Tarantula’s Ubiquity Traced Back to the Cretaceous

Carnegie Mellon University - April 21, 2021 Tarantulas are among the most notorious spiders, due in part to their size and vibrant colors. With their prevalence throughout the world, it may be surprising to learn that tarantulas are actually homebodies. Females and their young rarely leave their burrows and only mature males will wander to seek out a mate. An international team of researchers, including Carnegie Mellon University's Saoirse Foley , set out on an ancestry.com-like investigation to discover how this sedentary spider came to inhabit six out of seven continents. They looked to the transcriptomes, the sum of all the transcripts from the mRNA, of many tarantulas and other spiders from different time periods. Their findings were published online by PeerJ on April 6. They used the transcriptomes to build a genetic tree of spiders and then time-calibrated their tree with fossil data.