More on the FW Alaskan Polychaete

Aaron Baldwin jsapb at gci.net
Mon Nov 8 19:41:02 EST 1999


Dear group,

I spent a few hours today examining the FW polychaetes I had mentioned 
in an earlier post. By request I will post a more detailed description. While I 
am reasonably familiar with polychaete morphology, there is a possibility 
that I have erred in the identification of certain parts, so please forgive if 
any "impossible" combinations of traits appear!  

The prostomium is pointed in some individuals, rounded in others. I can 
find no evidence of prostomial appendages except in one specimen there 
appear to be scars or remants of what could be palps as is seen in 
Spionids. The prostomium has four black eyes, with the first pair being 
slightly larger and further apart than the second pair.  

Branchiae are simple, flattened, filliform (?) and are about 4 times as long 
as wide. The first setiger that I can see undisputable branchiae on is 
setiger three. The branchiae are dorsal to the parapodia and appear, in 
some places, to be partially fused with the notopodium. The posterior end 
of most of my specimens is either missing or damaged, so I do not know 
how far back the branchiae extend. On one specimen with a complete 
posterior region I can find no branchiae on these setigers. However, the 
posterior setigers have many fine cirri (maybe branchiae?), about 4-7 on 
each side of each setiger.  

The parapodia are biramous. The setae (I couldn't determine neuro- from 
notosetae, I believe I was looking at notosetae) are simple limbate 
capillaries. Bidentate (?) hooded hooks appear from setiger 20 on back 
(one specimen has hooks on setiger 18, and another may have been as far 
back as setiger 22).  

Thanks again for any input, -Aaron

Aaron Baldwin <jsapb at gci.net>


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