Type localities and dispersion of species

Dani Martinez dani at azathoth.ceab.es
Tue Dec 5 05:59:03 EST 1995


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





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