World Congress of Malacology Antwerp ... - Unitas Malacologica

1. Prepare boiling hot freshwater, a small beaker, forceps (with fine tips), a small syringe, a petri
dish, and a stereomicroscope.
2. When the live animal in the beaker crawls on the bottom, pour boiling hot water over the animal,
which is killed immediately. Some seconds later take the specimen out of the hot water, hold it with
two fingers of one hand and hold the forceps with another hand.
3. Under the microscope, grab the foot with the forceps and pull carefully to just separate the
columellar muscle from the shell.
4. Pull the foot again in a petri dish filled with cold water as under 3. With coiled gastropods,
unscrew the specimen by approximately 1/4 whorls. If it is difficult to move the soft parts, inject
water into the aperture gently with the syringe. Repeat it several times, then you will get an empty
shell and the complete soft parts.
With this method, we can obtain intact shells and soft parts for multiple purposes such as
conchological observation and gross anatomy. DNA can also be extracted from those soft parts
because DNA is stable under high temperature. The boiled animal can be dehydrated in alcohol. We
can prevent the negative effect of DNase (by heat) and magnesium (by washing in freshwater), both
of which decompose DNA.
A challenge to the relationships of “Omphalotropis” (Caenogastropoda: Assimineidae)
Fukuda, Hiroshi 1 ; Ponder, Winston F. 2
1. Conservation of Aquatic Biodiversity, Faculty of Agriculture, Okayama University, Tsushimanaka
1-1-1, Okayama 700-8530, Japan,
Email: suikei1@cc.okayama-u.ac.jp
2. Australian Museum, 6 College Street, Sydney, New South Wales 2010, Australia,
Email: winston.ponder@austmus.gov.au
Most islands of the Indo-Pacific region have terrestrial assimineids. More than 100 species were
described as “Omphalotropis” or allied genera in the 19th Century, but data on their anatomy is
sparse.
We have anatomically examined these snails from Mauritius (including the type species of
Omphalotropis, O. hieroglyphica), Reunion Id, SW Australia, Lord Howe and Norfolk Ids, Papua
New Guinea, New Caledonia, Palau and Guam and will be extending this survey.
The kidney in some species has an anterior lobe which extends forward in the roof of the pallial
cavity. While this is unknown in other rissooideans, it is similar to Cyclophoroidea and some
terrestrial Littorinoidea. The anterior kidney lobe is variable in size and shape, but is similar in
species from the same island group. This, and other characters, suggest that species from each
geographical region radiated independently. Species from SW Australia and Lord Howe and Norfolk
Ids lack the anterior kidney and represent the plesiomorphic condition.
Using other characters, at least two major groups can be recognized: Group 1 from the Indian Ocean
(Mauritius, Reunion Id, SW Australia), Lord Howe Id and Norfolk Id; Group 2 from New Caledonia
and northwards in the Pacific. The groups are defined by the following characters:
Group 1. Snout simple, ctenidium present, several small seminal receptacles and anterior oesophagus
lacks external gland.
Group 2. Snout with a fold (“buccal cape”), ctenidium absent, seminal receptacle large, anterior
oesophagus with large gland on the right.
While the above characters appear to indicate phylogenetic relationships at a supra-generic level, the
shell and opercular morphology, the main characters used in determining generic status in the past,
are extremely diverse and convergent.
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