Re: NANFA-L-- Use of pharyngeal teeth in minnow identification

Bonnie McNeely (bnmcneely-in-sbcglobal.net)
Mon, 28 Aug 2006 06:39:44 -0700 (PDT)

Dan, I don't know about aquarists doing this with any regularity at all, since the specimen must be sacrificed to do it. However, professionals and students use this regularly. It is highly reliable so far as being a means of determining this particular aspect of morphology, once one is practices at it. Specimens in museum collectons very often have the pharyngeal arches removed in the id process, then placed back in the opercular cavity for storage. So, if you have specimens you can sacrifice, time, patience, desire -- go ahead.

For small specimens, it can be done best under magnification -- say a dissecting scope or macroscope -- a large lens mounted in a frame with illumination, these are often used for sorting invertebrate samples. A sharp pointed forceps with ridges on the points for gripping helps, too. Ichthyology lab manuals and some fish id books show illustrations with instructions for doing this. Good luck.

Dave McNeely

Dan Johnson <danjohns-in-io.com> wrote:
I'm curious if any of you actually use pharyngeal teeth counts for
minnow identification. The counts seem to be a very good attribute for
distinguishing species. I've tried several times with 2" minnows only
to end up with a pile of mush and not sure I've found anything. Today I
decided to try with some bigger fish. So I went out and caught a two
foot grass carp. I dissected it and was able to find the distinctive
pharyngeal teeth that species possesses. I was able to find four and
five teeth attached on the two sides, but only found one or two teeth of
the 2nd row on one side. And there were 2-3 loose teeth the origin of
which is uncertain. Too much slimy tissue all over the place and lots
of effort to clean things off so things can be seen. I put the arches
in a plastic bag and left outside to let the maggots clean things up a
bit and I'll have another look. Should I keep trying? Thanks in
advance.

--Dan
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