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Hunting New Species: 4 new dwarf chameleons discovered in Madagascar
Copyright 2012 – Kris Heeter, Ph.D.
Four new dwarf chameleon species have recently been discovered in the northern Madagascar rainforests. The tiny reptiles, some of the smallest in the world, are only about an inch long and belong to the genus Brookesia.
Three genera of chameleons are found on the island of Madagascar: Brookesia, Calumma, and Furcifer.
The island harbors nearly 80 of the world’s estimated 185 chameleon species. The Brookesia species tend to live within a very small geographical radius.
The four new species have been named:
- Brookesia tristis
- Brookesia confidens
- Brookesia micra
- Brookesia desperata
Hunting the dwarf
Miniature species - - island dwarfism
Scientists have noted miniaturization of species like this is common in island populations, particularly on islands like Madagascar.
Miniature species often go undetected for obvious reasons - they are tiny and can easily hide.
Although difficult to find, dwarf organisms that represent extremes in nature can provide general insights into environmental constraints.
In the case of the dwarf chameleons found on Madagascar, the phenomenon is commonly known as "island dwarfism”.
Species isolated on an island are thought to experience limited resources and may have pressure to reproduce faster.
Faster reproduction and environmental constraints such as limited resources may lead to morphological and genetic changes that allow the species to evolve and survive. The evolution to smaller body types could lead to a reduced energy (food) need and the ability to hide easier from predators.
How they were discovered
These four new species were discovered by a team led by Dr. Frank Glaw, a staff scientist and head of the herpetology group at Zoologische Staatssammlung München.
Tools of the trade include headlamps, hiking gear, the desire to hike through the rainforest at the night during the rainy season, and after collection, the ability to do DNA analysis.
Chameleons roost in the vegetation or leaf litter and are easiest to collect at night.
Once collected, researchers used morphological traits and genetic analysis to determine whether the chameleons found belong to a previously identified species or not.
The sequencing of the mitochonrial 16S rRNA gene is standard for comparative analyses of species.
Comparing established genetic profiles of known chameleon species with those newly found specimens allows researchers to calculate the genetic divergence and determine whether the new species have enough genetic change in their DNA to constitute a new species.
More on dwarf chameleons
There are many species of dwarf chameleons. Often referred to a "leaf chameleons" or "pygmy chameleons", these little guys have become popular pets.
Chameleons are famous for their ability to change color in order to adapt and blend into their environment. They have parrot-like zygodactylous feet. Their eyes are separately mobile and stereoscopic. Many have a prehensile tail and horns on their odd shaped heads.
They are not isolated to just Madagascar. Another dwarf genus Bradypodion (meaning "slow-footed") is native to southern part of Africa.
Species (both dwarf and normal size) can be found in Africa, Asia, Sri Lanka, Spain, and Portugal. They have also been introduced to parts of the U.S.
Hunting new species
In general, new species are being discovered each year by zoologists, marine biologists, entomologists, ecologists, and microbiologists. Just this past year alone, just a short 42-day research expedition to the Luzon Island in the Philippines uncovered 300-500 new species!
To learn more, see: New Species Discovery: a 42-day journey
There is an institute in the United States dedicated to tracking these new worldwide discoveries.
The International Institute for Species Exploration, located at Arizona State University, compiles a list of species that are identified. It typically can take a few years to compile just one year’s worth of discoveries.
The team of scientists at the Institute follows the international literature for evidence of newly named species and compiles that data. They just recently finished compiling the data for 2009 and released a report of their findings.
How many species and what type of species are discovered in a year’s time?
I leave that as a cliff hanger and you can find the answer by going the related article below (just click on the title):
Glaw et al. 2012. Rivaling the world's smallest reptiles: Discovery of miniaturized and microendemic new species of leaf chameleons (Brookesia) from northern Madagascar.- PLoS ONE 7 (2): e31314