Diurodrilids have a prostomium that lacks appendages and
bears two transverse restrictions, a peristomium, five
indistinct trunk segments and a pygidium. The
prostomium lacks antennae and all other appendages. A
ventral pharyngeal muscle bulb is present, as is a
prepharyngeal gland anterior and two salivary (oesophageal)
glands posterior to the pharynx. Jaws are absent. Parapodia
and chaetae are absent; the only appendages are two, typically
forked, pygidial ‘toes’ with adhesive glands and muscles. The
body is covered by a cuticle which in some species is
regionally thickened, forming clear patterns of plates that are
species-specific. Ciliation is present as sparse
patches, transverse rows or sensoria; ciliophores, specialised
ciliated areas arranged in species-specific patterns, are also
present.
The above description is based on Paxton (2000)..
Identification tips
Recognising the family
Diurodrilidae are minute, interstitial polychaetes which can be recognised by the grub-shaped body combined with a pygidium which comprises multiple digitate lobes.
Distinguishing species
Species may be distinguished by the development of the cuticle which in some species is regionally thickened forming plates, the patterns of which are species specific.
