An Extinct Creature Returns to Life
A clam thought to have died out 40,000 years ago has been discovered living. Researchers are still unsure of how the bivalve managed to elude discovery for so long. A species of clam has made a comeback.
Scientists believed that the Cymatioa cooki clam, which had only ever been discovered as a fossil, had been extinct for more than 40,000 years. Then, in 2018, marine ecologist Jeff Goddard discovered something strange while searching tide pools for sea slugs off the coast of California: a white, translucent bivalve that was about 11 millimeters long.
In order to compare the live specimen with other species known from the fossil record, the couple eventually managed to capture one in 2019. It was remarkably similar to a fossil bivalve that naturalist George Willett initially described in the 1930s.
Willett gave the species Edna Cook’s name in honor of the shell enthusiast who identified the fossil as being special among more than 30,000 other shells in her collection.
According to Valentich-Scott, “Once I physically saw that original specimen that Willett had used for his description, I knew right away” that the live clam was of the same species.
The experts are still baffled as to how the creatures managed to avoid discovery for so long. One theory is that C. cooki prefers a more secluded environment in Baja, California, further south. Some clam larvae may have been carried into Santa Barbara by a mass of warm water. The living clams have been located by Valentich-Scott and Goddard at least twice and maybe four times so far.
According to University of Chicago paleontologist David Jablonski, who was not involved in the study, “it’s rare to find something first as a fossil and then living.”
C. cooki’s triumphant resurgence, as described in ZooKeys on November 7th, adds the clam to a class of creatures known as the Lazarus taxa that appear to have come back from the dead. Modern scientists have access to a huge variety of animal specimens, but according to Jablonski, “there’s always more to find.”
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