In 2005, farmers in Antananarivo discovered an unfamiliar creature in their rice paddies. It was a crayfish unlike any other in Madagascar, and it soon spread throughout the country’s central highlands. When a team of researchers at the German Cancer Research Center in Heidelberg sequenced its genome a decade later, they confirmed that it was an entirely new species, and, remarkably, one that had evolved within the past 30 years. Somehow, a mutation in crayfish kept by aquarium breeders in Germany had produced all-female offspring that were clones of the mother, capable of reproducing without males. This rare ability occurs in roughly one out of every 1,000 vertebrate species; it’s even rarer for it to be the only way a species procreates, as is the case for marbled crayfish (Procambarus virginalis). Malagasy biologist Ranja Andriantsoa was part of that research team, which began studying the marbled crayfish as a way to learn about cancerous tumors. Like cancer cells, marbled crayfish are highly adaptable, they grow quickly, and each generation is genetically identical to the last. Ranja Andriantsoa near one of her study sites on the Andragnaroa River, where invasive marbled crayfish (Procambarus virginalis) are moving into habitat occupied by endemic crayfish (genus Astacoides). The forest beyond the river is Ranomafana National Park. Image courtesy of Ranja Andriantsoa. In Madagascar, the crayfish’s rapid spread drove fears that it would damage delicate aquatic ecosystems, even as locals came to rely on it as an abundant and affordable source of protein. Fifteen years…This article was originally published on Mongabay Läs mer