Tiny lizards found in Madagascar
18 Feb BBC
One of the world’s tiniest lizards has been discovered by keen-eyed
researchers in Madagascar.
The miniature chameleon, Brookesia micra, reaches a maximum length of
just 29mm.
German scientists also found a further three new species in the north
of the island.
The lizards were limited to very small ranges and scientists are
concerned they could be at risk from habitat disturbance. The discovery
is reported in the journal PLoS ONE. The research team, led by Dr Frank
Glaw from the Zoologische Staatssammlung in Munich, have a specialist
knowledge of Madagascar’s dwarf chameleons having described other
species in the past.
They conducted fieldwork at night during the wet season in order to
find the easily overlooked animals.
“They mostly live in the leaf litter in the day... But at night they
climb up and then you can spot them,” said Dr Glaw, explaining that the
animals moved up into branches to sleep.
The scientists carefully scanned the most likely habitats with
torches and headlamps to find roosting sites.
They found the smallest species on a remote limestone islet and
believe it may represent an extreme case of island dwarfism.
This phenomenon occurs when a species becomes smaller over
evolutionary time in order to adapt to a restricted habitat such as an
island.
According to Dr Glaw there could have been a “two-island effect” in
the case of B. micra.
“It is possible that the big island of Madagascar has produced the
general group of dwarf chameleons and the very small island has produced
the tiny species,” he told BBC Nature.
Varied but vulnerable
Because the chameleons looked similar in appearance, researchers
conducted a genetic analysis to confirm that they were indeed four
distinct species.
The genetic differences between the species were described as
“remarkable” by team member Miguel Vences from the Technical University
of Braunschweig, Germany.
“This indicates that they separated from each other millions of years
ago - even earlier than many other chameleon species,” he said.
Each of the new species was restricted to a very small territory,
just a single square kilometre for the smallest.
“In Madagascar many species are restricted to small habitats and that
makes it important to conserve them” said Dr Glaw.
Scientists believe the small ranges of the species make them
especially sensitive to habitat disturbance.
B. tristis, named after the French word “triste” meaning sad, was
found in an isolated patch of forest close to an expanding city.
The team chose thought-provoking names as an expression of their
concern for the future of the island’s micro-endemic species. |