[Annelida] Tiny fresh water worms

Ariel Chipman via annelida%40net.bio.net (by ariel.chipman from huji.ac.il)
Fri Nov 27 06:45:37 EST 2009


Dear All,

Many thanks to all the people who replied to my query and sent me  
additional material. Since the answers were all off-list, I will  
summarize for those curious to hear the outcome. There is a general  
consensus that these are members of the Aeolosomatidae, but difficult  
to identify beyond that. Several people have sent keys or references,  
and I will delve into these to see what I can conclude. The  
Aeolosomatidae are meiofaunal annelids, though there is little  
agreement in the literature about where they fit phylogenetically  
(Oligochaeta or Polychaeta). Their most distinctive feature is the  
presence of large red or orange epidermal glands.  These are clear in  
the worms I have, though not obvious in the monochrome image I sent.  
They reproduce asexually by paratomy, which would explain why they are  
suddenly so abundant in one culture.

If anyone is interested in this group, I can try to isolate some and  
send them.

Best,

Ariel



On 26 Nov 2009, at 15:13, Ariel Chipman wrote:

> Dear annelid enthusiasts,
>
> As a non-annelid specialist, I wonder if someone in this list can  
> help with identifying some very small worms that have invaded a  
> paramecium culture that I have been maintaining for teaching. The  
> culture is fresh water, but is far from clean, and includes input  
> from various different sources, so it is next to impossible to trace  
> where they came from. They are roughly a millimeter long, have  
> definite segments with chaetae, no obvious eyes, and no external  
> mouthparts. They are generally soft bodied and very flexible. A hard  
> pharynx is visible (but not obvious in the photos), and they seem to  
> be feeding on plant matter, rather than the Paramecia that surround  
> them (I infer this from green matter in their guts, and because I  
> think I saw them browsing on plant material, but never attacking a  
> Paramecium). I showed them to our local annelid expert, Nechama Ben- 
> Eliahu. She suspects they are archiannelids, but they don't fit in  
> with any of the keys she has. I attach two photos, which I have  
> scaled down for sending, but can provide higher resolution versions  
> (and more photos) if anyone is interested. One photo is lower  
> magnification and shows two individuals of slightly different sizes.  
> The second photo is a hihger magbnification of the head region, with  
> a Paramecium for scale.
>
> I would be happy for any help in identifying these critters.
>
> Cheers,
>
> Ariel
> <head region.jpg><two worms.jpg>
> +=+=+=+=+=+=+=+=+=+=+=+=+=+
> Dr. Ariel Chipman
> Senior Lecturer
> Academic Curator of Aquatic Invertebrates
> Dept. of Evolution, Systematics and Ecology	
> The Hebrew University of Jerusalem
> Givat Ram Campus
> Jerusalem 91904
> Israel
>
> Office phone: ++972-2-6585816
> Lab telefax:    ++972-2-6585809
> ariel.chipman from huji.ac.il
>
>
>
>
>
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