11 kinds of chameleon found masquerading as a single species
Chameleons in Madagascar previously thought to all belong to a single species have actually turned out to be 11 separate ones.
Chameleons are famous for their ability to disguise themselves, adapting their hue through nanocrystals in their skin, actively tuning to reflect light differently. One of the most famous masters of this disguise is the panther chameleon, first described in 1829, and native only to Madagascar.
According to research published over the weekend in the journal Molecular Ecology, this chameleon has kept another trick in its skin. It's not a single species of chameleon. It's 11.
A team led by Professor Michel Milinkovitch of the University of Geneva, in collaboration with Professor Achille Raselimanana of the University of Antananarivo, wasn't looking for new species. Instead, the team was looking for genetic keys that might indicate how the panther chameleon achieves its extraordinarily broad colour palette.
They were basing the research on the notion that colour variations in panther chameleons seem to be based on location: some panther chameleons are a vivid blue, such as those from the island of Nosy Be, while others from different regions can be red, orange or green.
"It's always the same thing when you go to do science, you have an intuition that there may be something interesting, but you don't know what," Professor Milinkovitch told CNET's Crave blog. "I got interested because I am also doing a lot of genetics and I thought it was an interesting species in terms of geography."
The team members collected blood samples from 324 individual chameleons, during two expeditions of three weeks each. They also photographed the chameleons. They then sequenced the mitochondrial and nuclear DNA of each chameleon, analysing the data based on the hypothesis that colour and pattern variations are regional, comparing the blood samples against the photographs.
What the team found was that colour and patterning, as well as geography, corresponded with the genetic lineage of each chameleon's species, with very little interbreeding, if any. Using mathematical analysis, genetic lineage could be successfully gauged visually about 85 percent of the time. The result indicates that each location-specific population may need to be considered a discrete species.
"I wasn't expecting so much structure," Professor Milinkovitch said. "I wasn't expecting 11, that was a lot! I was expecting maybe three."
The next step will be for taxonomists to study and describe the animals according to classification guidelines, but there is still work for Professor Milinkovitch and his team -- determining the genetic basis for the colour variation.
"Genetic data that tell us about interbreeding and non-interbreeding; if an animal has more blue or more green, there is now a genetic basis for it," he said. I would like to understand the genetic determinism for these colour variations. Do the colours have regional adaptive values?"
The research also means that conservation approaches to the animals may need to be reconsidered, with each species managed separately.
"When you manage biodiversity, really there is a lot of management because forests are being destroyed at a really high rate in Madagascar. Chameleons are distributed across all of the north Madagascar, and if that's a single species, you manage that in a specific way," Professor Milinkovitch explained.
"If a portion of the forest is destroyed, you might say, that's all right, because it's all one species. Eleven species are handled very differently, because they are geographically restricted, if you destroy a patch of forest, you might destroy a species."
The island of Madagascar is one of the most biodiverse regions on the planet, but it is also under threat from human activity. Deforestation and logging destroy the habitats of many species, driving them to extinction. The team hopes that this discovery will help raise awareness of the conservation efforts in the region and save the lives of animals there.
Edit May 28, 2015, 8.44am AEST: Added Professor Milinkovitch's comments.