"The Suwannee River turtle is way different from the others; it's been isolated as an independent species into the deep past," Roman says.
The molecular revolution that began in the 1980s has used DNA to redraw many boundaries between species. But to be fully confident in the genetic evidence they had gathered, the scientists also examined the turtles for differences in body shape and size. Close studies of the skulls and shells of museum specimens confirmed that "each of the three genetically distinct Macrochelys lineages can be diagnosed morphologically," the team writes in their new paper. In other words, experts can look at the turtles, particularly the back edge of the shell, and tell the species apart.
Until early in the 20th century, alligator snapping turtles were plentiful from headwaters in the Midwest into swamps of the Deep South, but "river turtles were hit hard in the 1960s and 1970s," Roman says. Hunters, often smalltime operators, "could clean out a stretch of the river in a few weeks time by just setting traps and waiting," he says. Florida was the first state to shut down commercial trapping and eventually all other states followed the last one being Louisiana.
"Turtle soup was traditionally served to politicians at political dinners," Roman says, "so a senator in Louisiana fought against protecting them." Today, Roman sees bipartisan support for protecting the turtles against current threats like water pollution, illegal harvest and collection for the pet trade, and river drawdowns upstream. "These are the symbols of their rivers," he says, "and part of the cultural history of bayous and backwaters." But they're also deeply connected to the ecologica
|Contact: Joshua Brown|
University of Vermont