Re: NANFA-- Hybrid Fundulus?

Bruce Stallsmith (
Mon, 02 Dec 2002 20:07:23 -0500

I think you have a hot one on your hands. Sciadicus is usually described as
in the subgenus xenisma, you're right, compared to rubrifrons being in
zygonectes. The Fundulus hybrids I've heard of are notatus/olivaceus,
diaphanus/heteroclitus and catenatus/stellifer. If your two species have the
same number of chromosomes, I wouldn't be at all surprised that they could
hybridize. How many people have ever kept these two species together? You're
probably running an experiment... One piece of evidence whether it's a
hybrid or just a weird individual would be DNA tests, but those are kinda
tough for most people. You could also try to cross it with one or both of
the species in question. He might even be sterile, which would also be a
good sign of hybrid status.

--Bruce Stallsmith
Huntsville, AL, US of A

>From: "R. W. Wolff" <>
>To: <>
>Subject: NANFA-- Hybrid Fundulus?
>Date: Mon, 2 Dec 2002 18:17:32 -0600
>I have a developing killifish that ain't right.
>In my killi pond ( 9 feet by fifteen feet and about 30 inches deep) I keep
>several killis and a few other odds and ends during the warm months ( which
>this year was not very long ). When I harvested this fall what I thought
>was a small F. sciadicus ( plains topminnow) looked sort of strange. It was
>much more stout. I also had what I am pretty sure are F. rubrifrons (
>Redfaced topminnow) since they look different from cingulatus I have from a
>location that only has cingulatus, where as this fish came from the overlap
>of the two. I only had a couple young retrieved from these. Both species
>spawn in the same manner, use the same displays, and the males will display
>to each others females. The females always seemed to be able to know who to
>follow to the weed clumps after the display, as long as I was watching them
>anyways. The display consists of fighting another male, fins and gills
>flared, and the color turned up to 10. Then the male that wins this open
>water match will stay there and fling droplets of water across the surface.
>This is much the same thing many topminnows do when scared to divert
>attention from themselves. Anyways, the odd looking one is now developing
>colors consistent with being in between these two fish. Old literature I
>have say sciadicus is in subgenus zygonectes ( spelling?) along with the
>rubrifrons and others. Newer stuff I read puts sciadicus in xenisima (
>spelling?) the studfish subgenus. I would say how they act would make them
>more like the rubrifrons and chrysotus than caetnatus or stellifer. But
>do look sort of like a studfish up close, but then again they look like a
>topminnow as well.
>Has anyone heard of the freshwater Fundulus hybridizing? (I have read of
>diaphanus diaphanus hybrids with heteroclitus.) These two species do not
>occur together in nature. Both have reddish fins trimed in black, and a
>stripe in front of the dorsal fin. They are kind of hard to tell apart from
>a distance. Females are really close, with sciadicus more streamlined and a
>longer snout, and rubrifrons females have a gold iridesence on the cheek. I
>will continue to watch him as he grows and see what he looks like at a more
>mature size. Right now he is only just over an inch, but fully colored in
>comparison to a sciadicus, and nearly compared to the rubrifrons.
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