>  > I am attempting to locate a specialist who tell me something
>  > about what is known about the growth rings of freshwater
>  > shells in this case from the Yucatan, Mexico with particular
>  > attention to one species, Pomacea flagellata.

Doug Jones, with the Florida Museum of Natural History, has done a lot of mollusk growth studies.

If there is seasonality, the stable isotope ratios (13C/12C, 18O/16O) in the shell should reflect this.  Sampling the stable isotopes along the direction of growth should give you a good idea of the number of seasons the animal lived through.

I think that Pomacea is generally annual, though I doubt that all species have been checked.  Thus, the shells may represent no more than a year total.


    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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