When I purchased a clump of floating plants (Elodea/Egeria densa) from
an aquarium and was examining the clear bag on the way home I noticed a
snail was a stowaway on my purchase. Just a single snail (like most of
you I examine every leaf on a new plant before placing it in a tank,
just habit I guess

I placed it in an empty tank (no fish or other animals, just plants).
The following is an attempt to I.D. this species, whose behavior and
form are like nothing I've seen. This has all taken place in a timeframe
of the last six months.

Within a week I noticed my first clump of snail eggs in the tank. Clear
masses of jelly with clear eggs in them cemented to the water line on the
glass sides or to plants at the water line. If the eggs are laid against
the glass, you can use a lens to watch the embryos develop. They grow
rapidly, pretty soon the jelly mass is dotted with miniature snails all
perfect copies of their parent. At this point they break free and the
jelly dissolves. As I said, they are perfect mini copies of the parent,
including their shells (traditional compact whorls). As they get larger
a metamorphosis occurs, their shell shape changes to ramshorn, in other
words no longer a round traditional shell but one that is severely
compressed on both sides and is shaped like a cinnamon roll, only unlike
the ramshorn snail you see in pet shops they don't carry their shells
upright, it rests on one side. Picture that same cinnamon roll laying
on a table with a snail's head sticking out of the final whorl.

I scratched my head at this point, thinking I must have another snail
species in this tank, no way could these juvenile snails have come from
this parent. But I knew no other snail was present. As they grew their
shell shape morphed again, back to the original version! Since then it
has stayed that way and because the first batch of babies is about the
size the original snail was when I first brought it home it looks like
this is the final form of shell shape for the species. But the
weirdness is much more than that! There are two distinct variations
in this population that differ not only in color but in body shape!
Let me explain:

Type 1. Body color white. Tentacles above eyes VERY SHORT AND WIDE,
shaped like shark fins. Body/foot short and rounded at the
tail end. Shell coloring whitish through yellowish to light
brown. Shell is formed CLOCKWISE, the whorls (if you were
looking at the shell with the pointed tip facing you)form
via clockwise rotations around the shell.

Type 2. Body color gray/brown. Tentacles above eyes LONG AND TAPERING,
like traditional land snail or slug tentacles except the eyes
are not located at their tips but are below them. Body/foot
long and tapering at the tail end, coming to a point. Shell
coloring yellow brown to reddish brown. Shell is formed
COUNTERCLOCKWISE, the opposite of Type 1! Every snail so far
without exception has followed this clockwise/counterclockwise
difference depending on their type. Amazing!

A couple of more points; The original parent snail of this colony
is a Type 1, it has now reached a shell length of a little under 1 inch
(2.5 cm) from tip of shell to other end. It is about 3 times larger
than it was when I first brought it home. Although my guess is
Type 2 is the wild type and Type 1 is a recessive form, Type 1 snails
outnumber Type 2 snails dramatically in every litter so far.

If you have any thoughts or guesses on this species' I.D. please let
me know either on the list or in private email. Any other info or
online sources of information for this strange variation you could
pass on to me? Personal experience? All information will be
appreciated, thanks.

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