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Tomopteridae
Description
The prostomium and peristomium are fused to the first
segment. A pair of ventral tentacular cirri (which may be
absent in some species or in adults) is located on the second
segment). Antennae are absent, and one pair of
large tapering unarticulated ventral palps is present. The
nuchal organs form a pair of dorsal crests. A short eversible
muscular pharynx is present, but terminal papillae and jaws
are lacking. Segment 2 is the first visible segment; it bears one
pair of posteriorly directed tentacular cirri which may be as
long as the entire worm and is supported internally by rigid
acicula. External chaetae are lacking. Parapodia are biramous
with foliose notopodial and neuropodial lobes; some authors
refer to these as dorsal and ventral cirri, but dorsal and ventral
cirri are lacking according to Fauchald & Rouse (1997), as are
branchiae and pygidial cirri. The posterior region may be
modified into an elongate tail.
The above description is taken from Wilson (2000), which follows that of
Fauchald & Rouse (1997).
Identification tips
Recognising the family
Tomopterids are transparent planktonic polychaetes; they have a long pair of rigid
tentacular cirri originating on the first visible segment which will distinguish them from other polychaetes.
Distinguishing species
Characters used to distinguish species include the form and length of the nuchal organs (crests
which extend from the tentacles to the eyes and ventrally) and
the form of parapodia and parapodial glands.
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Identification tips |
Natural History |
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References |
Identification guide
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