Eunicida is an order of polychaete worms.
Characteristics
Members of this order have an elongated,
segmented body and a distinct head, normally with a separate
peristomium and
prostomium. Many, but not all, live in
Tube worm which vary from a
Mucus sheath to a tough,
Keratin casing. The
palps vary from globular to cylindrical and there are from 0 to 7 antennae, usually smooth but occasionally jointed. There is a muscular
pharynx with a dorsal pair of
and a set of ventral, toothed, maxillary plates. Some species have tentacular cirri and all have unbranched
Parapodium. In some species, dorsal cirri, branchiae, ventral cirri and chaetae occur, but not in others.
[ Eunicida Natural History Museum. Retrieved 2012-01-17.]
Fossil record
The
Devonian Websteroprion is the largest known fossil eunicidan annelid, with estimated length .
It also had the biggest
of any prehistoric
polychaete, up to in length and possibly larger.
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Families
The World Register of Marine Species (WoRMS) includes the following families in the order:[
]
