Guide to New Zealand Shore Polychaetes

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"Under the sand at low tide are whispers, hisses, long slithers, bubbles, the suck of ingestion, a soft snap ..." (Fleur Adcock)

Polychaetes, segmented bristle-bearing worms of class Polychaeta in phylum Annelida, are usually the most abundant animals living within sands and muds on the seashore. These worms cannot often be seen on the surface but sometimes they may create subtle signs and traces of their presence. Only a few may be found exposed on bare rock surfaces, but they are common cryptic animals within rock crevices on the seashore and under boulders. Those that can survive the harsh environmental conditions on top of rock usually live in colonies, protected inside tubes.

This guide provides help for the identification of many polychaetes of rock and sand shores of New Zealand. It is also a source of reference for what is known about them. It covers many common species living in the intertidal in sediments on harbour beaches, estuarine flats, and open beaches and on or in the rocks of beaches. Eventually we hope to have information available on many other New Zealand polychaetes. Common species that are not covered here yet are those that are subtidal (including those of permanent rock pools), and those that are epifaunal or live in algal turfs.

Rock channel at Moa Point, Wellington south coast

New Zealand polychaetes

  Rocky and sandy shore habitats and polychaetes
  About polychaete identification
  About species names, classification, and nomenclature
  New Zealand polychaete species list and reference lists
  References to introduction


Rocky and sandy shore habitats and polychaetes

A rocky shore is a tough place to live. It heats up and dries when the tide is out, and is subjected to tremendous forces of wave pounding in onshore storms. Soft-bodied, delicate polychaetes are not the ideal organisms to survive there. And yet many do, but they live mostly hidden away. Even on hard volcanic basalt there will be a few cracks, and on other rock types cracks and crevices are everywhere. These are suitable homes for polychaetes. Then in the lower intertidal and in pools there are algal holdfasts and turfs of coralline algae which teem with polychaetes. These are specialist habitats and their fauna is too diverse and little-known to include here at present.

The alternative to finding a suitable crevice to live in is to build a protective structure on the rock. This is the strategy of a few polychaetes - the sabellariids which build colonial mounds of thousands of sand-grain tubes cemented together, and the serpulids which always live inside hard calcareous tubes as individuals and sometimes aggregate into colonies.

Surf beach at Porangahau Beach, north of Cape Turnagain, North Island Soft shores are where polychaetes flourish, especially in the sheltered waters of estuaries and harbours where the sediment is most stable and permanent burrows are possible. There are fewer polychaete species on exposed surf beaches where the sand is on the move constantly, but some specialist species thrive in these conditions.

There are also mixed shores where rock and sand faunas mingle — rocky shores with patches of sand behind, or sand-lined rock pools, and soft shores with rock patches or stones and shell drift overlying sand and mud.

NZ shore polychaetes. Identify family group OR Browse families by group

About Polychaete identification

Polychaetes are generally regarded as difficult to identify because they are rarely intact, their bodies may distort during sample processing, and the families are so diverse in morphology. However, this extreme diversity can also be a help. While identification to family by attempting to work solely through a text key is probably destined to frustration and failure because the terminology can be overwhelming, one of the best ways to identify the family in which a worm belongs remains the simple process of looking at published pictures and attempting to find a match to its general appearance. This is largely the solution adopted here, although a character-by-character key to polychaete families using the precise terminology of taxonomy will be necessary sometimes.

The greatest barrier to identifying New Zealand worms to species is the lack of easily accessible information. This guide, like other efforts worldwide, is a response to an awareness "that ecologists and students have problems in gaining access to specialised literature and also in comprehending them ..." (Hutchings 1999:388). Taxonomic specialists take years to accumulate copies of old publications, and it is extremely helpful to everybody to gather and condense this scattered information into one resource online. The next greatest problem is that a lot of New Zealand species are still undescribed or were poorly described in the original publications. There is not much that can be done about that immediately, but gradually, as revisions of species groups take place, the state of knowledge will improve. While overall knowledge is still inadequate, it is important that surveys should identify to species whenever possible.

Further background information can be found in the books "Polychaetes and Allies" and "Polychaetes". Also the 2 volume set "Polychaeta of Southern Africa" remains a classic reference, and "The Polychaete worms Definitions and keys to the Orders, Families and Genera", is still most useful. These books are available in university libraries. In addition "POLYCHAETES An Interactive Identification Guide" is a CD-Rom containing an interactive key to all families and genera and is available at CSIRO publishing. The web site summarises such resources. Glasby and Read (1998) have recorded the history of polychaete taxonomy in New Zealand. Much of the early descriptive work was done by European-based naturalists in the late 1800s to early 1900s and published, not in English, in what today are very obscure scientific journals.

Terminology used in polychaete taxonomy can be looked up in a glossary of polychaete terminology (local copy courtesy Glasby and Fauchald). There is an online interactive key by Glasby and Fauchald to all polychaete families of the world which runs using DELTA Intkey software (available for download). This key can be entered using any morphological character, and has explanatory text, images of morphology, and whole worm images.

Use online key at ABRS site

NZ shore polychaetes. Identify family group OR Browse families by group

About species names, classification, and nomenclature

A species name is intended to be a unique label for an organism so that we are able to talk together with confidence about its biology knowing we are discussing the same entity. It comprises a generic name (the genus) placing the organism with similar ones, and a specific name (the epithet). This two-part identifier system is both very useful and a source of problems. The problems come about because the two-part species name contains an inbuilt subjective classification, the bottom-level of the Linnaean hierarchical classsification. This is a flawed system trying to represent two concepts that may mesh together poorly - the degree of differentness of groups of organisms, and their phylogenetic relationships (what evolved from what). The genus, family, order, class system is an artificial construct. We are stuck with it, but please don't regard it as holy writ.

A researcher may decide to 'move' the species to another genus, prompting confusion because the species name has 'changed'. Non-taxonomists tend to get upset and confused by this, and some taxonomists appear to delight in their power to make these minor changes. It is important to understand that the original name combination first given to a species is (with rare exceptions) unique, stable, and of value for all time, whereas all subsequent generic changes are merely assertions of opinion which taxonomic freedom allows us to 'believe it, or not'. The original name links the published description to the type - the original specimen held in long-term storage in a natural history collection somewhere. The type specimen is the ultimate determiner of the name, hence the great importance of type-holding museums for science. This system of naming is today controlled by a code of laws, the International code of zoological nomenclature, which taxonomists of earlier days didn't have. They probably didn't designate types, and also time and world events may mean their specimens equivalent to types have been lost, while the names they used live on in print, sometimes represented only by sketchy descriptions, and thus of doubtful value. We cannot ignore these names, so they sit in lists of species alongside all others, but unfortunately it may be that we can have no certainty what they were referring to. Original names (basionyms)and sources for New Zealand polychaete species, and an evaluation of the original content are included in this guide.

NZ shore polychaetes. Identify family group OR Browse families by group

New Zealand polychaete species list and reference lists

Amongst the earlier taxonomic literature for New Zealand the works of Ehlers and Augener in the 1900s stand out as the most substantial, and are the most useful to obtain first, with Ehlers describing many intertidal species and Augener the subtidal material collected by Mortensen (see lists for dates and citations). Schmarda contributed his monograph four decades earlier in 1861, and leaves a legacy of many species names, but his brief descriptions are often problematic. Nevertheless his names are in current use for some common species. Glasby and Read (1998) analyse historical polychaetology in New Zealand in detail.

References to introduction

Beesley, P. L.; G. B. Ross; C. J. Glasby. (2000). Polychaetes & Allies: The Southern Synthesis. Fauna of Australia. Vol. 4A Polychaeta, Myzostomida, Pogonophora, Echiura, Sipuncula, Fauna of Australia. Melbourne, CSIRO Publishing. xii 465 p.

Day, J. H. (1967). A monograph on the Polychaeta of Southern Africa. British Museum (Nat. Hist.) Publication. British Museum, London. 878 p.

Fauchald, K. 1977. The Polychaete worms. Definitions and keys to the orders, families and genera. - Natural History Museum of Los Angeles County, Science Series 28:1-188.

Glasby, C.J.; Read, G.B. (1998). A chronological review of polychaete taxonomy in New Zealand. Journal of the Royal Society of New Zealand 28(3): 347-374.

Hutchings, P. (1999). Taxonomy of estuarine invertebrates in Australia. Australian Journal of Ecology 24(4):381-394.

International Commission on Zoological Nomenclature. (1999). International code of zoological nomenclature. Fourth edition. The International Trust for Zoological Nomenclature, London. 306 p.

Rouse, G. W.; F. Pleijel. (2001). Polychaetes. Oxford University Press, Oxford. 354 p.

Wilson, R. S.; PA Hutchings, P. A.; Glasby, C. J. (eds) 2003. Polychaetes: An Interactive Identification Guide. CSIRO Publishing, Melbourne.


Compiled by Geoffrey B. Read (comment and error reports welcome). Original content copyright © 2004 NIWA.

The text for each Polychaeta Family Page includes in adapted and revised form much material written by G. Read for the unpublished NZ Coastal Marine Invertebrates guide, a project led by and edited by Steve Cook.

The style and layout of each Polychaeta Species Page were inspired by the species summaries in FishBase (2000 version) global information system on fishes.

This work was funded by the New Zealand Foundation for Research, Science and Technology (FRST) as part of FRST contract C01X0219, Biodiversity of New Zealand Aquatic Environments, to NIWA, National Institute of Water & Atmospheric Research, New Zealand.

The information found in this guide may be cited for publication or used for public education material.
Please fully acknowledge re-use or quote. The recommended citation for the shore polychaete guide is as follows:

Read, G. B. (compiler) 2004. Guide to New Zealand Shore Polychaetes. Web publication. <> Date of access dd-mmm-yyyy

NZ shore polychaetes. Identify family group OR Browse families by group