> Tridacna gigas (Linnaeus, 1758) appears to be the largest shelled mollusk
> that has ever lived (David Campbell and other paleontologists may have a
> different read on this). I have looked into the literature (full references
> on request) and found that the largest recorded specimen measured 1368.7 mm
> (a little over 4 ft. 5 3/4 inches) and reposes in New York's American Museum
> of Natural History. The paper trail seems to go back a ways (Dillwyn, 1817:
> 214; Rosewater, 1965; Wagner and Abbott, 1990; Pisor, 2005). It was first
> reported in Ireland, and it originated in Sumatera (modern Indonesia).

Probably one of the heaviest-the ammonites had to swim.  The giant
rudists are generally long and proportionally thin, though some were
pushing 2 m (with their bad habit of being fossilized in solid
limestone, measurements can be tricky).  Some inoceramids likewise
rival Tridacna in length, but are rather flat.
Actually, the longest living shelled mollusk (not counting squid pens
as shells) is Kuphus (Teredinidae), with tubes that can be longer than
a T. gigas, though the animal is of course much smaller in other
dimensions.


--
Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------