Arboreal tarantulas are known from a few tropical places in Asia, Africa, South and Central America and the Caribbean. These tarantulas generally have a lighter build, thinner bodies and longer legs, better suited for their habitat. They have increased surface area at the ends of their legs, allowing them to better climb different surfaces, while their light build makes them more agile.
Their core area is the Amazon, from where most of the species are known and normally very common, living in the jungle or even in house's surroundings. Now, nine new species were described from Central and Eastern Brazil, including four of the smallest arboreal species ever recorded.
The study was performed by Dr Rogério Bertani, who is a tarantula specialist and a researcher at the Instituto Butantan in Sao Paulo, Brazil. His results have been published in the open access journal ZooKeys.
"Instead of the seven species formerly known in the region, we now have sixteen", said Dr Bertani. "In a resurrected genus with a mysterious single species known from 1841, we have now five species". "These are the smallest arboreal tarantulas in the world, and their analysis suggests the genus to be very old, so they can be considered relicts of a formerly more widely distributed taxon".
Other discoveries include new species of tarantulas living inside bromeliads. "Only a single species had been known to live exclusively inside these plants, and now we have another that specialized in bromeliads as well". A further species was found at the top of table mountains where trees are rare. "This species also inhabits bromeliads, one of the few places for an arboreal tarantula to live that offer water and a retreat against the intense sunlight" he says.
The discovery of all these new species outside the Amazon was unexpected and illustrates how little we know of the fauna surrounding us, even from hot spots of threatened biodiversity like the Brazilian Atlantic Rainforest and the Cerrado (a kind of savannah vegetation). These species are highly endemic and the regions where they live are suffering high pressure from human activities. Therefore, studies for their conservation are necessaries. Furthermore, all these new species are colorful, which could attract the interest for capturing them for the pet trade, constituting another threat.