Tuesday, July 3, 2007

World's Smallest Fish In Sumatra

Scientists Discover World's Smallest Fish In Sumatra

When talking about fish, size is the most important thing. The bigger the fish, the better the tale the fisherman will tell for years to come. But scientists are a peculiar type of fishermen, as they’ve discovered the world's smallest fish in a tropical acidic swamp where the water is the color of strong tea. Females grow no bigger than 7.9mm (0.31in) and the male measures up to 10.3mm.

Scientists had thought that little if anything could survive in such peat swamps but have been astonished to discover several species of small fish including the latest specimen, named Paedocypris progenetica. A Swiss biologist, Maurice Kottelat, and Tan Heok Hui from the Raffles Museum of Biodiversity Research in Singapore, discovered the fish by sieving the water of the Sumatran swamps with a fine-mesh fishing net.

They sent specimens of the fish to the Natural History Museum in London where Ralf Britz, a zoologist and fish expert, identified it as a species new to science.

Dr Britz said that it was a member of the carp family. The males were distinguished by having a pair of large pelvic fins which were manipulated by well-developed muscles. "This is one of the strangest fish that I've seen in my whole career. It's tiny, it lives in acid and it has these bizarre grasping fins," Dr Britz said. The peat swamps on Sumatra were extensively damaged in 1997 by forest fires and are threatened by logging, the growth of towns and agriculture. Several populations of the tiny fish have already been lost, he said.

"I hope we'll have time to find out more about them before their habitat disappears completely," Dr Britz said.

The forest swamps of Indonesia were once thought to harbour very few animals but recent research shows that they have a rich and diverse range of wildlife that appears to be unique to this habitat. "These forest swamps harbour an unusually large number of species. The water is poor in minerals and this may restrain bone growth leading to the adaptation of being small," Dr Britz said. Adult Paedocypris fish are transparent and resemble juvenile larval fish despite being sexually mature, with males sporting the well-endowed pelvic fins.

Unique among fish, males of the species have pelvic fins with tough pads on the front, which may help to hang on to females during mating, the researchers propose.

Paedocypris has many "larval" features, such as a rudimentary skull that leaves the brain exposed. Evolutionary pressures may have prompted the fish to develop special fins to survive its environment, the team reports.

The "tiny and bizarre" fish is also the smallest known freshwater vertebrate, the team said.

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