By Richard Gray, Science Correspondent, The Daily Telegraph
Picking his way slowly through the dense tangle of forest undergrowth, Dr Andy Marshall almost missed the venomous snake ahead of him. If he had, he might have lost out on one of the most exciting discoveries of his career. As he searched for a rare species of monkey in the jungles of Tanzania, the young biologist’s eyes were fixed on the trees above him rather than the shrubs around waist height. Until, that is, the green and brown twig snake, coiled around a branch, suddenly moved, spitting something on to the ground in front of him. It was a pale, four-inch long lizard.
At that moment, Dr Marshall, a conservationist at York University, had discovered a new species. The lizard that had so nearly become dinner for the twig snake turned out to be an unknown species of chameleon. “Twig snakes are not easily frightened,” he explains. “Perhaps because this one had something in its mouth it felt vulnerable, and fled.
“It had been in the process of eating the chameleon and had almost all of it in its mouth when it spat it out. I knew it was something I hadn’t seen before, so I took a photograph and later showed it to a herpetologist. He said right away it was something special.”
Dr Marshall has since named his new species Kinyongia magomberae, which means the chameleon from Magombera, the forest where it was found.
While not the most conventional way of discovering a new animal, the find afforded Dr Marshall a part in the centuries of work that have resulted in around 1.2 million of the world’s species being identified by science.
Those outside of the closeted world of taxonomy, the area of biology tasked with identifying and naming new species, would be forgiven for having thought the majority of life had by now been discovered. But the debate about exactly how much life is out there continues to rage. Last week, scientists at the World Conference on Marine Biodiversity in Aberdeen announced a new estimate for the number of species on earth – just two million.
Dr Mark Costello, from the University of Auckland, said that, according to his research, we will have discovered all of the species on earth by the end of the century.
However, last month, scientists from the University of Hawaii and Nova Scotia’s Dalhousie University claimed to have made the most accurate prediction and put the figure at 8.7 million species, plus or minus a million.
If they turn out to be right, then we have barely scratched the surface of what is left to be discovered. And this figure does not include bacteria, of which there are undoubtedly many more million species. Even discounting the bacteria, it means that up to 90 per cent of the world’s species remain undiscovered. Some experts have estimated it could take more than 1,000 years to catalogue them all.
Enter the species hunters. Unlike the gentleman naturalists of Edwardian and Victorian times, they are armed with digital cameras, satellite phones, laptops and an encyclopedic knowledge of taxonomy. Jonathan Timberlake, of the Royal Botanic Gardens in Kew, who has led several expeditions in search of undiscovered life, says: “We are still coming back with dozens of new species on every trip.”
On two recent expeditions to the mountains of Mozambique, Timberlake and his colleagues found at least 36 species of plant, seven species of butterfly, a forest viper and a species of chameleon – all new discoveries.
An American organisation called Conservation International has conducted more than 20 surveys over the past two decades, and has collected more than 1,300 new species, including the walking shark, from Indonesia, the ET salamander and the Satanic leaf-tailed gecko, from Madagascar. Indeed, biologists in some parts of the world are turning up hundreds of new species every year.
In these hotspots, such as Papua New Guinea, Madagascar, Borneo, the Congo and the Amazon basin, there can be big surprises. “We are even still discovering new primate species, which we should know better than any other group,” says Dr Ben Collen, head of the Zoological Society of London’s indicators and assessment unit. Since 1998 more than 1,100 species have been discovered in Papua New Guinea alone. Among them are a whiskered marmoset called the Mico acarienaia and a blue reptile known as Varanus macraei.
In 2003, a monkey called a Kipunji was found in the highland forests of Tanzania. Not only was this animal entirely new to science, it also belonged to a new genus of primate. Another major mammal discovery occurred when conservationists working with the World Wide Fund for Nature in Vietnam found unusual skulls in the house of a local hunter. When they eventually caught a live specimen, they found it to be an new species of antelope, now nicknamed the Asian unicorn, or Saola.
The discovery of hitherto unknown species is also being driven by technology. Advances such as DNA bar-coding have allowed scientists to identify new species that in that past would have been impossible to tell apart from existing ones. In one example, a species of woodwhite butterfly that lives in the UK was found to consist of three separate species. Similarly, Britain’s most common bat, the pipistrelle, was recently found to be formed of two species.
Camera traps can capture images of nocturnal creatures, such as the elusive Goodman’s mouse lemur, from eastern Madagascar, that would not normally be seen. Researchers also caught a first glimpse of the Sundaland clouded leopard in Borneo using such traps.
Advances in sound equipment also assist in finding new species. Bat expert Alana Maltby was recording the calls of bats in Papua New Guinea when she noticed some she did not recognise. She says: “One looks like a small mouse, but the other one has a distinctive leaf on its nose. I hadn’t been looking for new species, but because I was recording the calls and matching them to bats, I spotted something unusual.”
Some discoveries can turn up in your back garden. In Kent, a few miles from where Charles Darwin lived for more than 40 years, Dr Andrew Polaszek has discovered two new species of parasitic wasp in a tree 200 yards from his home in Sevenoaks. The insects, which have yet to be named, lay their eggs in the bodies of whiteflies that live on Norway maple.
“I suspect the number of species out there is a lot higher than 8.7 million,” says Dr Polaszek. “There are a lot of cryptic species that can only be unravelled using molecular techniques. When we start looking at the deep oceans and remote islands, we will find so much more.”
Water covers more than 70 per cent of the globe and is on average more than 2.7 miles deep. Little of the ocean floor has been explored, owing to the difficulties in reaching those depths, but already a huge variety of life has been found around hydrothermal vents and on the carcases of dead creatures.
The Census of Marine Life, a 10-year project to catalogue as many species as possible in the world’s oceans, discovered more than 6,200 new species, and the scientists taking part predicted that there are more than 750,000 still to be found. Among the bizarre creatures to be dragged up so far are giant sea spiders the size of dinner plates and a blind lobster whose name means “terrible claw”.
Scientists recently predicted that there could even be sea monsters lurking beneath the waves, with as many as 18 unknown species larger than six feet in length. The recent discovery of a squid that measures more than 13 feet long shows what could still be found.
Closer to home, when the Natural History Museum in 2009 moved some of its 20 million-strong collection of insects and plants to another facility, curators discovered several new species of beetle. Max Barclay, curator of the Beetle Collection, says: “We are still finding new species among the specimens that were collected by Charles Darwin on the Beagle.”
Mark Wright, scientific adviser for WWF, adds: “Despite all the effort that has gone into looking for new species in the past 250 years, the world is still full of wonder and discovery waiting to be found.”
With such an overwhelming task ahead of them, the challenge for scientists is to discover new species before they die out.