[Annelida] Polychaete detective work

Geoff Read via annelida%40net.bio.net (by g.read from niwa.co.nz)
Wed May 14 15:57:35 EST 2008


>>> On 14/05/2008 at 11:30 a.m., "J. Kirk Fitzhugh" <kfitzhug from nhm.org> wrote:
>  [...] At least 'acicular uncinus' has the proper empirical relation.
> 
> Geoff Read wrote:
>> Come to think of it, 'acicular uncinus' (a needle hook) for a long-handled 
> 'uncinus' is contradictory [...]

A hook is a hook is a hook. One can call it an acicular uncinus if that is traditional for taxonomists in a particular family. But to most working on Polychaeta it is simply a hook, whereas uncinus brings to mind forms that somewhere are not cylindrical but flattened (plate-like). The extra verbiage of the combo I suggest is not helpful for clarity for the non-specialist. Hence possibly the treatment adopted in the Intkey family key of Chris & Kristian. 

Here FWIW are the notes in the family key 

"Hooks are unjointed, stout, distally bent chaetae which are generally bifid or multidentate (exceptions are those in some Eunicidae and Onuphidae). They differ from spines in being thicker and more recurved distally, and from uncini by having a long shaft. Chaetae referred to in the literature as 'long-handled uncini', such as those in the thoracic neuropodia of Trichobranchidae, are considered here as hooks. Hooks may have various types of guards or hoods covering the apex, or they may be unprotected."

"Uncini are short, beak-like chaetae usually with a heavily dentate crest and no shaft (the shaft may be replaced by two ligaments attached to each end of the uncinus); rarely is the shaft extended into a long-handle."

Cheers,

Geoff

-- 

 Geoff Read <g.read from niwa.co.nz>
   http://www.annelida.net/
  http://www.niwascience.co.nz/ncabb/





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