A cheat's guide to polychaetes

Updated

06/04/22
Read time

4 minutes

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Become an armchair expert with these key facts about polychaetes.

Polychaetes are multi-segmented annelids (worms) with parapodia (small leg-like structures) for locomotion and often with tentacles for feeding or branchial radioles for feeding and breathing.

The name ‘polychaete’ is derived from the Greek meaning ‘having much hair’ (referring to the chaetae or bristles found on many species).

Polychaetes are:

pronounced ‘polly-keets’
the most common benthic (bottom-dwelling) marine animals (both species and individuals)
mostly less than 10 centimetres long, but some species can reach 3 metres
found in estuaries, inshore waters, the open sea and the deep ocean.

The year of the polychaete

Do you remember where you were in 1983?

It was the year of the Ash Wednesday bushfires, David Bowies Serious Moonlight Australian tour and Bob Hawkes landslide election victory.
For a select few, however, it was the year of the inaugural International Polychaete Conference, when more than 90 biologists from 18 countries descended on the Australian Museum for a marine worm talkfest.
It was really exciting to be getting together with colleagues from all over the world for the first time and to focus specially on polychaetes, remembers Dr Pat Hutchings, a senior principal research scientist at the Museum.

Diversity

Pat is a systematist who describes, classifies and names the organisms we share the planet with. Back in 1983, the research techniques were pretty basic, just looking at species under a microscope and describing them.
Thirty years on, Pat has had no trouble convincing the organising committee to return to the Museum for the 11th triennial International Polychaete Conference (known as IPC2013).
Today we use the latest techniques in molecular biology and scanning electron microscopy (SEM) to work out where worms have come from and which groups they are related to – not an easy task given the limited fossil data for these soft-bodied animals.
Nearly 5000 new species of polychaetes have been described since the first conference – many of them by Pat and her colleagues at the Museum and other Australian institutions – doubling the number of known species to around 10,000 species today.
Increasingly we are finding that many widely distributed species actually represent suites of species, so the true diversity is even higher than that, Pat said.
Improved knowledge is not the only thing thats changed in the world of polychaete taxonomy – some of the students from the first conference are returning this year as senior scientists and even professors.
In the case of one of the plenary speakers, I taught him as a student to dive in China in the early 1980s, Pat said.
But a really exciting shift is that scientists are no longer just talking among themselves. This years conference has a whole program of events where were reaching out to people who need to know more about marine worms – which of course is everybody!

Polychaetes for the people!

The conference program includes a special evening where Australian Museum Members can find out more about polychaetes and meet the scientists [LINK].
Were also holding a workshop about how to identify invasive marine worms for nonspecialists like fisheries staff, quarantine officers and port authorities, Pat said.
Early detection is paramount because invasive worms transported by cargo ships, either as hull fouling organisms or in ballast water, have the potential to devastate our fisheries, aquaculture and tourism industries.
The workshop will use the new digital identification guide weve developed with financial support from the Australian Museum Foundation.
Therell even be a photographic display in the Museum Café highlighting the incredible colour, beauty and diversity of polychaetes.
Pat has lost none of her passion for polychaetes since 1983. People in government need to know that polychaetes are very important animals that provide essential ecological services, she said.
Some species process organic matter from the water or mud that would otherwise just accumulate. They convert this material into biomass to be consumed by fish and other predators. If it wasnt for polychaetes, our harbour would be a rotting, stinking mess.
Certain polychaetes are also sensitive biological indicators of pollution and we can tell how healthy a marine environment is just by seeing which species are present.

Program

This years conference shows just how slick and professional marine science has become. For early-career scientists and students, there are pre-conference workshops in photographing polychaetes and preparing material for SEM.
For taxonomy tragics, theres a one-week course in the Philosophy of Biological Systematics funded by the Australian Bureau of Resource Sciences and presented by another alumnus from the class of 83, Dr Kirk Fitzhugh from the Los Angeles County Museum.
Theres even a two-week taxonomy blitz at the Australian Museum Lizard Island Research Station to sample coral reef habitats and discover just which polychaete species are fuelling the reefs fragile ecosystem.
Most of the material collected and identified during the Lizard Island workshop will come to the Australian Museum, which has the largest worm database and collection in the world, Pat said.
Our understanding of polychaetes has certainly come a long way since I saw my first polychaete in the 1970s.
Weve been able to secure financial support for a number of students and early career researchers to attend this years conference, thanks to the Australian Museum and the CSIROs Wealth from Oceans Flagship.
It is incredibly pleasing to see a new generation becoming interested in this fascinating group of animals and to be able to inspire some non-scientists with polychaetes!
And thirty years on, David Bowie is back in the charts and another Federal election looms.