We reveal that a widespread marine worm species is actually several undescribed species, each known from restricted localities.

Amaeana brasiliensis
Light microscope image of holotype of Amaeana brasiliensis showing the characteristic bunch of buccal tentacles which have been lost in the lectotype of A. trilobata. Image: Orlemir Carrerette
© Orlemir Carrerette

Many worm species have been reported as occurring in many oceans and in a variety of habitats. Yet it seems unlikely that the same species can occur in both the tropics and the Arctic and in a range of depths. So how does this occur? Often because the original description and illustrations are so brief that anything vaguely like it is identified as that species. Through some detective work, we found that one species of seaworm thought to occur throughout the oceans is actually a group of species with much more restricted ranges.

The polychaete seaworm Amaeana trilobata was originally described from northern Norway as Polycirrus trilobata, but it has since been recorded from all around the world including tropical areas in Australia. This worm is also the type species of the genus and so it is very important to actually define it well. With the help of a Collection Manager at the Museum in Oslo, Norway we were able to locate specimens of this species Amaeana trilobata. We needed to be confident that Michael Sars had used this specimen to describe his new species- thankfully the locality corresponded with the place where Sars spent a couple of years as a Minister of Religion and the labels in the jar were written in his hand writing.

Amaeana trilobata.
Light microscope image of lectotype of Amaeana trilobata. Image: Orlemir Carrerette
© Orlemir Carrerette

These valuable worms were hand carried from Norway to the Australian Museum immediately prior to the 11th International Polychaete Conference by a colleague of the Norwegian Collection Manager. My colleagues and I examined carefully this old frail material and redescribed it. While we could not prepare any specimens for the Scanning Electron Microscope we used the state of art light microscopy techniques to illustrate the specimen.

Only once we had examined these specimens and defined the species which occurs in Norway were we able to be totally sure that it does not occur in Australia. Once we knew this, we were able to describe five new species of this genus from Australia, each with restricted distributions, as well as new species from Taiwan and Brazil. We would certainly bet that there are many other species of Amaeana waiting to be described which have previously been recorded as A. trilobata simply because we didn’t have a good idea of what true A. trilobata were!

Original drawing of Amaeana trilobata
Original drawing of Amaeana trilobata (1863) Sars from plate 25, figure 70 in Malmgren, A. J. (1865). Nordiska Hafs-Annulater. Ofversigt af Kongl. Vetenskaps-Akademiens Forhandlingar. pp.355-410. The description appears on page 392. Image: Fiona Simpson
© Australian Museum

As a result of this work, and our previous research, we suggest that any worm species which has been reported as having a wide distribution and present in many different types of habitat and was originally described in the late 19th century should be carefully checked. Our research also highlights the value of museum collections where material is deposited for posterity.

It is important to know our fauna, including our marine worms, otherwise we will not be able to document changes in species and in environmental health as a result of climatic and environmental change.

Dr Pat Hutchings
Senior Principal Research Scientist, AMRI

More information:
Nogueira, J.M.M, Carrette, O. & Hutchings, P. 2015. Review of Amaeana Hartman, 1959 (Annelida, Terebelliformia, Polycirridae) with descriptions of seven new species. Zootaxa, 3994: 1-52.