World Congress of Malacology Antwerp ... - Unitas Malacologica

in Utah (e.g. Oxychilus alliarius, Arion intermedius), but Oxychilus cellarius appeared only in
Colorado (two sites); similarly within Colorado A. circumscriptus was restricted to localities around
Boulder.
The widespread slug Limax maximus Linnaeus, 1758 (Gastropoda: Pulmonata):
species boundaries and redescription
Hyman, Isabel T. 1 ; Klee, Barbara 1 ; Schneppat, Ulrich 2 ; Haszprunar, Gerhard 1
1. Zoologische Staatssammlung München, Münchhausenstraße 21, D-81247 München, Germany,
Email: Isabel.Hyman@tf-limax.org; Barbara.Klee@zsm.mwn.de; Haszi@zsm.mwn.de
2. Bündner Naturmuseum, Masanserstr. 31, CH-7000 Chur, Switzerland,
Email: ulrich.schneppat@bnm.gr.ch
Limax maximus is a terrestrial slug belonging to the family Limacidae (Mollusca, Gastropoda,
Pulmonata). It is the type species of Limax and is also one of the most widespread and externally
variable species in the genus. In addition, L. maximus has been introduced throughout the world.
Before any biological control can be considered, L. maximus needs to be well understood in its
natural environment.
Limax maximus can be distinguished from most other Limax species by the presence of a uniformly
pale sole and spots on the mantle as well as the body. Considerable colour variation exists, however:
The background colour can range from pale cream to dark grey, and patterns vary considerably from
few spots to thick longitudinal stripes. Some forms are almost completely black, with spots just
visible at the edge of the mantle. The objectives of the present study were to sample specimens of L.
maximus from throughout the geographical range and across the full spectrum of colour morphs in
order to use anatomical and molecular data to determine the limits of the species.
Our molecular dataset was based on 1334 nucleotides of the mitochondrial gene cytochrome c
oxidase subunit I (COI) for more than 30 specimens of Limax maximus from throughout Europe and
from Australia, New Zealand, North America and Hawaii. Additional Limax and other limacid
species were also included. Analysis using Bayesian Inference indicated that all L. maximus
specimens belong to a single species, with overall variation of 1.4%. Slugs of similar external
appearance did not group together.
Dissections reveal little variation within Limax maximus in any organ system. Slight differences in
the length of the blind penis tip did not correspond with any grouping on the molecular tree.
However, L. maximus can clearly be distinguished from other Limax species based on anatomy. The
most important characters include the length and coiling of the penis and the position of attachment
of the vas deferens and penis retractor muscle.
Evolutionary ecological aspects of the geographic variation in the intertidal gastropod,
Monetaria annulus (family Cypraeidae)
Irie, Takahiro
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan,
Email: irie@bio-math10.biology.kyushu-u.ac.jp
As with the other cypraeid species, Monetaria annulus is particularly suitable for investigating
molluscan body size variation because of their determinate growth. In Okinawa Island (Japan), M.
annulus is found in the lower intertidal zone on fringing reefs, and exhibits a remarkable geographic
variation in body size at maturity; soft body size in adult individuals is smaller in shallower habitats
located at the landward margin of reef flats, partially covered by coralline rubbles and sand (referred
to as “inshore habitats”) than in slightly deeper habitats on the outer edge of reef flats, characterized
by exposed rocky substrates (“offshore habitats”). Through a common-garden experiment in which
minute juveniles collected from the two types of populations are reared in the same environmental
condition in the laboratory, I recently demonstrated that phenotypic plasticity, instead of genetic
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