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In 2008, Windsor Aguirre and a team of biology students snagged a large piece of the evolutionary puzzle. Today, Professor Aguirre鈥檚 specimens shed new light on the evolutionary history of freshwater fishes. His research gives students a greater perspective on biology and the world around them.

In April 2012, a new species of suckermouth armored catfish was announced in National Geographic鈥攁 discovery made by Windsor Aguirre, assistant professor, Department of Biological Sciences.

As a field researcher, Aguirre explores how fish species work in nature, how they differ based on ecological preferences, and how they鈥檝e evolved.

鈥淚鈥檓 asking pretty fundamental questions,鈥� he says. 鈥淲hat factors facilitate or constrain the origin of a species? How do species actually form?鈥�

In Alaska, he鈥檚 studying the evolutionary diversification of three-spined stickleback fish. In South America, he鈥檚 tracing the evolutionary history of the common tetras by using molecular markers to create a phylogeny (a diagram based on patterns of differences in DNA sequences).

Discovering new species

On a trip to Ecuador in 2008, while collecting specimen in the Santa Rosa River, Aguirre pulled in a few fish he couldn鈥檛 readily identify.听

鈥淚 sent photos to Jon Armbruster, a taxonomist at Auburn University, who eventually determined that we were dealing with a new species, which he named Cordylancistrus santarosensis. Finding a new species was certainly exciting, but in some ways not that surprising: this region of the world is so little explored that scientists don鈥檛 know how many species of fresh water fish exist or how they鈥檙e distributed. We don鈥檛 even know which species of fish occur in which rivers.鈥�

This particular discovery turned out to be important for a few reasons. First, the species might be a 鈥渕issing link,鈥� as the 2.8-inch-long fish lacks armored plates on the sides of its head, which suggests it might connect the species Cordylancistrus (plated) and the genus Chaetostoma (not plated).

鈥淚鈥檓 not a catfish specialist,鈥� Aguirre explains, 鈥渂ut the new species is important biogeographically. It鈥檚 in a genus that wasn鈥檛 known to be in this region and it鈥檚 an intermediate between two genera; in theory, this specimen provides a little more information about the evolution of suckermouth catfish. Now, specialists have a new piece of a puzzle, and that鈥檚 always interesting.鈥�

The new species is yet more evidence of just how much in nature is still unknown.

鈥淔or some species, a huge amount of research has been done, so it鈥檚 tempting when one sees a model species鈥攕ay, for example, zebra fish鈥攖o think 鈥榳e must know this much about every species.鈥� But that鈥檚 not true,鈥� Aguirre says.听

鈥淣ew species are discovered every year. A sample is collected, someone describes it, it鈥檚 put in a museum, and that鈥檚 all we know. For most species, we know nothing more than their names. We don鈥檛 know what they eat, or how much variability is in their population, or where they fit in the evolutionary tree of life. Getting this information is really, really hard work.鈥�

In developing countries, there鈥檚 an urgency to find and describe species before they disappear.

鈥淭he areas with the greatest biodiversity often also have great poverty,鈥� says Aguirre. 鈥淎s countries exploit their natural resources, the loss of environment leads to the extinction of animal populations. We鈥檙e losing species before we even know they exist.鈥�

鈥淭hat鈥檚 why I say it鈥檚 the best and worst time to be a biologist: we鈥檝e never had as much information and scientific tools as we do now, but we鈥檙e losing habitats and species at unprecedented rates. The challenge is to conserve as much of the Earth鈥檚 biodiversity as possible, while still allowing governments in developing countries to do what鈥檚 necessary to combat poverty.鈥�

Why Study Fish?

鈥淚f you鈥檙e interested in questions related to evolution, fish are a great group to study,鈥� Aguirre recently told DePaul Newsline. 鈥淭here are more types of fish than there are types of mammals, amphibians, reptiles, and birds combined.鈥�

鈥淚t鈥檚 also a question of ease. The species I tend to work with are small, so it鈥檚 easier logistically than if you鈥檙e studying elephants.鈥� 鈻�