[Annelida] Oligochaete with anal cirri?
(by Geoffrey.Read from niwa.co.nz)
Tue Feb 7 22:36:46 EST 2012
My apologies for the slow response. Thank you to Jim Blake who has seen these previously often it seems, and hit the nail on the head with the morphology, and to everybody also for the suggestions, some of which also hinted at Paraonidae and at Questidae (now in Orbiniidae), which do have similar chaetation. I have rather limited material as yet but I think it's a Levinsenia-like abranchiate paraonid. I'm sure they're reasonably common in the environment, but even at 300 um sieving aren't being retained. They are so thin - of small nematode dimensions.
I've put an order in for a few ethanol fixed samples from the next sampling at this offshore iron sands site. Most of the polychaetes able to live in this material are very small, but getting unfixed live cores to process with meiofaunal techniques is difficult because of the logistics. There are other worms of interest I've seen, and I'd be happy to provide some of these taxa for sequencing if I can get them. Thanks for the offer Adrian.
I was sent the interesting paper of *Giere, Ebbe & Erseus (2007) on Questa, which also includes a new Levinsenia of this type from Hawaii. Much appreciated.
*Giere, O.; Ebbe, B.; Erseus, C. 2007. Questa (Annelida, Polychaeta, Orbiniidae) from Pacific regions - new species and reassessment of the genus Periquesta. Organisms Diversity & Evolution 7(4): 304-319.
The polygordiid with chaeta was not relevant - I was told it is very unlikely any such things exist. The dubious genus Chaetogordius of Moore is probably based on fragments of two taxa.
From: Adrian Glover [mailto:a.glover from nhm.ac.uk]
Sent: Friday, 3 February 2012 5:34 a.m.
Cc: James Blake; Geoff Read
Subject: Re: [Annelida] Oligochaete with anal cirri?
I have become quite intrigued by this little Thursday afternoon wormy discussion. Would you be interested Geoff to send us a piece of tissue and we will sequence it for you? Assuming you have material in ethanol. Perhaps we should have a wager; I am sure Jim is right but it also reminds me of cirratulid/ctenodrilids, particularly Raricirrus, which we are working on a little bit. Please do pop some sample in the airmail if you like, we will post the genetic results here to this list for anyone to use.
Dr Adrian Glover, Natural History Museum
homepage<http://www.nhm.ac.uk/research-curation/staff-directory/zoology/a-glover/index.html> | publications<http://scholar.google.co.uk/citations?user=UAnD2y0AAAAJ&hl=en> | twitter<http://twitter.com/adrg1>
+44 20 7942 5056 (tel.) +44 7766 648 440 (mob.) adrianglover_mac (skype)
On 2 Feb 2012, at 15:16, James Blake wrote:
I realize I had not sent this to the entire list.
---------- Forwarded message ----------
From: James Blake <jablake9 from gmail.com<mailto:jablake9 from gmail.com>>
Date: Thu, Feb 2, 2012 at 8:23 AM
Subject: Re: [Annelida] RE: Oligochaete with anal cirri?
To: Geoff Read <Geoffrey.Read from niwa.co.nz<mailto:Geoffrey.Read from niwa.co.nz>>
This is a paraonid.
There is an entirely unreported group of offshore paraonids that have a type of crotchet or hooked neuroseta. Sometimes it appears bidentate owing to an overhanging sheeth. There are a fair number of species, some quite common in deep water. All are small and typically only retained on very fine mesh sieves; most have anywhere from 3-12 pairs of branchiae, but at least one abranchiate species is known to me, yours appears to be another.
We have tentatively placed these in the genus Levinsenia. All are new to science.
On Thu, Feb 2, 2012 at 12:34 AM, Geoff Read <Geoffrey.Read from niwa.co.nz<mailto:Geoffrey.Read from niwa.co.nz>> wrote:
And here is a couple of small images, one of either end. Magnification x200 or so.
> -----Original Message-----
> From: annelida-bounces from oat.bio.indiana.edu<mailto:annelida-bounces from oat.bio.indiana.edu> [mailto:annelida-<mailto:annelida->
> bounces from oat.bio.indiana.edu<mailto:bounces from oat.bio.indiana.edu>] On Behalf Of Geoff Read
> Sent: Thursday, 2 February 2012 2:58 p.m.
> To: Polychaete mailing list
> Subject: [Annelida] Oligochaete with anal cirri?
> Dear all,
> Quick question? Do oligochaetes ever have a pair of anal cirri? I have been
> looking at offshore samples from mobile coarse sands with some interesting
> small worms in them, and there is this apparent oligochaete (or not) which has a
> lovely pair of delicate anal cirri. It has a long prostomium, or perhaps it's the
> pygidium if I've oriented it wrong way round (it's hard to say), is exceedingly thin
> (0.15 mm w, & TL 10 mm) like a marine oligochaete, has mixed capillaries and
> slightly thicker shorter unifid S-shaped single chaetae. What do you reckon it
> could be if not an oligochaete? There are no tentacles along the body (as in
> cirratulids and affiliates). There is a polygordiid genus which has chaetae, but
> apparently not along the whole body as this worm has.
> Thanks in advance for your ideas to enlighten me.
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