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Ringed Crayfish, Orconectes neglectus neglectus
The Ringed crayfish has a limited
distribution as can be seen in this map.
None of this range was directly impacted by
the glaciations. This map does argue in
favor of the ancestral Grand watershed. The
center of origin of the species has been
postulated to be in the Ozark Highlands of
southern Missouri.
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The range of the Ringed crayfish is
strikingly similar to that of the Plains
topminnow (Fundulus sciadicus), a fish that
is endemic to the central Great Plains. The
two maps at the right show how similar they
are. It has been suggested that the Plains
topminnow originated in the central plains
and moved downstream into the Ozark
Highlands. A genetic study of the Plains
topminnow.
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found that the two
population centers were related and that they
split some 622,000 years ago. Since this is
during the Nebraskan glaciation, it is
possible that the changing climate and
changes in the drainages caused the split
between the two.
So, if the ancestral Grand watershed
connected these two regions and the Plains
topminnow used it to expand its range south
and east into the Ozark Highlands, is it not
equally possible that the Ringed crayfish
used the same drainage to move west and
Ringed Crayfish range map
Plains topminnow range map
