'I took photos and showed them to a local herpetologist, who instantly recognised that it was a new species.'

The creature, small enough to sit in the palm of a hand, was named today as Kinyongia magomberae by scientists writing in the African Journal of Herpetology.

Shortly after the first discovery, a second Kinyongia chameleon was found by one of Dr Marshall's colleagues about seven miles away. Unlike the first specimen, this one was very much alive.

'It's amazing and wonderful to find a new species like this,' said Dr Marshall, from the University of York's Environment Department.

'I've been working in Tanzania for around 11 years now and have identified a couple of new tree species, but to find a vertebrate is pretty special.

'Obviously chameleons are very well camouflaged. You walk through the forest and tend not to see them.'

On average two new species of chameleons are discovered in the world each year.

Dr Marshall said he hoped the new find would assist efforts to protect the Magombera forest. Naming the creature after the forest would help to win the support and co-operation of local people, he said.

Due to an administrative mistake, the forest, also home to the endangered red colobus monkey, had no protected status. Half of it was owned by a sugar company that had intended to clear the land to make way for settlements, but was now reconsidering its plans.

'Hopefully this discovery will support efforts to provide this area and others like it with greater protection,' said Dr Marshall, who is director of conservation science at the Flamingo Land theme park and zoo in Malton, North Yorkshire.