Tomopteridae is a family of holopelagic
polychaete
Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...
s belonging to the order
Phyllodocida
Phyllodocida is an order of polychaete worms in the subclass Aciculata. These worms are mostly marine, though some are found in brackish water. Most are active benthic creatures, moving over the surface or burrowing in sediments, or living in cr ...
. The genus Tomopteris consist of about 70 species, and the three other genera of one known species each.
Length varies from just 1-2 cm to 30 cm. These are very active swimmers, and have some of the highest metabolic rate among annelids. To increase buoyancy they have a large body cavity (coelom) filled with body fluid of a density similar to seawater. With the coelom taking up much of the inner space, the muscular system has been reduced to a mesh just below the epidermis. The circulatory system has been lost, and the coelomic fluid has taken over the role of transporting oxygen, nutrients and gametes. Instead of a heart the inner surface of the worm is covered with cilia that moves the fluid around inside the body. The absence of septa between the segments makes the circulation more efficient. A series of extretory organs called
metanephridia
The nephridium (: nephridia) is an invertebrate organ, found in pairs and performing a function similar to the vertebrate kidneys (which originated from the chordate nephridia). Nephridia remove metabolic wastes from an animal's body. Nephridia co ...
consists of ciliated funnels which opens to the coleomic cavity and connects with the exterior though a
nephridiopore A nephridiopore is part of the nephridium, an excretory organ found in many organisms, such as flatworms and annelids. Polychaetes typically release their gametes into the water column using nephridiopores.
Nephridia are homologous to nephrons ...
. Some species are bioluminescent, and produce a yellow light.
Their sperm differ from other annelids in having two tails. Females produce gelatinous egg cases that floats in the water column.
The animals use a type of propulsion called metachronal paddling, a sequential movement of multiple appendages. It is also able to change the surface area of each parapodia by spreading and contracting its two fleshy ends, which creates differences in drag between power and recovery strokes.
Swimming mechanics of the gossamer worm revealed
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Genera:Tomopteris
The gossamer worm (''Tomopteris'', Neo-Latin from Greek meaning "a cut" + "wing" but taken to mean "fin") is a genus of marine planktonic polychaetes.
All described species are known to be holoplanktic, meaning that they spend their entire life ...
'' Eschscholtz, 1825
References
{{Taxonbar, from=Q3897245
Errantia
Annelid families