[Annelida] help on determination of Praxillella and Clymenura

Lovell, Larry via annelida%40net.bio.net (by LLovell from lacsd.org)
Tue Oct 20 17:05:36 EST 2009

-----Original Message-----
From: Lovell, Larry 
Sent: Tuesday, October 20, 2009 2:37 PM
To: 'Barbara Mikac'; Polychaete mailing list
Subject: RE: [Annelida] help on determination of Praxillella and


Try staining your anterior fragment specimens in an ethanol solution of methyl green.  A solution dark enough to still see the animals in the stain should work well, too dark and you will have a hard time retrieving small specimens.  Or you can hold a specimen with your forceps and submerge it into the solution and hold there for 5-10 seconds or longer if necessary.  Place the specimen in fresh EtOH to destain yielding a pattern that will persist for several hours to several days.  The MG stain will eventually fade completely (some specimens/species may take much longer).  Maldanid species can have very specific methyl green staining patterns that can be used top ID incomplete specimens.  Stain a few of your voucher specimens for which you have a positive identification to establish the staining patterns for your known species and work from there for the fragmented specimens.  If there are 10-12 setigers present (sometimes fewer), that can usually be enough to tell pattern differences.  There will be thoracic and abdominal patterns.  The methyl green is reported/thought to stain mucous secreting glandular areas.

As an example, I can send (sent to Barbara) staining patterns of two local southern California species, Praxillella pacifica Berkeley 1929 and Euclymeninae sp A SCAMIT 1987, a provisional species. Credit goes to Kelvin Barwick, OCSD for the images.  PDF's of the images did not go through to Annelida (as expected), please request them from me if you would like them.

Methyl green staining patterns are useful taxonomic characters in other several other polychaete families:  especially the Maldanidae (Green 1987, 1991, 1997), Capitellidae (Green 2002; Warren et al 1994, Blake 2000), Cirratulidae (Blake 1996, 2006; Dean & Blake 2009; Doner & Blake 2009), and Sabellidae (Tovar-Hernandez 2007).  

Hope this helps.


Lawrence L. Lovell
Biologist II
Ocean Monitoring Research Group
County Sanitation Districts of Los Angeles
24501 S. Figueroa St.
Carson, CA 90745
(310) 830-2400  X-5613 office
(310) 952-1065 fax
llovell from lacsd.org <mailto:llovell from lacsd.org>

-----Original Message-----
From: annelida-bounces from oat.bio.indiana.edu
[mailto:annelida-bounces from oat.bio.indiana.edu]On Behalf Of Barbara Mikac
Sent: Tuesday, October 20, 2009 2:21 AM
To: Polychaete mailing list
Subject: [Annelida] help on determination of Praxillella and Clymenura

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 Mikac, M.Sc.
Marine Research Centre 
Rudjer Boskovic Institute
G. Paliaga 5
52210 Rovinj

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