Underwatertimes.com News Service - March 2, 2011 18:03 EST

A biologist from the University of Toronto Scarborough (UTSC) has discovered a new kind of tropical freshwater stingray.

Nathan Lovejoy, an associate professor of ecology and evolutionary biology at UTSC, is co-author on a new study detailing the discovery of a new genus and two new species of stingrays found in the upper Amazon.

Lovejoy's 10 years of research with his collaborator, Marcelo Rodrigues de Carvalho of the University of Sao Paolo, confirmed the first new genus of stingrays from the Amazon region in more than two decades.

"It took a considerable amount of time to collect enough specimens to describe the species," says Lovejoy, who sometimes had to compete with international fish exporters for the bigger examples. "They are uncommon fishes and therefore difficult to obtain."

Their work in the Upper Amazon confirmed the new genus, Heliotrygon, and the two new species, Heliotrygon gomesi and Heliotrygon rosai. Both are known for their large size, pancake-like appearance, having a distinct pattern of lateral line canals on the ventral surface and a degenerate spine.

Most of Lovejoy and Carvalho's specimens came from the Rio Nanay River, near Iquitos, Peru. Their discovery brings the total number of Neotropical stingray genera to four. Before their study, the last new genus of stingrays of Amazon was described in 1987.

"The most important thing this discovery tells us is that there are quite likely to be other large fishes in the Amazon yet to be discovered and described," says Lovejoy. "Our understanding of the biodiversity of this region is not complete, by any stretch of the imagination."

Lovejoy's paper was recently published in the scientific journal Zootaxa.