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Related Articles: Featherduster Worms, Worm Diversity,

/The Conscientious Marine Aquarist

Bristleworms, Fireworms & More: Errantiate Polychaete Worm Diversity

To: Featherduster, Sedentariate Polychaete Worms

By Bob Fenner


By some estimates there are more species of "worms" than insects! Most of the large groups, the phyla of Roundworms (Nematoda), Flatworms (Platyhelminthes) and Segmented Worms (Annelida) are barely known to most of us. The very common and important other "wormy" groups are virtually unknown. We use these organisms consciously as food, to help keep our substrates from compacting and channeling, as filter-feeding "cleaners" in marine reef systems and dook it out with them as disease carrying and causing parasites and competitors.

Why the lack of respect? What is this, another example of species-centricity? Worms are everywhere; in your hair, in the air, in the deepest seas, warmest waters, driest deserts... Doing everything: parasitic, free-living, filter-feeding planktivores, detritivores, ferocious predators, sneaky vacuum cleaners...

Yes, worms are wormy; often slimy, reclusive, mysteriously appearing and disappearing. But they were here first! All major and minor worm groups were on the planet in full force before the Cambrian. They are still critically functioning as aerators, facilitators of decomposition and general energy transfer/recycling and as store houses of food energy and webbing themselves. Let's use this brief article to discuss one phylum of worms often encountered on purpose and accident by marine hobbyists, Polychaete Annelidans:


In the world of zoological taxonomy feather dusters, duster-cluster, bristle, fire, fan, tube...worms are grouped/placed in the Annelida, generally known as the "segmented worms", in reference to their metamerism or segmented appearance.

This segmentation allows for different types of locomotion, several environments. External and internal segmentation is obvious in the body, parapodia (lateral processes), nervous, muscular, excretory and circulatory systems arranged in repetitive placement.

There are three living Classes:

1) Oligochaeta, meaning "few bristles", the ubiquitous "earthworms" that indeed do have small body bristles.

2) Hirudinea, the leeches. All basically parasitic.

The above two are mostly freshwater and terrestrial and differ generally in basic ways in terms of internal anatomy, having permanent gonads...unlike the

3) Polychaeta ("many bristles"), some are downright prickly, are mainly marine. They have a head end (prostomium) with a typical sensory array of tentacles, papillae, eyes... and a posterior segment (pygidium). New sections are added right before the pygidium. What else? longitudinal muscled bands effect motion through contracting against a fluid filled body cavity (coelom). The digestive tract is a more or less straight tube running from the anterior mouth to the posterior anus. Most do have a "closed" circulatory system, blood and a "heart", an anterior dorsal ganglionic mass (brain), lateral nerves in each segment, blah, blah, blah. And they're neat! Some are big (larger than your hand, longer than your fish. And here, fellow pet-fish commandos, I must confess to a certain period of intransigency when even I lived on the public largesse. For a couple of years in grad. school I did "environmental" work sorting and identifying benthic marine invertebrates, principally polychaete worms. My dear cubicle mate actually had a beautiful graphic of a Glycerid polychaete worm with double everted jaws (shades of Aliens I and II & III), multiple eyes and specialized parapodia with a blasphemous label "God is a Polychaete!

There are so many species of polychaetes occurring most everywhere in marine environments with known life "habits" that much can be discerned by collecting, i.d.ing, counting 'em up and measuring now and later to determine "impact" of human or other activity.

So yes, money can be made with life science degrees! My roomie used to do Errantiates and I'd get stuck with the Sedentariates. Hey, what are they!? Glad you asked; back to the story at hand:

Polychaetous Annelids are sub-divided into two sub-classes:

A) Errantia: Characteristics include numerous, similar segments, well-developed lateral processes (parapodia, acicula, setae). Have definitive "heads" with a pharynx with jaws or teeth. Include swimming (six pelagic families!), crawling, burrowing and tube-dwelling members. And, ahem, the group in question: Hermodice canunculata.

B) Sedentaria: Polychaetes that commonly display a high degree of segmental differentiation; parapodia reduced, without specialized acicula or setae, prostomium (head) without sensory structures but with tentacles and palps, other feeding structures. No teeth or jaws present! Several families including the two commonly included as the trade and hobbies fan and feather duster worms, the   i. Sabellidae with non-calcareous tubes  (Anamobaea onstedii at right, Cozumel pic).   ii. Serpulidae with calcareous tubes (Spirobranchus gigantea at right)

Errantiate Polychaetes (Bristle, Fire...) Worms... On Parade!

The vast majority of worms are good indeed... for keeping your substrates open, free of accumulating mulm, providing food for macro-eaters as well as filter feeders (their sex products)... Here is a side view through a healthy substrate.

Amphinomid... Fireworm of the family Amphinomidae. If it's not visually obvious where these worms get their common name, you'll understand if you handle them! The bristles attached to their noto- and neuropodia are sharp and hurt like no tomorrow to get stuck by. Ouch! This one out and about at night in N. Sulawesi.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.
Chloeia fusca McIntosh 1885. Family Amphinomidae). Indo-West Pacific; East Africa to Indonesia, Japan. On sandy, muddy bottoms, actively seeking prey. Positively phototropic. Note two dark dorsal bands. N. Sulawesi pic. 

Hermodice canunculata, a larger species of "Bristleworm". Large pleated structures (caruncle) on all segments denote this too common, out and about species in the tropical West Atlantic. Family Amphinomidae. Four to six inches total length. Often found feeding on gorgonians, anemones, hard corals. Close-up to show you part of the "fire", the sharp bristles that make up the podia on each segment of the body. Bahamas, Cancun and Cozumel images by day and Bonaire at night.. 
Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Family Eunicidae: Bobbit Worms!

Howsit? Yes, on Xmas, am going over pix...   12/25/12
Lynn... do you have any idea what this might be? Looks so much like a trap door spider opening... underwater! In Cozumel this last week. B
<Wow, I know I've seen one of these before, but can't remember what made it.  I'll get back to you as soon as I figure it out.  Take care, Lynn>
Oh, thank you... have a couple more pix of this/it... but all about the same. Cheers! B

Re: Howsit? Yes, on Xmas, am going over pix...   12/26/12
Hi Bob,
I think the webbing is part of a eunicid's lair.   When I see webs, the first thing I think of is a vermetid but in this case, the entire structure, combined with the associated threads, looks too intentionally shaped and anchored - like that of a funnel-web/trapdoor spider.  A vermetid’s would have been a lot messier and more random. 
I’ve heard about these webs, specifically from eunicids, but have never seen one in person.  It’s entirely possible that other Polychaetes build/live in such, but I just don’t know of them.  I looked through all my resources, and on the web, but with no luck.  I did, however, manage to find a couple of photos showing eunicid webbing, but one is small and hard to see detail and the other is detailed but shows a much smaller web example (in the sand, not anchored to nearby rocks).
 Small photo, 2nd one down, showing webbing across the back of the tank:
<Ah, I read the description as "a spider web" there>
Webbed lining w/some around perimeter:
 <Ah yes; we have a winner!>
Wish I could give you a concrete answer but unfortunately, a somewhat educated guess is all I can offer!
Take care,
<Thank you for yet another mysterious pic/organism solved. BobF>
Re: Howsit? Yes, on Xmas, am going over pix...   12/26/12
You're very welcome, Bob - it was a pleasure as always!

Family Terebellidae
: Spaghetti Worms. Surface deposit feeders

Loimia medusa (Savigny 1820), the Medusa or Spaghetti Worm. Cosmopolitan; all tropical seas. Found between rocks in silt to sandy substrates. Tube-dwelling (family Terebellidae) worm that is most often recognized by its extended feeding tentacles. Hawai'i image. 

Eupolymnia crassicornis (Schmarda, 1861), Spaghetti Worm.

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The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Here a group of Spaghetti Worms living in close proximity in Costa Rica (Pacific side), 2011.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

To: Featherduster, Sedentariate Polychaete Worms

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