[Annelida] seta vs chaeta

Sergio Salazar savs551216 at hotmail.com
Thu Apr 20 14:41:15 EST 2006

Dear Geoff,

Sorry to bother you again. Please forward the following message to Annelida 
subscribers. I tried the former address, but something went wrong. Thanks a 

. . . .

Dear colleagues,

During the evaluation of some of my recent papers, I have noticed a variable 
level of insistence on using chaeta instead of seta (and derivatives). 
However, as I will show below, although some authors regard them as 
equivalent, they are not; the former meaning long hairs, while the latter 
indicates short (rigid) hair. Since the latter are more akin to the annelid 
structures, Polychaeta (or its antonym, Oligo-) might be wrongly 

Jaeger (1931) in his classical and succinct volume makes both words 
equivalent. Thus, for chaet (p. 26) he indicates that it means both hair and 
bristle, while for set (p. 133) it only gives bristle.

After Brown (1956:195), chaeto- is formed after the Greek word chaite 
meaning long hair or mane, and the entry asks to see hair.  Under hair (p. 
390 ff), it includes several names made after chaet. In the same section (p. 
392), it has the Latin word seta which is feminine and means bristle, and 
this is repeated under seta (p. 699). This information s also available in 

The Collins Cobuild dictionary (1993) states that bristles (p. 174) are: 1) 
thick, strong, animal hairs that feel hard and rough, or 2) short, thick 
hairs that grow on part of your body after you have shaved it. On the 
contrary, mane (p. 883) is a horse’s or lion’s 
 long hair that grows from 
its neck.

Thus, there are two features making these words differ; they are the 
relative length and stiffness of the hairs they were originally employed 
for. Therefore, in the worst scenario both usages should be allowed, and 
perhaps the use of seta (and derivatives) should be preferred over chaetae, 
because they are better etymologically applied, despite the fact that the 
taxon name is Polychaeta.


Brown RW 1956 Composition of Scientific Words. Smithsonian, Washington, 882 

Collins Cobuild (Collins Birmingham University Language Database) 1993 
English Language Dictionary. Harper Collins, London, 1703 pp.

Jaeger, E.C. 1931. A dictionary of Greek and Latin combining forms used in 
zoological names. Thomas, Springfield, 157 pp.

Best wishes,


More information about the Annelida mailing list