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New mammals in the 21st century? |
July 1, 1999. |
by Prof. John MacKinnon
University of Kent, U.K.
After fifty years in which only one new large mammal had been found worldwide, three new ungulates were found in the same region of Vietnam within four years. The context of the finds is discussed in relation to the continuing finds of other mammals and birds. MacKinnon draws conclusions about the types of places that may still conceal undiscovered mammals and predicts where future finds will be made into the next century.
Ever since Linnaeus began describing and counting the species with which Man shares the Earth, the numbers of known species has continued to grow. For some groups the species discovery curve continues to rise steeper and steeper but for the warm-blooded vertebrates, especially the large mammals, the curve is levelling, and we can hazard some guesses as to how many more species there are to find.
During the first three decades of this century only a handful of new large mammals were discovered. The finding of okapi Okapia johnstoni in 1901 in the forests of Congo created enormous popular interest and speculation that this was the last great new mammal. But other new African finds were quickly made—the pygmy hippo Choeropsis liberiensis, giant forest hog Hylochoerus meinertzhageni in 1904, and Mountain Nyala Tragelaphus buxtoni in 1910 before the African vein started to dry up. In 1937 Urbain described the Kouprey Novibos sauveli—a large ox of Cambodia, but actually found in a zoo in Paris! During the next 50 years, hardly any new large mammals were found. The Chaco Peccary Catagonus wagneri, already known and named from fossils was found to be still extant and a few new species were added by taxonomists splitting known forms—African colobine monkeys, Sulawesi macaques, and others. Some zoologists believed that the large mammals were, by and large, all in the museum.
Discoveries of new birds have also been scarce. 98% of all Palearctic birds were described between 1758 and the turn of this century. Only seven new Palearctic birds have been described since 1920 with five of these being in the less explored regions of China. Moreover, three of the seven finds lay for years unrecognized in museum collections before being recognized as new.
In 1992, however, a completely new large mammal was found in the North Annam mountains in the Vu Quang Nature Reserve of Vietnam—the Saola or Vu Quang Ox (figure 1). The species was given its own genus Pseudoryx and DNA showed that it was a primitive member of the cow and goat family Bovidae. Two sets of the unique horns were found hanging in as hunter’s trophies in a Vietnamese village. Subsequent morphological and genetic studies have shown that the animal is so unlike anything else that it should be regarded as a new sub-family. A great amount of media interest was devoted to the find but it took two years before anyone actually saw the animal alive.
Evidence of thenewly discovered Soala. Prof. John MacKinnon with the first sets of the Saola Pseudoryx nghetinhensis found in Ve Quang.
The find was exciting for several reasons. It caused a complete revision of the taxonomy of the family bovidae. It helped highlight the conservation status of the neglected Annam Mts. region but most of all it made people realize that we really do not know all our large mammals and it is still worth looking for more.
Both Saola and Giant Muntjac were also found in Laos and wider searches in the Annamite Mountains revealed a new pygmy muntjac Muntiacus truongsonensis and in Laos, the rediscovery of Roosevelt’s Muntjac (previously known from only one specimen) as well as rediscovery of a bearded pig Sus bucculentus (previously known from only one lost specimen in Shanghai Museum). A new striped rabbit was also found in Laos (Nesolagus) (formerly thought to be a Sumatran endemic genus) and has now also been found in Vu Quang and Pumat reserves in Vietnam and still awaits scientific description. Another small muntjac has also been found in the central Annam Mts. of Vietnam awaiting analysis and description. Vu Quang, itself, continues to reveal novelties. Two new species of fish have just been described there.
The exciting new discoveries in Vietnam and Laos seemed to stimulate a new wave of search and discovery around the world. A new antelope Pseudonovibos spiralis was described from Cambodia on the basis of several sets of unique spiralling horns. Though, the failure of efforts to find the animal alive suggest we may be too late to save this species. A new Tree Kangaroo (the bondegezou) was discovered in the Jayawijaya Mountains of Indonesian New Guinea. No less than seven new marmosets (the latest being Callithrix mauesi and C. nigriceps) were added to the mammals list in Brazil. Two new bushbabies, Galaoides rondoensis and G. udzungwensis, have been described from Tanzania. A new horse was reported from Xinjiang, China. Even new claims of sightings of Himalayan Yeti (Bhutan) and Sumatran Orang Pendek and the Hubei Wild Man of China have been all appeared in the recent Press.
Are we on a new wave of discovery? Or is this all just journalist hype? In fact the discovery of new mammals has been rather steady throughout the century and more than a hundred new mammals have been described without attracting much public attention. These have been largely bats, rodents and insectivores, or cases of splitting up previously recognized taxa such as the Sulawesi macaques and Sulawesi tarsiers.
The Annam mountains do seem to be a rich and still not fully explored vein of diversity; one of the world’s overlooked ‘biodiversity hotspots’. The spectacular mammals finds are largely a time warp in an area where zoological exploration had been held up for 50 years due to constant warfare and political trouble. But the finds do give us clues about where to still find new species.
Despite being in one of the most populated regions of the earth and a region heavily devastated by both chemical and physical bombardment during the Vietnam War, the North Annam mountains are rugged, difficult to access, unattractive for agriculture, and ecologically isolated from much drier surrounding lowland forests. Highland peaks are small and separate like a small archipelago of evergreen montane islands. The region is part of an evergreen tropical continental system which has enjoyed climatic stability for thousands of years and where climatic oscillations of the Pleistocene could be easily accommodated by species by making minor vertical movement in the steep terrain.
These are conditions ideal for both the creation of local endemic species and for the survival of primitive and relict forms. The region is both a classic Pleistocene refuge and a source of new radiation.
The following key characters, can be identified as related to the likelihood of a given area still hiding undiscovered forms (figure 4):
Most of the localized endemic vertebrates of Asia occur in montane or insular areas—Western Ghats, SE China mountains, Central China mountains, Mt. Kerinci (Sumatra), Mt. Kinabalu (Borneo), Taiwan, Mt. Victoria (Burma), West Javan Mountains, Sulawesi, Philippines and Mollucan islands, and others. Contrast these with the generalized Asian large mammal fauna of elephant Elephas maximus, tiger Panthera tigris, leopard Panthera pardus, gaur Bos gaurus, wild boar Sus scrofa, sambar deer Cervus unicolor and red muntjac Muntiacus muntjak, which occur all the way from NW India to Borneo through a huge range of altitudinal and rainfall differences. These latter animals probably constitute a fauna that has followed man south and east through Asia, benefitting from his opening and burning of the forests and displacing the original, more evergreen forest fauna. Glimpses of this richer fauna can be seen in the fossil record of the Siwaliks of N. India.
In Africa, one also finds that endemism and species richness is concentrated around relict evergreen mountains and Pleistocene refugia—West African rainforest, Mt. Cameroon, Eastern Rift forests and E. Tanzanian forests and mountains. The huge forests of the Congo basin and the huge savannah plains of East and Southern Africa have little endemism.
The new mammals of the 21st century will be found in the still unexplored regions that meet these isolation criteria and that tend to be tropical and evergreen systems and within the regions of high species diversity or endemism. Such unexplored areas remain in NE India, Burma, Laos, SE Tibet, NW Yunnan, S. Philippines, New Guinea, fringing mountains of the Amazon Basin, isolated mountains of C America and smaller neotropical drainage systems.
In addition there are many new descriptions to be made among the lesser explored taxa—the less spectacular and more difficult small mammals. Birds are much better known than mammals because they are mostly diurnal, can mostly be recognized in the wild at long range or by vocalization, and because the world is swarming with rather professional amateur birdwatchers. In contrast, most small mammals are nocturnal, live in holes, and are very difficult to identity. In addition, they bite and can smell and avoid you.