Rosyface vs Tennessee Shiner

Does anyone have a reliable way of separating Notropis rubellus from Notropis leuciodus without killing (or stressing) them? I am looking at specimens from Copper Creek, Virginia, Clinch/Tennessee River drainage.

Thanks!

Rubellus: 9-11 (usually 10)anal rays, dorsal origin distinctly posterior to pelvic origin, faint or no gold stripe above dark lateral stripe.
Leuciodus: 7-9 (usually 8 ) anal rays, dorsal origin directly above or barely posterior to pelvic origin, distinct gold stripe above dark lateral stripe.
A back-lit photo may work for counting anal rays. The Tennessee basin "rubellus" are now "micropteryx". The Ohio/New R are the true rubellus.... and dont forget to consider N.photogenis too.

Does anyone have a reliable way of separating Notropis rubellus from Notropis leuciodus without killing (or stressing) them? I am looking at specimens from Copper Creek, Virginia, Clinch/Tennessee River drainage.

Thanks!

Edited by gerald, 31 May 2011 - 09:42 AM.

Do they have a dark caudal spot? Is the lateral line HEAVILY stitched? Where is the dorsal fin origin in relation to the pelciv fin origin?

Rubellus: 9-11 (usually 10)anal rays, dorsal origin distinctly posterior to pelvic origin, faint or no gold stripe above dark lateral stripe.
Leuciodus: 7-9 (usually 8 ) anal rays, dorsal origin directly above or barely posterior to pelvic origin, distinct gold stripe above dark lateral stripe.
A back-lit photo may work for counting anal rays. The Tennessee basin "rubellus" are now "micropteryx". The Ohio/New R are the true rubellus.... and dont forget to consider N.photogenis too.

That sounds do-able. Thanks, Gerald! Still pretty subtle, though. The NANFA Forum: Where the experts hang out!

I think I can pick out photogenis pretty well. So micropteryx is now a described species? Can you give me a citation to look up? Thanks!

Do they have a dark caudal spot? Is the lateral line HEAVILY stitched? Where is the dorsal fin origin in relation to the pelciv fin origin?

Oh, yeah, I guess rubellus doesn't really have the caudal spot, huh? Stitching too, that's good. I was going to go on fin origins, but Freshwater Fishes of Virginia seemed to indicate that this was quite variable and maybe not reliable. Thanks, Matt! Experts indeed!

slightly off topic but what is the external difference between micropteryx and rubellus? Any breeding color difference?

Edited by tricolor, 31 May 2011 - 03:45 PM.