- Range:
Blue = current range
Hollow circles = former range
- Status in Kansas:
Extirpated
- North American Status:
(From NatureServe)
Area of occupancy of this
species has been drastically reduced (near 50%) with continuing decline of populations.
Range extent has also been reduced as the species is extirpated from several U.S. states
(Indiana, Kansas, Nebraska, Ohio) and many of the remaining populations have poor or no
viability. The species has largely been reduced to a relatively few disjunct sites, some
of which may not be capable of reproduction either through loss of fish hosts or adverse
environmental conditions (e.g., hypolimnetic release from reservoirs). Only the Gasconade
and Meramec Rivers of Missouri and perhaps also in the Upper Clinch River, Tennessee are
fairly stable for now with the remaning populations in decline.
Historically, this species occurred throughout much of the Mississippi River system with
the exception of the upper Missouri River system, uppermost Ohio River system, Cumberland
and Tennessee River systems, and some tributaries in the lower Mississippi region of
Arkansas. Historically, it is known from 45 streams in 15 states including: upper
Mississippi River system (Mississippi River); lower Missouri River system (Missouri
River?); Ohio River system (Ohio River); Cumberland River system (Cumberland River);
Tennessee River system (Tennessee River); and lower Mississippi River system (Mulberry,
Ouachita Rivers). Two occurrences reported recently from the Duck River in a reach less
than 30 miles long.
- Comments:
The spectaclecase has an elongated shell, its length being three times its height.
The ventral surface is concave which gives the shell a banana-shaped appearance. The color
is dark brown turning toward black with age. The spectaclecase is found in-between and
under the edges of large boulders in deep stretches of rivers. This habitat is not typical
of most other mussels which usually inhabit gravel or silt substrates. Relic shells were
recently found in the Marais des Cygnes River but no live individuals have been found in
Kansas.
- Fish Hosts:
unknown
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