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Pistolgrip, Tritogonia verrucosa
Description: The Pistolgrip is unique
and the photos show why. The shell is
quite thin at the extreme posterior end
which steadily increases in thickness
to the anterior end which is thick and
heavy. The shape is a study in
contrasts from the smoothly rounded
anterior end grading into the posterior
end with its remarkably large and
prominent posterior slope, terminating
in the extended "pistol-grip". The
surface is covered in large tubercles.
Similar species: There are no other
mussels in Nebraska that look like a
Pistolgrip.
Conservation status: G5, N4/N5, S1.
The Pistolgrip may still be present in
the Big Blue River but its continued
survival may be in doubt.
Hosts: Brown bullhead, flathead
catfish, yellow bullhead.
Habitats used: Medium to large
rivers in mud, sand or gravel
(Cummings and Mayer 1992). May
occur on any substrate, including sand
(Oesch 1995). Apparently adaptable
and can be found from 1 foot to 20 feet
in rivers on gravel, sand, or mud
(Parmalee and Bogan 1998). Large
creeks with high water quality. Often
found at water's edge next to current
(Watters et.al. 2009).
Distribution: Widespread in North
America. From Texas through the
Great Plains states to South Dakota
and Minnesota, east to Pennsylvania
then down through Tennessee to
Mississippi.
Collection notes: The Pistolgrip is
fairly rare in Nebraska. Relict shell is
common in the Big Blue and Big
Nemaha Rivers and shell have also
been found in Logan Creek. The only
live one that has been found was one
that I found in the Big Blue River in
2002. There are numerous
archeological records from the
Republican River basin and near the
Missouri River in east-central
Nebraska.
Comments: A single live collection in
the past 100+ years of looking. The
fragmentation of the Big Blue and
dewatering of the Republican along
with a limited number of host fishes
may have hurt. They may still be
present in Big Blue River but the odds
of that are poor. A thorough dive
survey would be needed to find out.
