Posts on Fauna

New Species of Bornean Slow Loris

15 December 2012

The sight of a Slow Loris (Nycticebus menagensis) staring down at you from the rainforest canopy, its eyes brightly illuminated by your headlamp, is always an exciting find. It was only three weeks ago, whilst I was on a nocturnal foray with a group of photographers in the jungles bordering Sarawak and Kalimantan, that I had my most recent encounter with a loris. Unfortunately, these nocturnal primates are nowhere abundant and sightings of them uncommon at best, due in part to patchy distributions and also sadly, capture for the pet trade.

A new paper in American Journal of Primatology presents a dramatic new view of the loris diversity in Borneo. Previously, three subspecies of loris were known from the island: N. m. bancanus, N. m. borneanus, and N. m. menagensis, which differed from each other in fur coloration and body size. However, taking into account other recent findings in loris diversity, the reseachers of the present paper undertook a thorough investigation on the variation of Bornean lorises, which had never been studied in great detail.

After critically examining a number of museum specimens and carefuly comparing their morphology and corresponding geographic locations, they concluded that there were not three, but four distinct loris types on Borneo, and went further to elevate each of these to its own species status. Thus the presently recognized species now include: N. bancanus, N. borneanus, N. menagensis, and the new N. kayan.

Several months ago I received an email from Dr. Anna Nekaris, who heads The Little Fireface Project, a non-profit organization dedicated to loris research and conservation. She pointed out that one of the animals which I had photographed in Sarawak several years ago represented the newly described Nycticebus kayan (pictured below). Specifically, the Kayan Loris can be distinguished from other Bornean lorises by a combination of features including its highly contrasting and distinctive face mask.

Nycticebus kayan

Like all lorises, the Kayan Loris is primarily nocturnal and feeds on a variety of insects and soft fruits. Lorises are also unique among primates in that they possess a venomous bite which is used in self-defense. The bite can cause fever, pain, and swelling, and in people who happen to be allergic the results may even be fatal. One Sarawakian who I met in Mulu National Park, had to be hospitalized for several days after being bitten when handling a wild loris.

Although more research, including genetic studies, remains to be done on Bornean lorises, the new discovery helps not only to shed light on the variations of these nocturnal primates, but also is a testament to the amazing diversity which is continuing to be revealed within Southeast Asian rainforests.

References:

R. Munds, S. Ford, K.A.I. Nekaris. Taxonomy of the Bornean Slow Loris, with New Species Nycticbus kayan (Priamtes Lorisdae). American Journal of Primatology, December 2012; DOI: 10.

Borneo Rainbow Toad Rediscovered

10 July 2012

This time last year Borneo’s amazing biodiversity again made widespread news with the rediscovery of the long lost Borneo Rainbow Toad. In July 2011 researchers from the University of Malaysia Sarawak (UNIMAS) led by herpetologist Dr. Indraneil Das made an extraordinary find in the mountains of western Sarawak. Three small amphibians were observed in the branches of a tree, and upon close inspection these were revealed to be none other than Ansonia latidisca, a species which had not been seen since 1924.

Measuring up to 5 cm in length, this toad is one of the largest and certainly most colorful in the genus Ansonia. Although the dorsum is richly patterned with green, yellow, purple, and brown with red-tupped warts, the general appearance is somewhat “mossy” and this may serve to camouflage the animal from potential predators.

The rediscovery of this species brings some much-needed hope in the face of ever-increasing worldwide amphibian extinctions, particularly as Conservation International had previously listed the Borneo Rainbow Toad as one of the “world’s top 10 most wanted frogs” in their Global Search for Lost Frogs in 2010. Nevertheless, amphibians remain the most threatened group of vertebrates on the planet, with severe threats coming from habitat loss, climate change, and the dreaded chytrid fungus (Batrachochytrium dendrobatidis).

Photographs are still scarce of this elusive species, and little is known of it’s life cycle, behavior, or remaining popultion.

Ansonia latidisca

Halmahera and the Bird of Paradise

9 December 2011

Situated midway between Sulawesi and New Guinea in the tropical marine waters of the Coral Triangle, lies the curious and enigmatic island Halmahera. Although having a similar geology to larger neighbor Sulawesi, being composed of four sinuous peninsulas each with their own distinctive volcanic, karst, and ultramafic rocks, Halmahera is astonishing in terms of its biological uniqueness. At about 18,000 sq km, it is the largest island of the Moluccas (or ‘Spice Islands’), and its rugged and remote interior is still extensively covered with rainforest.

The 19th Century naturalist Alfred Russel Wallace, who spent the better part of a decade traversing the Indonesian archipelago, visited Halmahera (then more commonly referred to as ‘Gilolo’) in 1857-1858 and recognized the island as a complete unknown in terms of its flora and fauna. Whilst basing himself on the nearby volcanic island of Ternate, Wallace made numerous forays onto the mainland and other offshore islands to collect specimens of insects and birds, many of which he noted were completely new to science. One such find was a remarkable new bird of paradise which Wallace considered one of his greatest discoveries and later came to bear his name. It was also here on Halmahera in 1858, that Wallace formulated his own theory of natural selection, independently from Charles Darwin, whilst suffering from a feverish delirium brought on by malaria.

Although not as biodiverse as the Sunda islands or New Guinea, in part due to its smaller size and distance from the mainlands of Southeast Asia and Australia, Halmahera (inclusive of several of its near offshore islands such as Morotai and Bacan) is a veritable hotspot for species endemism. Some notable animal specialties include the Ornate Cuscus (Phalanger ornatus), Sailfin Lizard (Hydrosaurus weberi), and Tri-colored Monitor (Varanus yuwonoi), among many others. But it is the wonderful array of endemic birds for which the island is particularly known, and visiting naturalists often seek out such beauties as the Ivory-breasted Pitta (Pitta maxima), White Cockatoo (Cacatua alba), Invisible Rail (Harbroptila wallacii), and the remarkable Wallace’s Standardwing (Semioptera wallacii).

Gekko vittatus

My time on Halmahera was focused in the Weda Bay region, just below the eastern peninsula, where the clear reef-filled waters are backed by undulating forested hills rising to nearly 1000 meters in elevation. Weda Bay Resort, located on the coast about a dozen kilometers north of the town, kindly hosted me during my visit and provided invaluable support for my field work. This eco-resort consists of a modest set of traditionally-built bungalows primarily catering to divers who come to enjoy the renowned marine life of the bay.

Here I spent several weeks in and out of the jungle and along disused logging roads attempting to discover the island’s many biological treasures. Whilst mammals were scarce (and almost entirely nocturnal), birdlife was incredibly rich and the air was perpetually filled with the harsh piercing calls of cockatoos, parrots, and hornbills. The forests of Halmahera are devoid of any large mammalian carnivores, with the only significant large land predators being snakes. My field assistant Lius, a native of north Halmahera, related to me a personal account of an encounter with a 9-meter Reticulated Python (Python reticulatus) which had killed and swallowed one of his companions in 1977. During my visit the only python we encountered was a Halmahera Scrub Python (Morelia tracyae) consuming a Nicobar Pigeon (Caloenas nicobarica) high in a tree.

Traditional hunting practices in this area appeared to have kept most wildlife fairly shy, and it took considerable effort to observe some species at close range. One of my most sought-after subjects was the legendary Wallace’s Standardwing (pictured below), which until as recently as the 1980’s had been seen only a handful of times in the wild. Like many other birds of paradise, the males of this species own extravagantly ornate plumage and gather at communal display grounds (leks) to compete for the attention of females. To observe the Standardwings at such a site it is necessary to arrive well before dawn, as their display activities begin just before sunrise.

Semioptera wallacii

I will never forget the first morning I spent at a Standardwing lek watching these avian acrobats and listening to their raucous calling. Within the confines of a single small tree crown several male birds had partitioned certain branches as their personal display territories, with younger or less dominant males nearby in other trees. Upon the approach of a female bird, the males would begin their frantic actions, calling loudly and putting on an incredible display which consisted raising four long white plumes on their shoulders and simultaneously expanding brilliant metallic blue breast shields whilst lightly fluttering their outstretched wings. Occasionally a bird would fly straight up several meters and slowly parachute back down to his chosen branch. The visiting female would take her time to select the male she was most impressed with, mate with him and then disappear off into the forest. I found that photographing in the dim pre-dawn light was exceptionally difficult, and not long after the sun had risen all the birds usually dispersed for their daily foraging activities.

I spent nearly a week camped in the rainforest near this site and I never tired of watching these marvelous birds. In the past few decades, many of the known lek locations have been destroyed by logging, and although I could frequently hear the sound of chainsaws in the distance, it was a relief to know that this site had been privately purchased by Weda Resort in order to preserve it.

To view photos taken during my November 2011 trip to Halmahera, click here.

References:

Coates, B.J. & K.D. Bishop (1997) A Guide to the Birds of Wallacea. Dove Publications.

Setiadi, M.I., A. Hamidy, Z. Abidin, D. Susanto, R.M. Brown, A.T. Peterson, X. Li & B.J. Evans (2009) Genetic Structure of Herpetofauna on Halmahera Island, Indonesia: Implications for Aketajawe-Lolobata National Park. Conservation Biology, 24:2, 553–562.

Wallace, A.R. (1869) The Malay Archipelago. Oxford University Press, Kuala Lumpur.


© Ch'ien C. Lee (1996-2012). By using this website you agree to the terms of use. JavaScript required