Andrew,

Yes, Vitta usnea lives in brackish to freshwater, one of several problems,
questions, issues, etc. with this species.  Say (1822, who named the species
Neritina reclivata) wrote, "I found this species in great plenty, inhabiting
St. John's river in East Florida, from its mouth to Fort Picolata, a
distance of one hundred miles, where the water was potable."  I would say
100 miles inland is pretty much beyond tidal influence and can be safely
called freshwater.  It has been listed by various authors as direct
developing with crawl away juveniles.  BUT, even this is unclear.  According
to Andrews (1935:42) this is one of the few nerite species with direct
development.  Specimens kept in small glass dishes laid eggs that hatched
into miniature "crawl-away" adults bypassing the more typical veliger stage.
This has not been observed in my aquariums.  And, young Vitta usnea (<6 mm)
were collected on turtle grass in three feet of saltwater off Gulf Breeze,
Florida (Cheshire, 2004); indicating a tolerance for salt water.  There may
be two forms (there is certainly enough, though not dramatic, variation in
radular and shell morphology), one that has evolved to a completely
freshwater existence and the other that has remained diadromous - and is
still tied to the sea.

Tom Eichhorst

> -----Original Message-----
> From: Conchologists of America List [mailto:[log in to unmask]]On
> Behalf Of Andrew Grebneff
> Sent: Wednesday, August 11, 2004 8:19 AM
> To: [log in to unmask]
> Subject: Re: Freshwater barnacle
>
>
> >Seems to me Vitta usnea (Roeding, 1798), better known as Vitta reclivata
> >(Say), might occur in estuaries.
> >Henk K. Mienis
>
> Funny, in 1990 I found a colony of these flourishing in a tributary
> of the Peace River, not too far from Shell Ck, Charlotte Co, Florida.
> The water is utterly fresh (pollution aside) anf with a good flow.
> --
> Andrew Grebneff
> Dunedin
> New Zealand
> Fossil preparator
> <[log in to unmask]>
> Seashell, Macintosh, VW/Toyota van nut
>
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