How many species?

Finding species boundaries in Antarctic fishes

I wrote a piece for the Charlotte Observer about our recent study investigating species boundaries in a very unusual group of Antarctic fishes. This is a collaborative effort between our unit, the University of Galveston in Texas, Museum of New Zealand Te Papa Tongarewa, NOAA’s Antarctic ecosystem research division and Yale University. I wanted to repost the article and also link anyone interested to the study here

The Story

How many species are there? This simple question has eluded a concrete answer since Carolus Linnaeus created the species classification system almost 300 years ago. For centuries, intrepid individuals have braved some of the world’s most remote and hostile environments, bringing back detailed descriptions and specimens of never before seen organisms. This enterprise was not without risk, and many of these adventurous individuals never returned. Despite the risk and uncertain prospects of success, these seekers of species collectively described tens of thousands of organisms, greatly advancing our knowledge of the natural world.

Yet, even with these centuries of effort, it may be a surprise to hear that one of the biggest conservation challenges in the 21st century continues to be figuring out just how many species we share our planet with. The last several hundred years have yielded no slow down of scientists making headlines through the exciting discovery of a new species. If anything, the pace of species discovery is continually increasing.

There are several reasons for the rapid pace of species discovery. For example, technological advances and international collaborations are providing access to previously inaccessible regions. In addition, the use of DNA allows researchers to finally view species boundaries from the point of view of the organisms they are studying.

How does DNA let us delimit species in a new way? The answer is in the genes. When we look at a group of individual plants or animals, they may look similar enough to us for us to consider them the same species. However, these organisms may be as likely to interbreed with each other as we are with say, chimpanzees. Not very. This lack of gene sharing between populations gives us the molecular signature of where species boundaries are in nature.

Recently, I led a team of researchers from Yale University, NOAA, Texas A & M University at Galveston, and the Museum of New Zealand Te Papa Tongarewa, in an investigation of exactly where species boundaries are across the range of group of Antarctic icefishes called “Cryodraco”. For over a hundred years, species boundaries in this group have been unclear. Our study provides strong, DNA-based, evidence that there is in fact more than one species of Cryodraco.

Why does this matter?

In the case of Cryodraco, we’re contributing to the efforts of polar scientists racing to describe the biodiversity of Antarctica. Understanding how species diversity originates and is naturally maintained is critical for forecasting how changes in climate or currents will impact this unique ecosystem in the future. More broadly, the efforts of scientists to delimit “species” forms the foundation for studies across all biological disciplines including studies of great economic and medical importance.

Our study sheds some light on how species are generated in Antarctica, but it is important to realize that new species are not just being found in far away environments. In the last year both a new species of leaf-hopper and frog were found practically in the shadow of the New Jersey Turnpike. Indeed, our quest to document all of earth’s species is far from over.

Interested in learning more? The full-length scientific article can be accessed here

The original piece in the Charlotte Observer is here

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