For a non-marine species, it may be possible to verify that the habitat is destroyed.

No specimens being collected for decades also suggests extinction; however, I know of no records of "Pleurobema" stabile (aka murrayense) between 1958 and 2000.  However, as only two specimens have been found with intensive searching, it probably won't last long.

    Dr. David Campbell
    Old Seashells
    University of Alabama
    Biodiversity & Systematics
    Dept. Biological Sciences
    Box 870345
    Tuscaloosa, AL  35487-0345 USA
    [log in to unmask]

That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa

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