PORT PHILLIP BAY


Ragworm 

Nereis cockburnensis Augener, 1913

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 entire anterior margin. Maxillary ring of pharynx with Area I bare; II: 0-2 conical paragnaths; II: 4-13; III: 1-7; IV: 6-32. Area V: 0-19; VI: 2-7; VII-VIII: 60 or more; in a band 5-12 rows deep ventrally, 2-4 laterally. Dorsal notopodial ligule not markedly elongate on posterior chaetigers. Not markedly broader on posterior chaetigers. Dorsal notopodial ligule 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 absent. Ventral neuropodial ligule on posterior chaetigers similar to length of acicular neuropodial ligule. Ventral cirri single. Notopodial homogomph spinigers present. Notopodial homogomph falcigers present; first present at chaetiger 3. Notopodial homogomph falcigers articulated throughout. Notopodial homogomph falcigers multidentate, with 2 or more small lateral teeth, first and subsequent lateral teeth much smaller than terminal tooth. Neuropodial dorsal fascicle fused falcigers absent.

Taxonomy

Phylum:
Annelida
Class:
Polychaeta
Order:
Phyllodocida
Family:
Nereididae
Genus:
Nereis
Species:
cockburnensis

General Description

In members of this genus there are short-bladed chaetae with a distinctive ball-and-socket articulation present in the dorsal buch of chaetae on most segments starting at about 12-15 (these are referred to as "homogomph falcigers" in technical diagnoses). Paragnaths are present, usually on both rings of the eversible phayrnx. This species can be distinguished since only two local Nereis species have paragnaths present on Area V and have multidentate short bladed chaetae in the dorsal bundle of each foot. In Nereis cockburnensis the short bladed chaetae are first present on chaetiger 3, whereas in Nereis jacksoni they do not appear until chaetiger 10 or later. Body up to about 3 cm long.

Habitat

Collected from a wide variety of habitats, intertidal to depth of 20 m, occasionally as deep as 80 m.

Seagrass meadows

Soft substrates

Distribution guide

South-eastern Australia, or south-western Australia.

Species Group

Worms › Ragworms

Depth

Shore (0-1 m)
Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

3 cm

Commercial Species

No

Species Code

MoV 1100

Identify

Conservation Status

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

Author

article author Wilson, R.

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

citation

Cite this page as:
Wilson, R., 2011, Ragworm, Nereis cockburnensis, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 17 Nov 2019, http://portphillipmarinelife.net.au:8098/species/7551

Text: creative commons cc by licence