[Annelida] seta vs chaeta

Geoff Read g.read at niwa.co.nz
Sun Apr 23 22:58:21 EST 2006

Jim Blake:
> With regard to morphology, I would urge editors and publishers to not assume
> that "chaeta" is universally preferred over "seta." As noted, there is no
> written rule and no concensus among all workers in the field. Submitted papers
> should use the form preferred by the submitting authors. 

Language, including technical terminology, is a product of convention or 
collective memory and will evolve due to usage. I had the impression that 
there was a modern consensus for opting for chaeta—demonstrably not a 
unaminous consensus  though. 

I assume we are agreed the respective variants of chaeta and seta mean exactly 
the same but are just different spellings due to the history of two and more 
languages. So there is no problem to be solved there. The 'chaeta' form  does 
distinguish annelid terminology from that for arthropods and appropriately 
matches  the taxon name. These benefits have already been canvassed. 'Chaeto' 
in 'Chaetopoda'  predates Linnaeus by some decades, so there is a long 
association of the spelling closer to the Greek with worms with bristles. It 
also perhaps has the virtue of not imposing an English-origin spelling as a 
technical term on those whose equivalent word for setae is spelled 

Chaeta and seta are particularly useful as combining forms. Rather than saying 
'the bristles of the notopodial lobe' we say more succinctly 'notochaetae' or 
'notosetae'. By the way both noto & neuro are also Greek so 'notochaeta' 
'neurochaeta' are a purer formulations.  However it is below that level when 
describing  chaetal morphology  that our problems of impreciseness really 
start. Spine and uncinus  (both Latin) mean whatever one wants them to, and 
once one gets into the vagueness of the English 'hook' (or the equivalent in 
other European languages) one begins to despair.  

Looking through the conference volumes it is evident that 'chaeta' and 
chaetiger didn't make much of an impact for a long time if indeed first raised 
in 1984.  But David George was indeed using those in print in 1985 (British 
fauna synopses series) which makes it possible he talked about it in 1984.  

Finally I noticed the insidious chaeta term even makes it into Jim's Atlases  
as 'achaetous' on p69 of part 1.  I don't think there is a 'seta' equivalent 
in common use (asetigerous to me means without setigers, not without setae, so 
one couldn't use it for a particular achaetous segment).


  Geoff Read <g.read at niwa.co.nz>

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