetic analysis clearly indicates that the animals are highly different from the previously known species. The calls and some of the morphological features are also unique. A surprise for the biologists, however, was the distribution of the new species: it occurs in two geographically isolated populations, a large northern and a small southern group. These are separated by the provincial capital Palu with their houses, plantations and rice fields - but also by the occurrence of another Koboldmaki species. display

After initial analyzes, Merker expects isolation of the two populations several tens of thousands of years ago, and a more precise dating of the separation is soon to follow from the study of more animals. The current spread of the Wallace leprechauns is not consistent with our hypotheses. We want to get to the bottom of this departure from our theory as soon as possible, "Merker said.

Destruction of the habitat threatens

Like many other rainforest species, leprechaun males are also severely affected by the destruction and fragmentation of their habitat. Especially the southern population of the newly discovered species is facing an uncertain future. Merker estimates that the animals live on a surface of at most 10 x 5 kilometers. In addition, as her habitat is severely degraded by human use of the forest, the biologist pledges that, following the classification of the animals that has now taken place, population size and degree of endangerment should be estimated as quickly as possible: In particular, it is important to sensitize the local people to their natural treasures. Species conservation measures should take effect quickly, otherwise it may soon be too late.

(Goethe-University Frankfurt am Main, 24.11.2010 - NPO)