Cnemasspis Kolhapurensis is endemic to parts of India's Western Ghats
Scientists have discovered a new species of lizard in the lush Western Ghats mountain range in the Indian state of Maharashtra.
The small reptile is a form of gecko and was found by taxonomist Varad Giri in the Kolhapur district. It has been named Cnemasspis kolhapurensis.
Mr Giri and his co-workers published their findings in this month's edition of the Zootaxa journal.
It is the third new species of lizard recently discovered in the area.
Mr Giri, a curator at the Bombay Natural History Society, told the BBC that the Western Ghats has never been surveyed for amphibians and reptiles.
"A gecko of this particular character has not been recognised elsewhere in the world," he said.
Mr Giri said he first noticed the lizard in 2005 during a survey of one of the forests in the area.
"When I first stumbled across it, the lizard looked like a normal specimen," he said.
"It was basically a form of gecko but then I saw that it was interesting because its scales were shiny."
He said that when the gecko was held up in a certain light, the tail dorsum exhibited an "iridescent sheen".
Iridescence is commonly reported in a variety of reptiles - but not geckos.
Once Mr Giri and his co-workers had analysed the specimen, they realised it was a previously unknown species.
They then enlisted the help of Dr Aaron M Bauer, an expert on lizards based at Villanova University in the US, to confirm the discovery.
Cnemasspis kolhapurensis are mostly small in size and have a circular, rather than elliptical, pupil. They are generally found in forests although some have also been found in areas inhabited by humans.
Mr Giri said it is a ground-dwelling specimen and can be seen in leaf litter or under rocks.
"Presently this species is known only to this area. It is endemic to the northern parts of the Western Ghats," he added.
The Western Ghats mountain range is said to be one of the world's "biodiversity hotspots".
But analysts say that the area is at risk of a biodiversity crisis, because it has long been under threat from logging and human encroachment.
Mr Giri says the discovery may well help in arguments to preserve parts of the landscape.
"This is really important now because there is a lot of human interference and deforestation," he said.
Other new species of lizard previously discovered in the area were Hemidactlyus sataraensis and Hemidactylus aaronbaueri.
Saturday, July 25, 2009
Wednesday, July 22, 2009
Editor, Earth News
At least one in ten species of dragonfly and damselfly are threatened with extinction, according to the first world survey of their numbers.
The figure may be an underestimate as so little is known about many species.
However, the news is not all bad. The survey published in Biological Conservation is the first to assess the vulnerability of any insect group on a global scale.
And it suggests the extinction risk faced by insects has been exaggerated.
PROPORTION OF THREATENED SPECIES
31% of amphibians
20% of mammals
12% of birds
10% of dragonflies and damselflies
Viola Clausnitzer led an international team of conservation scientists from Germany, Australia, Japan, Russia and the UK among others. They reviewed the status of a random sample of 1500 of the 5680 dragonflies and damselflies known to science.
The team assessed the population and distribution of each species according to the Red List criteria set down by the World Conservation Union (IUCN).
They found that more than half of the species should be categorised as Least Concern, which means they likely remain widespread globally, or are not threatened even if they live in a restricted range.
But one in 10 species is threatened, meaning it is categorised as critically endangered, endangered or vulnerable.
The Pemba Featherleg (Platycnemis pembipes) a fragile damselfly first discovered in 2001. The species inhabits a single stream in Tanzania and is listed as Critically Endangered. (V. Clausnitzer)
"It's fair to say that is an underestimate," says Clausnitzer, as too little data exists to accurately assess the status of 35 per cent of the species.
Dragonflies and damselflies, which belong to the insect order known as the Odonata, are susceptible because the larvae of each species live in water. So pollution and changes to habitat, such as forest degradation, which affect water courses can have an impact.
Indeed, because of their sensitivity to water and habitat quality, dragonflies are frequently used to assess environmental health. With their striking colours and behaviour they can be used as indicator species. "If they disappear you've got something wrong with your habitat," says Clausnitzer.
Those species most at risk tend to live in south east Asia and Australia.
In south east Asia, a large number of species are endemic to islands such as the Philippines or within Indonesia, and cannot escape detrimental impacts on their habitat.
Two species of Odonata are known to have gone extinct
Both lived on islands
Sympetrum dilatatum once lived on Saint Helena
Megalagrion jugorum once lived on Maui in the Hawaiian islands
In Australia, climate change is having an especially strong impact on freshwater systems.
The survey is the first to assess the global health of any order of insects. Compared to vertebrates, the dragonflies and damselflies are not doing badly.
"Amphibians are more threatened than dragonflies in general," says Clausnitzer. Amphibians are being particularly afflicted by the deadly chytrid fungus. "Another difference is that adult dragonflies are more mobile. If one site is destroyed they still have the chance to fly to another site, which frogs don't have."
They also seem less to be less threatened than the mammals, but at a similar level of risk as birds.
"We were a bit surprised that the dragonflies are not that bad off," says Clausnitzer.
"There is a big discussion going on about invertebrates and extinction rates in insects, and this discussion is not based on any real figures. It is all estimations," she adds.
Only males of Klugi's Threadtail (Protoneura klugi) were known from two locations in Amazonian Peru. The species is listed as Data deficient. (R. W. Garrison)
In general, conservationists have feared that a much higher proportion of insect species face extinction.
However, Clausnitzer cautions that much more research needs to be done to be sure, and different groups of insects might face very different challenges.
For instance, while the reliance of dragonflies and damselflies on water makes them susceptible, says Clausnitzer "dragonflies are the strongest fliers in the insect kingdom. So you might get a very different picture if you take less capable fliers."
Wednesday, July 15, 2009
Thursday, July 9, 2009
Editor, Earth News
An adult C. mulmeinensis alongside decoy prey pellets (L) and decoy egg sacs (R)
There is a species of spider that builds models of itself, which it uses as decoys to distract predators.
The spider may be the first example of an animal building a life-size replica of its own body.
So believe the scientists who made the discovery, which is published in the journal Animal Behaviour.
The arachnid's behaviour also offers one explanation for why many spiders like to decorate their webs with strange-looking ornaments.
Many animals try to divert the attentions of predators by becoming masters of disguise.
Some try to avoid being seen altogether by using camouflage to blend in against a background, such as the peppered moth evolving motley wings that blend into tree bark, or stick insects that look like sticks.
Others evolve more conspicuous ornaments designed to distract a predator, such as butterflies that grow large eyespots or lizards that quickly move colourful tails, which they detach from their bodies if grabbed.
This latter strategy has puzzled biologists, because attracting predators in the first place is usually a bad idea.
One hypothesis is that animals which grow conspicuous ornaments benefit overall, because directing a predator to attack an expendable part of the body, such as the lizard's tail, outweighs the costs of attracting the attention of the predator in the first place.
But animals do not tend to actually build life-like replica models of themselves to act as decoys.
However, that is exactly what a species of orb spider called Cyclosa mulmeinensis does, biologists Ling Tseng and I-Min Tso of Tunghai University in Taichung, Taiwan, have discovered.
This and other related spiders in the same genus decorate their webs with material such as detritus, plant parts, prey remains or egg sacs.
Because such detritus is often of a similar colour to the spider, researchers suspected it might help camouflage the arachnid.
Our study seems to be the first to empirically demonstrate the function of animal-made decoys
Spider specialist I-Min Tso
Initially Tseng and Tso decided to test the idea by videoing another related species called Cyclosa confusa living in the wild. They measured how often predatory wasps attacked the spiders in webs decorated with detritus compared with those in undecorated webs.
"We predicted that spiders with prey carcass decorations on webs should receive fewer wasp attacks because spiders should be well camouflaged by such objects," says Tso. "To our surprise, spiders on decorated webs received far more attacks than those on undecorated webs."
That confirmed that the decorations attracted predators rather than acting as camouflage.
However, Tseng and Tso suspected that these decorations might also redirect enough attacks to make them worthwhile.
So they tested the idea on another species Cyclosa mulmeinensis living on Orchid Island off the southeast coast of Taiwan. This species decorates its web with both the remains of dead insect prey and egg sacs.
Intriguingly, the spiders made prey pellets and egg sacs that were the same size as its own body.
The researchers also found that these decorations appeared to wasps to be the same colour, and reflect light in the same way, as the spider's body.
In short, the spider made decorations that were of the same size, shape and appearance as itself.
"Our results show that this vulnerable spider protects itself from predator attacks by constructing decoys that increase the conspicuousness of the web, and resemble its own appearance in size and colour," the researchers write in Animal Behaviour.
A female C. mulmeinensis
"When both spiders and web decorations are present on the same web, they look like a string of nearly identical oval objects to the predators."
"I don't know of any animal that actively builds a decoy of itself. Our study seems to be the first to empirically demonstrate the function of animal-made decoys," says Tso.
The decoys worked, too. More often than not, a wasp would attack a decoy rather than the spider, thinking it to be a tasty meal.
But all wasp strikes on spiders living on undecorated webs were directed straight at the spider.
"Decorations built by Cyclosa spiders function as a conspicuous anti-predator device instead of a camouflaging device. The benefit of successful escape from predator attack seems to outweigh the cost of increased detection," says Tso.
Scientists have been trying to answer the question of why many species decorate their webs for more than 100 years.
Tso suspects that there is no single answer.
"I think that the functions of web decorations might be very diverse and differ from taxa to taxa. Different spiders seem to decorate their webs for different reasons," he says.
For example, spiders often decorate their webs with silk ornaments, which might strengthen the web, act as a warning signal to predators, to deter large animals from accidentally walking into the web, destroying it, or to act as a visual signal to attract prey.
Others, including Cyclosa species, may use non-silk decorations primarily as anti-predator devices.