TerralogNEWS101
5
Themaintenanceof snails is rarelyboringandoffers lotsof opportunities for observation.
all photos:FrankSchäfer
direction of the shell be taken as an
indication of sex.
All
Amphidromus
species are hermaphrodites – in other
words, each individual possesses both
male and female gonads. Anyone who
buys two
Amphidromus
will thus be
buying a pair. The sex organs are so
arranged that they share a common
opening, the ductus hermaphroditicus,
which is branched into a penis and a
vagina. For this reason self-fertilization is
impossible, and insemination must take
place via a second snail. Themicroscopic
details of the penis and vagina provide
important indications regarding the
specific and/or subspecific identity of
these snails.
Known for a long time
The gorgeous shells of the porcelain tree
snailscame to thenoticeofnatural history
collectors centuries ago, and so it is no
surprise that one of the species was
describedas longagoas 1758byC
ARL VON
L
INNÉ
, the father of modern zoological
nomenclature.For a long time these snails
were known only from their shells, and,
depending on the extent of the available
material,
there
were
different
interpretations regarding which snails
were to be classified as species, which as
subspecies, and which as simply color
variants. And to some degree this
remained amatter of debate until a very
short timeago.
The species
Amphidromus atricallosus
was
described by Gould in 1843. According to
the most recent state of systematics it is
divided into four subspecies. The
nominate form
A. a. atricallosus
is
widespreadandoccurs inBurma,Malaysia,
and southandwestThailand. It is found in
associationwith human civilization and is
most easily differentiated from the
following subspecies by having a black or
dark brownparietal callus (see illustration
at theendof this article).
A.a.leucoxanthus
(vonMartens,1864) from
eastern Thailand is very similar and
distinguished mainly by having a white
parietal callus.
