This spring I managed to make it to Missouri for my first sampling trip to the state. We came across what I've been calling Notropis nubilus but they seem to differ enough from Illinois fish to ask questions.


Above photo from the Big Piney in Missouri in April


Above photo from a Spring River trib in Missouri


Above photo from Jo Davies county Illinois


Above photo from Jo Davies county Illinois

When comparing the first two photos, they appear rather similar to me aside from nuptial color but more importantly posterior scale coloration. Perhaps scale coloration difference is a result of breeding color? Perhaps these are not the same fish?
When comparing the last two photos they appear nearly identical aside from nuptial coloration.
Comparing the first two photos against the last two photos, I see a significant difference in snout length and shape (Missouri fish have a longer and more rounded snout compared to "Illinois" fish). I also see the eye of the Missouri fish appears smaller that Illinois fish. Missouri fish seem to have less pigmentation around the lateral line.

I guess I'm curious if this is a correct ID (If not, this thread is in the wrong forum and I apologize) and if so, what information can folks share about these differences. Does anyone have N. nubilus photos to compare?
Sorry, I don't have any vouchers to reference, only these photos and thanks in advance.

Hey Uland,

Pete Berendzen and his students at the University of Northern Iowa have been plugging away at this problem. It's likely that there's several different critters involved, as there's deep genetic breaks between Upper Mississippi River, northern Ozark, and southern Ozark populations (duh, like almost every other fish "species" that occurs in the region). He'd probably be interested in fresh material from southern IL, as well as seeing your photos...

cheers,
Dave

Uland...
Your photos are exquisite and most excellent for side by side comparisons and specie identification. Honestly i can tell very little difference between the snout length, roundness nor eye size. Certainly in the single digits of percentage of eye diameter.
But man can one see the incredible detail and beauty of these creatures in your pictures.
It might be good to note the time of year along with the location. That possibly would aid in the breeding coloration anaylsis.
And tho i do favor a black background for graphic impact your choice of rustoleum grey is likely the best overall.
Excellent images.
I would have to call all 4 pictures / individuals are of the same species, unless someone can point out a obvious physical visual characteristic beyond coloration. I cant.

Casper

Casper, thanks for all the kind comments. I guess you're right, these differences are minor. My use of the word "significant" was inappropriate. You're also right about dates which I started to provide but failed to follow through.
#1 & 2 April
#3 March
#4 July
Like you Casper, I prefer black background but have found it too difficult to photo squirmy little fishes. In time, I might master the camera and fishes enough to use a black background.

Dave, you really hit the nail on the head in offering Peter Berendzen as a source for my query. I could not have timed my question any better to be honest. Thanks for the suggestion.

I remembered about a trip to Missouri in June many years ago I saw nubilis with bright yellow mouth and fin too.

Fish 3 is different in the following respects: snout length (also in fish 4), and posterior margin of the dorsal fin. Also the mouth is more terminal than the others, especially compared to 1 and 2.

I noticed the same thing in Mississippi "longnose" shiners - they are clearly different from Alabama longnose shiners. I was puzzled for a while but I decided to lump them in with N. longirostris, just so I would have something to call them.