Ross;
 The eelgrass limpit you describe from Nova Scotia was mentioned in
American Seashells (Abbott 1956 Seventh Printing p.105 and in the Second
Edition pp.32-33. as Acmaea testudinalis testudinalis (Müller, 1776) form
alveus Conrad, 1831. The specimens found in Boundary Bay compare to a
specimen of Lottia alveus I have in my collection which was collected by G.
Willett at Grants Island, Alaska.
 Material for DNA study has been sent to Dr. Lindberg in California so
there should be no question about what we have after that is done.
George

>First, Splendid site
>(http://modena.intergate.ca/personal/seashell/bcframe.html) - great
>Photos, especially of live animals!!  Bravo.  The species you are
>calling Lottia alveus (Conrad), seems to be an elongated form of pelta
>Rathke, or perhaps strigatella - it is lighter, more transluscent, but
>if you take a look at the specimens you find in the vicinity, NOT on
>Zostera, i think you will find they are the same species.  A similar
>thing occurs in Nova Scotia at a few localities where eel-grass
>communities are well established - Lottia testudinalis (Muller) has (in
>the absence of alveus, which formerly occupied that habitat) expanded
>its normal niche to take advantage of the juicy algae on the grass
>blades.  It is unknown whether those engaging in this specialization
>comprise a genetically distinct sub-population, or whether they just
>grow ligher and more elongate on the eelgrass, as a response to
>different living conditions (would make a great honors thesis!!).  There
>are no references, since i seem to be the only one around here that has
>taken serious notice of the phenomenon.  To find ths occuring on the
>other coast, is interesting, to say the least.
>
>From the rather dry (but still great!!) North,
>Ross.
>
>Peter Egerton Wrote:
>
>Hi all,
>
>In adding species to my Web site I've come across something a little
>puzzling. I Boundary Bay, just south of Vancouver BC, I collected a
>number of limpets that I've labeled Lottia alveus. This limpet was very
>abundant living on eelgrass stems.
>
>What puzzles me is that a number of Web sites call it an extinct
>species. One is http://ucmp1.berkeley.edu/davidl/Pages/biblio.html which
>lists a paper written in 1991:
>
>Carlton, J. T., G. J. Vermeij, D. R. Lindberg, Debby A. Carlton and E.
>C. Dudley. The first historical extinction of a marine invertebrate in
>an ocean basin: The demise of the eelgrass limpet Lottia alveus. Biol.
>Bull. 180:72-80. 1991