>Is there any indication that fluorescent species are more than incidental? Can some species "see" in the ultraviolet range?<

UV is readily absorbed by water, so only extremely shallow water species or terrestrial species would be able to make much use of it.  Of course, many species are either buried or covered by periostracum in life, so all color patterns would seem to be functionally irrelevant in them, but perhaps there is significance for others.

The fossils I know of show similar patterns under UV to those seen under normal light in modern specimens, so it seems to be merely a more durable component of the regular pigment that fluoresces.  If something had a UV pattern that did not correspond to ordinary patterns, that would provide stronger evidence for functional significance.

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