Genetic Analysis Finds Second Species of Giant Tortoise

Genetic Analysis Finds Second Species of Giant Tortoise

Definition of new species will lead to newly focused conservation efforts.

Scientists for years have observed two groups of tortoises on Santa Cruz Island in the Galapagos Archipelago, but through genetic analysis, have decided they are two separate species, according to a report on

The two groups lived on different parts of the island, one on the west side in an area known as the “Reserve” and the other on the east side close to a hill named “Cerro Fatal.”  Until now, scientists thought they were the same species.

A genetic analysis done by an international group led by Dr. Gisella Caccone at Yale University, has determined they are separate species.  The original species is named the Western Santa Cruz Tortoise, while the new species was dubbed Eastern Santa Cruz Tortoise.

The newly-discovered species is not near as well populated at the Western species, with the Eastern species numbering a few hundred, compared to a few thousand of the Western species.  Now researchers want to look more closely at the Eastern Tortoise, since it is a distinct species and not a part of a larger population of the Western species.

The new Eastern Santa Cruz Tortoise (Chelonoidis donfaustoi) was named for the primary caretaker at the Tortoise Breeding and Rearing Center on Santa Cruz, Don Fausto.  Fausto spent 43 years from 1971 to 2014 as a park ranger for the Galapagos National Park Directorate, and is responsible for the restoration of several tortoise species in the area.

Dr. Linda Cayot, Science Advisor for Galapagos Conservancy said, “This is an exciting moment in the history of Galapagos giant tortoises.  Over the last several years, the ever-growing role of genetics in guiding development of conservation strategies for Galapagos tortoises continually requires us to think in new ways.”

The Giant Tortoise Restoration Initiative is a joint effort of several groups to attempt to restore the Galapagos tortoise back to historical numbers.  The populations of giant tortoises were greatly reduced by human exploitation, introduction of harmful species and habitat degrading over the last few centuries.

The scientists will be taking a closer look at the Eastern Santa Cruz Tortoise’s nesting zones and potential threats to determine the best way to increase the count and protect the species.

Dr. Caccone adds, “Its low numbers, limited geographic range, and reduced genetic diversity make it vulnerable. As a newly recognized species, it will now receive the attention needed to ensure its survival.”




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