February 7, 2011
Carole Baldwin, curator of fishes at the National Museum of Natural History, thought that scientists had revealed just about all there was to be known about Starksia blennies. After all, the small (less than two inches) shallow-reef fish found in the western Atlantic and eastern Pacific Oceans had been studied for well over 100 years. But when Baldwin and her colleagues were working to identify the species of some young Starksia larvae they had collected, by matching its DNA to DNA barcodes of Starksia adults, they found some discrepancies.
“These things that we thought were one species came out very different genetically,” says Baldwin. With further investigation, she and her research team discovered that what were thought to be three species—Starksia atlantica, Starksia lepicoelia and Starksia sluiteri—are actually ten. ”It’s like there were species hiding within other species, and it took the DNA combined with traditional techniques [of looking at the morphology of the fish] to reveal them,” she says.
Typically, new species are named after geography (i.e. Starksia atlantica, found in the Atlantic Ocean), their distinguishing anatomical features or people. Baldwin’s team named the seven new species after influential colleagues (six of the seven of whom are employed by the Smithsonian Institution). “We put a lot of effort into this work, and we wanted to honor some of the people that were instrumental in our getting the work done,” says Baldwin. S. springeri, for instance, was named after Victor Springer, senior scientist emeritus at the National Museum of Natural History, and S. williamsi, after Jeffrey Williams, the museum’s collections manager—both of whom have studied blennies.
Mary Sangrey, who coordinates the intern program at NMNH and connected Baldwin with Cristina Castillo, one of the study’s co-authors, was the namesake for S. sangreyae. Lee Weigt, the head of the Smithsonian’s Laboratories of Analytical Biology who introduced Baldwin to DNA barcoding, was honored in the naming of S. weigti; D. Ross Robertson of the Smithsonian Tropical Research Institute, who collected specimens in Panama, in the naming of S. robertsoni; and Michael Lang, director of the Smithsonian Marine Science Network and the Smithsonian Diving Program, in the naming of S. langi. S. greenfieldi is in honor of David Greenfield, not of the Smithsonian, but who studied the genus Starksia extensively. All seven species, which differ primarily in their pigmentation, are described in a study, published on February 3, in the scientific journal ZooKeys.
Baldwin’s team has amassed a database containing the DNA barcodes of more than 6,000 Caribbean fish specimens. “We are sitting on a gold mine of DNA sequences that can be used to address a lot of different kinds of questions about evolution and speciation of Caribbean fishes,” she says.
Could they have done what they did without DNA? “The answer is yes,” says Baldwin,”but it would have taken a heck of a long time. How would we have even known to look at the Starksia blennies to begin with? Part of the beauty of the DNA is that it points you to where the potential new species are.”
The discovery of seven new species in a well-studied geographic region and genus makes you wonder just how many other species are yet to be described—in coral reefs and other ecosystems. Baldwin’s next step is to explore reefs deeper than 150 feet. ”We really are in a new age of biological discovery,” she says.
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