|First data on the ecology of Philipia mediterranea (Monterosato, 1872)|
|Ricardo Vega Luz|
|Any news whatsoever about this rare species endemic to the Mediterranean is extremely interesting and so I consider it important not only to publish the first photos of the live mollusc but also to give precise information about its habitat. It is rather difficult to obtain a live specimen of Philippia mediterranea (Monterosato, 1872 even here in the south of Spain, where this species seems to be less rare than in other places. In the last few months we have been very lucky to be able to keep two specimens, which were given to us live, in a 200 litre aquarium. One of these, the specimen we have had for the longer time, has been there for over six months and we have not noted the slightest weakening of the animal. Thanks to this we have been able to make some observations about its behaviour. As far as habitat is concerned, data collected shows that the species lives at a depth of about 40 metres on a substratum, in our opinion, of firm mud. Some specimens have been caught together with gorgonias. The zone where they are caught more frequently can be localized in an area between Torre del Mar (Málaga) and Herradura (Granata).||Together with P.
mediterranea, other species have been collected: Aporrhais
pespelecani (L., 1758), Pseudosimnia carnea
(Poiret, 1789), Cymatium corrugatum (Lamarck,
1822) and Ocenebra erinaceus (L., 1758). It is
interesting to note that, on the contrary to what we
thought at the beginning, this species cannot be
considered, on the basis of the data we possess, as a
deep water species. I will not dwell on the description
of the soft parts which are quite well visible in the
photo. Here are the most interesting observations about
the behaviour of the mollusc in an aquarium: The animal
always lives on coarse or fine gravel, normally without
burying itself in it or just partially doing so on some
rare occassions. A few other times it was seen attached
to the upper part of the glass, from which it detaches
itself slowly, thanks to two threads of mucus which come
from the foot, while, at the same time, it withdraws into
the shell and closes itself in almost completely with the
operculum. Its habits are decidedly nocturnal.
During the day and in the presence of artificial light it stays semiwithdrawn in its shell, and seems to be dead.
|In the dark the animal is
more active, even though it has been very difficult for
us to see it. We have just been able to note the change
of its position in the aquarium from one day to another.
So it was not possible for us to observe it while it was
feeding and it is supposed that it does so during the
night. In the considerable number of individuals found
dead, it can be observed that one in four has a hole in
on the body whorl of the shell. It can be deduced that
members of the family Naticidae Gray, 1840, definitely
including Tectonatica filosa (Philippi, 1844)
are regular predators of P.mediterranea.
|La Conchiglia - The Shell
Year XXII - N. 250 - 252 January - March 1990