WWU researcher assists in discovery of two new tarsier species in Indonesia

Wednesday, May 3, 2017 - 10:24am

Myron Shekelle, research associate at Western Washington University’s Department of Anthropology, is involved in an Indonesian study that has identified two new species of tarsiers - small nocturnal primates found only on several islands of Southeast Asia.

The scientific description of two new tarsier species will be posted online in the journal Primate Conservation on May 4.  Tarsiers are widely rumored to have been the inspiration for the Star Wars character, Yoda.  As such, a group of primatologists have designated May 4 as International Tarsier Day, and planned the release of the descriptions to coincide with that day, which many young people refer to as Star Wars Day (May the Fourth be with you!).

Tarsiers are most closely related to the anthropoid primates, a group that includes monkeys, apes, and humans, but they separated from that group 64.2 to 58.4 million years ago according to genetic data.  A typical adult male weighs about 120 g (4.3 oz), or about the same as a stick of butter.  Adult females often weigh about 10% less.  Tarsiers have the largest eyes relative to their body size of any mammal.  Each eye ball is approximately as large as their brain.  Like owls, tarsiers can turn their head more than 180º in either direction.  They have the longest legs relative to their arms among all primates, as tarsiers are the primate that is most highly adapted for leaping, and can easily leap 3 meters.

Tarsius spectrumgurskyae and Tarsius supriatnai, from the provinces of North Sulawesi and Gorontalo, respectively, are each named for a pivotal scientist in Indonesian conservation.  Dr. Sharon Gursky, Professor of Anthropology at Texas A&M University, has been the world’s foremost expert on tarsier behavior for more than 20 years.  Jatna Supriatna, professor of Biology at the University of Indonesia, was the director of Conservation International’s Indonesia office for 15 years, and has sponsored much of the scientific research on conservation within that country.  Like many nocturnal species, these two species look similar to each other, as well as other tarsiers, but are diagnosed mainly by their vocalizations and genetic data.

 

The discovery of these species is expected to help conserve the critically important regions in which they are found.  Indonesia harbors a disproportionate percentage of the world’s biodiversity.  The island of Sulawesi is rich in species found nowhere else on earth.  It is the world’s 11th largest island.  It is the largest landmass within the conservation hotspot of Wallacea.  Lying between Asia and Australia, it has many Asian species, such as monkeys, and also Australian marsupials, such as cuscus.  More interestingly, it holds several species that are most closely related to animals from Miocene epoch, and which sheltered in the isolation of Sulawesi and other nearby island groups.  Tarsiers are among these.

Along with Shekelle, the authors of this study include lauded conservationist, Russell Mittermeier, founder of Conservation International, one of the world’s largest conservation organizations.  Ibnu Maryanto is a senior scientist at the Indonesian Institute of Sciences. Professor Colin Groves, of Australian National University, was referred to by Jane Goodall as the world’s greatest living primate taxonomist.  Shekelle has been studying the evolution of tarsiers for 23 years.  His work has helped with the recognition that tarsiers on Sulawesi are not just one or two species, as was widely believed when his work began, but a cluster 16 or more.  With these descriptions, the number of recognized species from Sulawesi and nearby islands rises to 11.  The same authorship group has at least two more species in the process of scientific description.