Florida biologists this week announced they have confirmed a new species of black bass, one that so closely resembles a cousin that it was nearly impossible to identify before DNA testing emerged.

And fishermen in South Mississippi and Southeast Louisiana may have already caught one, and will never know it.

The Choctaw bass (Micropterushaiaka) has been identified in river systems in the Florida panhandle and South Alabama, and is thought to likely inhabit streams in other coastal states. Included in the suspected range are the Pascagoula River system in south Mississippi and the Pearl River system that forms the border of Mississippi and Louisiana.

Long considered to be the spotted bass (Micropteruspunctulatus), first clear evidence of the Choctaw bass was found in 2007 by the Florida Fish and Wildlife Institute, the research division of the Florida Fish and Wildlife Conservation Commission.

According to a news release posted Tuesday (May 7) on the Florida wildlife agency's website, the find came during a test of fish from the Chipola River in Northwest Florida. FWRI scientists encountered a DNA profile that did not belong to any known bass species. To locate its source, they began testing archived bass tissues collected from nearby rivers.

By early 2009, scientists had discovered the same genetic profile in bass populations inhabiting the Choctawhatchee, Yellow, Blackwater, Escambia, Conecuh and Perdido rivers.

"We didn't set out to find a new species," said Mike Tringali, who heads the FWRI's genetics laboratory. "It found us."

After reinterpreting work done in 1940 by taxonomists Carl Hubbs and Reeve Bailey, scientists believe Choctaw bass could also occur in extreme Southwest Alabama and Southeast Mississippi. Since 2012, they have been working to confirm this.

A map on the Florida website shows the confirmed range to be on the western side of the Florida panhandle and South Central Alabama. The suspected range includes South Mississippi and a small area of Southeast Louisiana.

The scientific criteria for recognizing a new species are rigorous. Fortunately, the evidence assembled by the FWRI research team leaves no doubt that fish with this new genetic profile constitute a valid species.

Evidence has been submitted to the American Fisheries Society, which must approve the find and its name for it to be official.

Choctaw bass can usually be distinguished from other bass by counting scales, fin rays and gill rakers, which are comb-like projections inside the gills that prevent particles from collecting on the gill filaments. Foolproof identification, however, requires genetic testing.

The chosen names reflect the regional connection to the Choctaw Indian tribe, with the scientific term "haiaka" coming from the Choctaw word for "revealed."

FWRI say the biggest conservation threat to the Choctaw bass may come from its cousins, the spotted bass and Alabama bass, the latter a separate spotted bass species found in the upper Mobile River basin.

Typically, Choctaw bass have been found in the upper reaches of rivers and streams where sediment accumulates, avoiding stream headwaters and tidal zones found closer to the coast. As of late 2012, everywhere Choctaw bass had been collected, spotted bass and Alabama bass were absent.

It is feared that a natural expansion or intentional stocking of spotted bass in new waters could lead to displacing native species or a crossbreed.