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Related Articles: Featherduster Worms: Natural History and Husbandry by Bob Fenner, Polychaete Worms, Worm Diversity, Nematodes: Roundworms

/A Diversity of Aquatic Life

Feather Dusters, Tube-Dwelling Sedentariate Polychaete Worm Diversity, part I

Sedentariate Polychaetes part II, part III, part IV

To: Errantiate (i.e. Non-tubiculous) Polychaetes (many known to hobbyists as "Bristleworms"

By Bob Fenner

Spirobranchus giganteus

"What is that thing? That biological dusting fan? A worm!?"

By some estimates there may be 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:

A Hawaiian species

Sabella sp. at a wholesalers

Spirobranchus on Porites Coral (Bisma Rock


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)

Sedentariate Polychaetes/Featherduster Worms... On Parade!

Family Sabellaridae: Make tubes of sand and shell fragments; are filter feeders and detritivores. Have a bristle made operculum to close over the opening, feeding tentacles and a pair of palps on the head.

Lygdamis sp. Honeycomb Worm. To 4 cm., 1.5". Nocturnal feeders. Circumtropical. Bali 2014

Family Sabellidae: Fanworms. Non-calcareous tubes produced that they live in, feed from. Filter feeders who retract their tentacular crowns when alerted. Often found attached to dead coral, or in sediment with part of tube exposed. Collected most often in "polluted" harbors in mud/muck. Includes genera: Bispira, Sabellastarte,

Typical Sabellid habitat... in the mud/muck... Many aquarists don't have similar environments (!) to house their Featherdusters... high nutrient, plankton levels... Another reason why these animals are best placed in "old" well-established systems, with ooze about, refugium sumps... This Bispira sp. in N. Sulawesi. 

Genus Anamobaea:

Anamobaea sp. Ghost Feather Duster Worms. 3/4" diameter heads. Centers of pale brown and three rings of light purple bands. Parchment tubes found in clusters in shallow sand.  Roatan 2016.

Bigger PIX:
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Anamobaea orstedii, the Split-Crown Feather Duster, family Sabellidae. Radioles in a radial arrangement, bilaterally symmetrically marked. Soft tubes generally unexposed. Found solitary or in small groups.  Belize and Bonaire pix.

Verticals (Full/Cover Page Sizes Available)
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Genus Bispira:

Bispira brunnea, Social Feather Duster Worms, Family Sabellidae. Come in whites, pink, purple and brown-banded varieties/colors. Groups in the Bahamas and Cozumel. 

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Verticals (Full/Cover Page Sizes Available) Linked
Bispira melanostigma, Variegated Feather Duster Worms, Family Sabellidae. Tropical west Atlantic. To 1 1/2" in size. Parchment tubes usually hidden below grade, in which they rapidly retreat if disturbed. Circular set of radioles, at times radially marked; eyes visible with good resolution. Roatan 2019.

Bispira variegata, Variegated Feather Duster Worms, Family Sabellidae. Tropical west Atlantic. 3/4- 1 1/2" in size. Parchment tubes usually hidden below grade, in which they rapidly retreat if disturbed. Here in the sand in Bonaire.

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Genus Megalomma:

Megalomma sp., Shy Feather Duster. To 1 in. Distinctive V-shaped fold in radioles. Occur in shades of brown and white.  St. Thomas 2014
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Sedentariate Polychaetes part II, part III, part IV

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