Tarantulas ( theraphosidae ) are found throughout the world, inhabiting every continent except Antarctica. However, scientists did not know how they have become so widespread, since the females rarely leave their burrows and the males only travel when looking for a mate to reproduce. In addition, spiders tend to stay close to where they are born, as they do not usually make long trips.
Investigation Development
To answer this question, an international team of researchers looked for the origins of the tarantula group more than 100 million years ago, building a family tree. Once they created the family tree, they assigned a time axis to the spider fossils, thus estimating how and where the first tarantulas appeared and dispersed. Likewise, the results of the study were published in the journal PeerJ.
Scientists discovered that tarantulas first appeared during the Cretaceous period (in what is now America). But back then, America was part of the massive supercontinent Gondwana. The ancient tarantula relatives probably spread across the supercontinent, dispersing from America to Africa, Australia, and India. However, when Gondwana began to fragment, India broke away from Madagascar and collided with Asia, so spiders moved to that territory as well.
On the other hand, because tarantula fossils are so rare, the researchers had to collect data from mygalomorphs, a group of arachnids that includes tarantulas and other large, ground-dwelling spiders. Thus, after building the tree from all this information, the scientists adjusted the time using the fossil data.
Timeline of tarantulas
According to the chronological axis prepared by the team of researchers, tarantulas first appeared 120 million years ago in America. In Africa, however, they appeared 112 million years ago, while in India they settled 108 million years ago.
Thus, India separated from Madagascar approximately 95 to 84 million years ago. That division brought tarantulas to the Asian continent. However, before that happened, the tarantulas of India were divided into two groups with different lifestyles: one group of tarantulas that lived mostly in trees and the other that preferred life in burrows. And, although both groups reached Asia, the arboreal tarantulas did so around 20 million years later.
