Ceratonereis singularis Treadwell, 1929

View scientific description and taxonomy

Scientific Details

Family level description.
Nereididae are polychaetes with many uniform segments, without strongly differentiated body regions. The prostomium (head) has one pair of antennae, one pair of articulated palps, and two pairs of eyes. Four pairs of unjointed cirri emerge from the next segment behind the prostomium. Mouthparts comprise an eversible pharynx with one pair of terminal jaws, although these are usually only visible by dissection.

Species level technical description.
Prostomium with anterior margin indented. Longest tentacular cirri extend back to chaetiger 15. Maxillary ring of pharynx with conical paragnaths: Area I paragnaths absent; II: 9-15; III 6-13; IV: 10-16. Oral ring paragnaths absent. Dorsal notopodial ligule not markedly elongate on posterior chaetigers. Not markedly broader on posterior chaetigers. Dorsal notopodial ligule not markedly reduced on posterior chaetigers. Prechaetal notopodial lobe absent. Dorsal cirrus not terminally attached to dorsal notopodial ligule on posterior chaetigers. Dorsal cirrus length about 1 times ventral notopodial ligule at chaetiger 10-20. Neuropodial postchaetal lobe present, at least on some anterior chaetigers. Ventral neuropodial ligule on posterior chaetigers reduced, up to half length of acicular neuropodial ligule. Ventral cirri single. Notopodial homogomph spinigers absent; sesquigomph spinigers present. Notopodial homogomph falcigers absent. Neuropodial dorsal fascicle fused falcigers absent.



General Description

In members of this genus the prostomium (head) is strongly indented between the antennae. The eversible pharynx has paragnaths, but only on the maxillary ring (closest to the jaws). This species can be distinguished from related species with care; the 3 species of Ceratonereis in southern Australia are not easy to tell apart. There are various differences in structure of the parapodia (feet) but the easiest to observe is the dorsal cirrus which in Ceratonereis australis is about 2 times as long as the parapodium; in Ceratonereis perkinsi it is 5-6 times as long as the parapodium; in Ceratonereis singularis the dorsal cirrus is about the same length as the parapodium. Body up to about 4 cm long.


Coastal bays and the continental shelf.

Soft substrates

Distribution guide

South-eastern Australia, south-western Australia, and north-western Australia.

Species Group

Worms Ragworms


Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

4 cm

Commercial Species


Global Dispersal

Recorded in Australia

Species Code

MoV 2583


Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed


article author Wilson, R.

Robin Wilson is a Senior Curator of marine invertebrates at Museum Victoria.


Cite this page as:
Wilson, R., 2011, Ragworm, Ceratonereis singularis, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 18 Jul 2024,

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