Possible origin of Hydroides elegans

Harry A. ten Hove hove at science.uva.nl
Tue May 20 07:57:28 EST 2003

Dear annelideans,

Not for the first time I was asked my opinion about the possible origin of 
the fouling species Hydroides elegans. Five years ago I gave a lecture 
on the topic of shiptransported serpulids during one of the ICES 
meetings, a slightly adapted transcript of what I said is given below. 
Maybe you can shoot at it, in order to get a better hypothesis.  

As for Hydroides elegans, it probably is the most widespread harbour-
fouling serpulid in tropical and subtropical conditions in both Old and New 
World. Again, it is very difficult to reconstruct its centre of origin. We do 
have some pointers. H. elegans was first described by Haswell (1883) 
from Sydney Harbour, but this does not necessarily mean that this is the 
centre of origin. The first Mediterranean record of elegans dates back to 
1888, from a fouling community in the harbour of Naples (Zibrowius 
1992: 91). In the Mediterranean, H. elegans is restricted to lagoonal and 
harbour communities, it is absent from the open coasts. The same holds 
for the tropical Antillean island of Curaçao, where H. elegans was found 
for the first time in the main harbour Schottegat by me in 1970*, and only 
recently (1975-1985) spread into some other semi-enclosed lagoons, 
where it is replacing the local lagoonal species (sanctaecrucis and 
alatalateralis). From this we may infer that elegans probably is not 
indigenous to the Antilles. On the other hand, H. elegans seems to have a 
more natural distribution in Australia. According to Allen (1953) it 
occurred rarely other than on certain sea-weeds at a depth of about 20 
metres at the time of its discovery in 1883. This, and certainly the depth 
of 20 metres, in my opinion smells of natural occurrence rather than of 
introduction by shipfouling. Allen mentions that observations made by 
docking officers indicate that elegans was seldom, if ever, seen on ships 
fouled in the thirties, whereas it was the most important fouling organism 
in Port Jackson in the fifties. He hypothesizes its rise in importance to be 
due to the increasing pollution in the harbour, a hypothesis corroborated 
by later research by Moran & Grant (1984). Furthermore, H. elegans is 
part of a complex of 6 taxa (Hydroides norvegicus Gunnerus, 1768, 
longispinosus Imajima, 1976, multispinosus  Marenzeller, 1885, 
nanhaiensis  Wu & Chen, 1981, H. centrospina**  Wu & Chen, 1981), of 
which the last 4 occur in tropical Australia and Indonesia***. In my eyes, 
this all makes an Australian origin the most likely.  

*sifting through older collections of P. Wagenaar Hummelinck I recently 
(re)discovered specimens in fouling samples from a Venezuelan 
Destroyer in Schottegat (100dreds) and a few from a buoy in 
Caracasbaai, both records from 1955, and two specimens from outer 
Piscaderabaai in 1967, so it probably will have been introduced at an 
earlier date than 1970. However, this does not change my views, in very 
many samples by Wagenaar hummelinck from enclosed lagoons earlier 
than the seventies elegans is not found.  

**Fiege & Sun, 1999 synonymized centrospina with longispinosus.

***I left out the implied biogeographic axiom that as a general rule, that 
part of the globe in which at present a natural group of animals is 
represented by the largest number of species must be considered the 
centre of its dispersal. I know there are exceptions to this "rule", but 
combined with the other arguments . . . . . Also, the "natural group" has 
not yet been corroborated by a cladistic analysis, but those efforts I 
made, all placed the mentioned taxa in one clade.  


dr. Harry A. ten Hove
Zoological Museum,
University of Amsterdam
POB 94766, 1090 GT AMSTERDAM

TEL. 3120 5256906
FAX. 3120 5255402

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