TerralogNEWS101
4
ccording to current wisdom, the
genus
Amphidromus
contains 87
species that are divided into two
subgenera.
Amphidromus atricallosus
belongs to the
nominate subgenus
Amphidromus
, and
the second subgenus is
Syndromus
. The
two subgenera are distinguished by
anatomical details, but we will consider
just oneof themhere.
Left- or right-handed?
Thisdetail relates to thedirection inwhich
the shell of the snailwinds. In themajority
of snails this is genetically determined. If
the shell is held with its apex pointing
upwards and the opening towards the
observer, then it is possible to determine
whether it is left-handedor right-handed.
Forexample,theEdibleSnailorEscargot is
normally right-handed and left-handed
A
For around three years gorgeous yellow, light blue, andwhite snails have
been imported to Europe from Thailand.With a shell height of around 5
cm and their splendid porcelain sheen, these are very impressive
creatures.The soft parts of these snails are colored tomatch their shells.
Theybelong to the taxon
Amphidromusatricallosus leucoxanthus
.
Porcelain tree snails
bySebastianZimmer
Wirbellose
specimens are extremely rare. It is said
thatonlyone in20,000 specimenshas the
latter type of shell! But it is quite normal
for the subgenus
Amphidromus
to have
both left-handed and right-handed
individuals in any given population. The
technical term for this is amphidromine,
meaning “winding in both directions”. By
contrast, in the subgenus
Syndromus
the
direction in which the shell winds is
largely genetically determined. All but
two species of
Syndromus
– one right-
handed, one amphidromine – are left-
handed.
Theporcelain tree snail
Amphidromusatricallosus leucoxanthus.
Nosexual dimorphism
Under no circumstances should the
