An international team of scientists has discovered there are actually two species of giant tortoises living on Santa Cruz Island in the centre of the Galápagos Archipelago. Until now, it was assumed that the two giant tortoise populations on the island were of the same species, just living on different sides of the island.
However, genetic analysis, conducted by an international group led by Yale University’s Adalgisa Caccone, and including UBC Okanagan associate professor Michael Russello, has clearly identified two separate populations.
The new species, only found on the eastern side of Santa Cruz Island and occupying an area currently estimated at about 40 sq km (one/10th of the island’s size) has been called the Eastern Santa Cruz Tortoise (Chelonoidis donfaustoi).
While the Western Santa Cruz Tortoise has a few thousand individuals, the newly named Eastern Santa Cruz Tortoise numbers are in the low hundreds. Its distribution, nesting zones, abundance and potential threats are not well known.
Over the centuries, giant tortoises were devastated throughout the Galápagos Islands due to human exploitation, introduced species, and habitat degradation. The Giant Tortoise Restoration Initiative, a collaborative project of the Galápagos National Park Directorate, Galápagos Conservancy, and international scientists, is focused on the long-term restoration of all Galápagos tortoise populations to historical numbers.
Research team member Russello, who heads the Ecological and Conservation Genomics Laboratory at UBC’s Okanagan campus, first started working on this project when he was a postdoctoral fellow at Yale University.
“We initially reported cryptic species diversity in the giant Galápagos tortoises of Santa Cruz Island back in 2005,” he said. “It has been a privilege to work with this international team that now includes academics and in-country scientists and managers on four continents.
Russello says the research team will continue to explore patterns of variation in Galápagos tortoises and seek novel ways in which genetic and genomic tools can be used to preserve the tortoise population.