Dear Anelidans,
Talking about the importance of type localities,
Jim Blake writes:-
> Does anyone out there have any comment on this issue or examples of
> species that have obviously been moved around by ships or other means?
Concerning type localities, I had the opportunity to describe a
new capitellid genus from a brackish, shallow-water, enclosed Bay of the
Ebro'Õs Delta in the Iberian peninsula which I named" ÒPseudomass tu
deltaicus"Ó. It was very abundant there (about 2000 individuals per square
meter). As Mediterranean waters have been (and are being) largely
explored, I thought the species was endemic. I mentioned this possibility
in the original description, and it was the main reason when I decided
this ÒrestrictiveÓ name. A few years latter I was really surprised when
some colleagues start to mention this species from areas different (and
far) of the type locality. Moreover, most of these citations were from
open bays (although the influence of continental waters were always
present).
I do not know whether this could be a case of recent migration,
previous misleading identifications, hazard of looking now at the right
zones, or whatever. The main point is that the name of the species,
directly linked to the type locality, may induce to erroneous
identifications if people do not expect to find a "Òdeltaic""sÓ species out
of a delta.
Concerning the second point quoted from Jim Blakes, we havehere,
in the North Western Mediterranean, a clear example of a species
which main mean of transport (and, thus, invasion) are the small boats
(particularly, their anchors). This is not a worm nor an animal. Is the
tropical alga Caluerpa taxifolia. The origin of the presence of this
algae, toxic for most Mediterranean herbivores, has been attributed to an
escape from an aquarium near the French coasts. Now, the species is
quickly increasing its area of distribution. Some Italian and Spanish
coasts are affected, together with French coasts, and its expansion can
not be controlled by herbivores. In fact, there are no effective grazers
of this algae here. It grows quickly, and grows over the typical
Mediterranean communities. Particularly negative are their effects on the
Posidonia oceanica meadows. This endemic species, probably supporting one
of the most diverse Mediterranean communities, is now being substituted
by virtually monospecific beds at the areas ÒcolonisedÓ by C. taxifolia
(no plants nor animals coexist with this species). As C. taxifolia mainly
occurs in shallow waters, including small sportive harbours, and no
sexual reproduction has been reported till now, small boats carrying
fragments are the main mechanism of dispersion. And it appears to be very
effective.
Although this last comment does not concern directly to annelids,
worms are virtually absent of the bottoms covered by Caulerpa taxifolia
beds. Thus, most of the "Òfuture generations of north western
Mediterranean polychaetologits"Ó would, why not, becom e Òfuture
generations of north western Mediterranean specialist on C. taxifolia"Ó.
Daniel Martin
Centre d'ÕEstudis Avacnats de Blanes (C.S.I.C.)
Cami de Santa Barbara s/n, 17300-Blanes (Girona), Catalonia (Spain)
Dani at ceab.es
