San Francisco Bay Study / Polydora origins

Geoff Read at
Mon Nov 4 20:37:03 EST 1996

James Blake wrote:

> ... I had some problems calling up the document on Netscape, but was 
> successful with my AOL browser. 

Thanks Jim. 
A vital small correction of (h to n) in the URL to:

The parent page is the also interesting  "Nonindigenous Aquatic Species
(NAS) information resource" page at URL:

Be warned! The online paper is one file of 0.8 Megabytes.

> As most of you know, (Blake and Maciolek, 1987: Bull. Biol. Soc. Wash. 
> 7) referred this species to synonymy with the type species of Polydora, 
> P. cornuta Bosc, 1802.  This synonymy has now been widely accepted and 
> the name P. cornuta is regularly appearing in published accounts of the 
> species. 

I have used P. cornuta, but I see at least 15 papers since 1987 which do
not, mostly (but not all) from ignorance I would suspect, rather than
having differing views from B&M. But I don't think anyone will be too
surprised if there are not more complications and interesting things to be
found in the status of P. ligni-like species. 

> ... The statement that the species is native to the Atlantic is, in my
> mind, not substantiated.  In fact, there is systematic evidence that
> the species very likely originated in the Pacific.  

It is not easy to prove an introduction for inconspicuous animals such as
most worms. It is even more difficult to prove an origin. Has it ever
been done for a polychaete? Is it a realistic aim? Cladistically analysing
'related' species (if first they are indeed good species) seems to be a
useful approach in biogeography of some groups but would it shed light on
certain worms now that they have hitchhiked in every possible direction?

I personally would not baldly state as do Cohen & Carlton that
"Heteromastus filiformis is native to the Atlantic coast of the United
States" even if I happened to believe it. I would agree with the statement
that "more than one species may be involved" in records of H. filiformis.
I don't think I'd say without qualification that  "Ficopomatus
enigmaticus is an Australian worm" (possible, even probable, but unproven
in my opinion).

  Geoff Read < at>

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