The discovery was made with the invaluable help of local villagers as part of the Elasmobranch (shark and ray) Biodiversity, Conservation and Management project being carried out by the IUCN Shark Specialist Group in Sabah. This 18 month study, which is funded under the UK Darwin Initiative for the Survival of Species, has been underway since January 1996.

Until last month, the Borneo River Shark (known to scientists simply as Glyphis species B') was recognised from just one preserved specimen found in a museum in Vienna, taken from an unknown river in Borneo over 100 years ago. However, a small shark caught by fishermen earlier this year was kept for the Shark Specialist Group survey team by a family in a small riverside kampong (village) of Sabah. Several other juvenile River Sharks caught in the same net were photographed by the fishermen before being discarded.

The excitement of those who were shown the shark was intense. Darwin Project officer Mabel Manjaji and UK volunteers Rachel Cavanagh and Scott Mycock reported their delight over the find: ''The family led us to the tank of formalin which they had been keeping locked up at the back of their stilt house, insisting that they had a shark for us in there. They looked on in bewilderment; we could barely contain ourselves - could it really be Glyphis? We all crowded round as the tank was opened, oblivious to the formalin fumes. 'It looks like Glyphis can it really be? It is!' There it was, black beady eyes, blunt snout, fins like we'd never seen before but just like those in the books - there was no doubt about it: this was Glyphis, at last!''

Shark Specialist Group international expert, Dr Leonard Compagno, Curator of Fishes and Head of the Shark Research Center, South African Museum, has studied the few existing museum specimens of this group, most of which were collected in the 19th Century. Compagno remarks: ''We have very little idea of the geographic distribution of these sharks, much less their general biology. They show up like ghosts, few and far between, in a handful of scattered localities. ''External differences between the known species are subtle; I'd hesitate to place the Kinabatangan shark to species without examining it, but whether it is the Borneo River Shark or another species of Glyphis, this is a remarkable discovery.''

Sarah Fowler, Co-chair of the IUCN Shark Specialist Group, and the UK leader of the Darwin project, was delighted at the news. ''When I first contacted the Department of Fisheries in Sabah, asking them to collaborate on a project to study sharks and rays in Sabah's rivers, they may have thought I was mad. No river sharks or stingrays had ever been recorded in Sabah by scientists, although local fishermen told me that they existed. After a year, I was beginning to think that we would never find any - perhaps they were already extinct in the region? However, the enthusiasm of the Fisheries Department for the project continued unabated, and at last we have been shown that the villagers were, naturally, right all along.

''Fortunately the wet weather last year did not interrupt the remainder of our work programme. Regular visits to coastal fish markets have resulted in the collection and curation of a wide range of sharks and rays from the coastal waters of northern Borneo. Discoveries include some sharks which are completely new to science, as well as new species records for the region. This area has been confirmed as one of the international centres of shark and ray biodiversity.''

The Borneo River Shark is the rarest of the very scarce freshwater species of sharks and rays for which the Shark Specialist Group survey team has been searching for over a year. The researchers were beginning to believe that the occasional reports of a freshwater shark whose description appeared to match that of the almost mythical Borneo river shark would never be substantiated. Heavy rainfall and continual river flooding severely hampered fieldwork in 1996, preventing researchers and local fishermen from fishing successfully for river sharks and rays. Only a single small specimen of the giant freshwater stingray (Himantura chaophyra) was obtained. But, as the river level eventually began to subside last month, the message came in from one of the villages along the Kinabatangan River that a specimen had finally been caught.

The collection of sharks and rays made during the Darwin project will be retained in Sabah for future research. It represents a unique resource for biodiversity and taxonomic research in the region. Duplicate specimens will be housed in other international fish collections, probably including the Natural History Museum in London.