[Annelida] help on determination of Praxillella and Clymenura

José Eriberto Assis via annelida%40net.bio.net (by eri.assis from gmail.com)
Wed Oct 21 10:06:06 EST 2009

Dear Dr. Barbara

I have been work with Madanids - Phylogenetic Analysis of the
Maldanidae Polychaeta Annelida, in the thesis to obtained the title
of master, and I had some problems with some species without one the parts.
For the Maldanids is very hard to idetifly only anterior or posterior end.
If you have many specimens you can identifly to compare to specimens. In
relation to the *Praxillella *and* Clymenura *both are  very hard becouse
the main diferences consist in the pygidium. You can make draws of the
uncinus and chaeta, and pheraps  you can to identifly to species.
The problem also consist in that the description some species yet
insuficient to make to compare. However, good luck.
Best wishes
Eriberto De Assis
On Tue, Oct 20, 2009 at 6:20 AM, Barbara Mikac <barbara.mikac from cim.irb.hr>wrote:

> Dear colleagues,
> Can you advice me how can I determine Praxillella species based only on
> the front part of the animal containing the head (thus it's not possible
> to count the number of chaetigers). Sometimes I also have only pygidium,
> but then usually without the front part. In the Adriatic Sea there
> should be present: P. affinis, P. gracilis, P. praetermissa and P.
> lophosetosa. P. gracilis should be easy to determin because it should
> have distinctly elongated palpode on the prostomium. P. affinis should
> have ocelli and P. praetermissa not. But what about P. lophosetosa? Are
> the characteristics I mentioned above sufficient to distinguish the
> species anyway?
> I also have a problem to determine Clymenura clypeata and C. tricirrata,
> that could be both potentially found on the stations I am working on.
> It's quite easy when I have the pygidium, because if it has muscular
> ring with three cirri originating from it, I know it's C. tricirrata. On
> the other hand if it only has a muscular ring forming a pygidial plate
> and an anal cone with a well developed ventral valve (Garwood, 2007) I
> know it's C. clypeata. Most of my animals unfortunately lack the
> posterior part/pygidium. Is there some way to distinguish two species
> based on the front part of the animal?
> Thank you very much for your help!
> Barbara
> ________
> Barbara Mikac, M.Sc.
> Marine Research Centre
> Rudjer Boskovic Institute
> G. Paliaga 5
> 52210 Rovinj
> Croatia
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Universidade Federal da Paraíba
Centro de Ciências Exatas e da Natureza
Departamento de Sistemática e Ecologia
João Pessoa, Paraíba, Brasil.
CEP: 58051-900.
e-mail: eri.assis from gmail.com
(55) 83 - 8889-8791 (celular/mobile)
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