dejayM's picture

Scale Worm - Harmothoë imbricata

Observed: 8th October 2013 By: dejayM
Biological Recording In ScotlandHighland Biological Recording GroupOrkney Biodiversity Records Centre
dejayM’s reputation in InvertebratesdejayM’s reputation in InvertebratesdejayM’s reputation in InvertebratesdejayM’s reputation in Invertebrates
single scale
mouth under

Found under stones in the mid to low water zone, but may be found quite a bit higher.
Apparently black but close inspection of scales reveals it to be grey, though deep brown in strong lighting.
See comments

Species interactions

No interactions present.


dejayM's picture


Origin Oct 2013 - edit corrected H'link
This has been a difficult task (for me) - separating out imbricata from one or two others.
Certainly there are very few Harmothoë which appear to be black, yet 2, perhaps 3, other postings in iSpot
show this form.
Blackness seems to come from the area of overlapping (imbricated) dark grey scales - giving a very dark central zone for most of its length. I find it interesting that the scale was almost transparent for nearly half its width.
Keying out properly, using Fish & Fish for a change, it comes down to H.imbricata and H.impar.
The latter has been dealt with, I think pretty satisfactorily, here
So this leaves H.imbricata. Leaning a little on Ruth Barnich's** key I conclude, as well as I can, that it fits reasonably well.

Fun with photography. The worm was quite a character in captivity, squirming, highly mobile and pretty resistant to manipulation.
Two (only) pictures are through the low power microscope, the camera simply held to the eyepiece. It is worth looking at the original of P6 because it is an enlargement (compact Lumix LX7), not a micropic. In any case, this view of the mouth and oesophagus is very rare.
The single scale was prised from the back and in doing so I almost certainly damaged the edges (if not the animal) which should show a fringed margin. Close inspection of the scales on the animal (picture 3) shows these 'papillae' to be present.

Joe Botting's picture

Good job, Derek

I'm impressed. It is really good to see you getting to grips with these, and that's a very useful discussion of the species concerned.

I'm also impressed how the ispot pages themselves are starting to become a really useful resource, when combined as you've done here. We might have to think about pulling some of these together into a reference area, if that's possible...

dejayM's picture


Well Joe, that's nice, very nice (and thanks, really). I am an advocate for quality posts and I am old enough to know what that might mean.
However we must not get carried away with POOS (posts of obscure subjects), as we well know there is nothing more likely to put off the very people we (you) hope to inspire.
Look forward, though, to more poos from me!

JoC's picture

Harmothoë imbricata

I have read all your notes, the notes on the other ispot posts you cite (and will agree some of those next), Ruth's key (quite a task!), checked H & R 1990 (which means the 2 vol set) and find your id to be absolutely correct.

POOS are good - there are plenty of ispot posts where few if any id features are given. For the less obvious (i.e. obscure) entities this level of detail can only add to the body of scientific knowledge. As as result of just this post I now know more about the head end of annelids than I thought it possible to know. Joe Botting's comment on your post is absolutely right.


nightfly's picture

Hi Derek, Just saw your

Hi Derek,

Just saw your linked pdf on scaleworms. I must put that to use as some years ago I photographed 2 different coloured scaleworms from the same low tide location. One was amber, the other was very dark with white edging(legs) as above.

TBC, that pdf should give some clues as to their species.


dejayM's picture


It's nice to see you here Cathal (might you agree with the ID?). You'd do well to follow Jo. (JoC) She has a precise, inquisitive and scientific style.
I put a lot of work into this particular post and I found Ruth Barnich's paper extremely useful. I could easily specialise in scale worms - but prefer to be a broad Naturalist - flitting? no-one else seems interested!
Good wishes.

nightfly's picture

Hi Derek, I'll have to look

Hi Derek,

I'll have to look at them a bit, ie follow your research. I have pics of the same scaleworm beside a monotone amber one. I dont know if they are the same species or not but they were found under the same few stones at a low tide spot. When looked at underneath, they are very similar in structure to ragworm, just a lot shorter.


Leslie Harris's picture

color variations

there's a very nice paper by Nygren et al 2011 on color polymorphism in Harmothoe imbricata Unfortunately it's not open access but if you google "Harmothoe imbricata polymorphism" you'll get the color plate from the paper. It shows 10 different color variations which were shown via DNA to all be the same species. There's quite a range of pigment patterns. This bluish-black form is the first in the plate.

dejayM's picture


Origin 9pm
Thanks Leslie. you are right and right. First, that Type A in the Illustration is what we have here and second, I cannot access the document for less that £31!
Beyond that, it is satisfaction indeed that the three (of the five or so) most useful people in iSpot have agreed - why? Well because it is what it says on the tin and, now I look back (I had forgotten), it is a nice persuasive piece of work - I wish all my posts were so! This - (suffusion)?
I just love your new Badge! (awarded via ZA?)
PS (later)
Santa never visits anywhere in April! It is very likely that your short Polychaetous foray into Southern African iSpot generated the Expert status - they are MUCH more progressive there.
I dropped a mail on you last week at your *** address. Mine is dejay.project at

Leslie Harris's picture


Send me a PM (can we do that here?) with your email if you'd like to have the article. I'd be much more useful if you were submitting photos from my neck of the woods. :^D No idea how I got the badge.... maybe Santa showed up early?

I'll go wander over to your suffusion post, see if I can add to the confusion.