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Biodiversity - Cirratulid polychaetes

This project will generate new knowledge about the very diverse and common, but poorly known cirratulid polychaetes. Therefore, we will assess the actual diversity and systematics of this group and its distribution. By covering virtually all Norwegian waters using the extensive museum collections, especially the Norwegian ones, we will greatly improve the knowledge of the taxonomy and distribution of the species involved.

Picture of a marine worm in front of black background.

Picture of a species of the genus Aphelochaeta.

About the project

Annelida, or segmented worms, is a vast and diverse group of metazoans that includes, amongst others, earthworms, leeches, echiurids, sipunculids and polychaetes. With around 20000 species known, they are a very diverse group and one of the main components of the marine communities. Within Annelida, the family Cirratulidae is common and abundant from shallow to abyssal marine benthic environments. It is a diverse family with around 360 described species belonging to 16 genera. Cirratulids are small worms, usually less than 3 cm long, characterized by the long, slender filamentous branchiae present all over their bodies and their anterior tentacles present either as numerous long filaments or a pair of thick appendages. While important in environmental monitoring, cirratulids are known to be taxonomically challenging and difficult to identify. Moreover, the validity of several genera has been questioned. Additionally, a recent survey of the genus Chaetozone revealed a high amount of cryptic diversity, but only a fraction of this diversity has been described. For Norway, 23 species are known, plus an additional 7 possible ones.However, records of several species, whose type locality is not European are suspicious, as cirratulids often have small distribution area. These records should be re-examined as they can indicate the presence of local undescribed species or translocations.

Another picture of a cirratulid worm.
Picture of Tharyx killariensis.

As specimens are rarely identified to species, the actual diversity in Norway is unknown, as are species distributions and their habitats. In the recent Artsdatabanken project “Polychaetes in Norwegian Port”, out of 11 cirratulid species morphologically identified, only six could be given a name. Moreover, COI barcoding revealed the presence of 15 species, showing the presence of even more undescribed and possibly cryptic diversity. Preliminary studies on both DNA and morphology have revealed even more undescribed species in Norwegian waters. This is particularly striking in deep environments, where up to 20 new species could be present. These preliminary studies have also revealed morphological differences between species, which can enable us to identify most of them. However, further studies are needed to properly assess species diversity as well as each species’ morphology and distribution.

Pictures of different samples in wet collections.

This is where the scientific collections of Natural History Museums come to our project. These hold an immense wealth of resources and information that is too often unexploited, and should be particularly valued in the current context of biodiversity loss. In Norway, the four main University museums gather a great many polychaete specimens from historical and recent collections. Hundreds of unidentified Cirratulidae are present in these museums from all Norwegian waters from the coast, shelf, offshore, slope and deep waters. This material is particularly suited to review the diversity and distribution of this poorly known species group.

Thus far, 17 species in 8 genera have been named, while 46 species in 5 genera still need to be named. While some are new species, for others the name needs to be confirmed by comparing them morphologically and molecularly with foreign specimens. Sequences of COI, 16S and 28S have been generated belonging to 60 species. These are valuable in the species delineation and taxonomic revision of the family. About 550 specimens have been sequenced. Specimens come from the whole Norwegian coast, Oslofjord, Trondheimsfjord and the areas around Bergen and Tromsø are particularly well sampled. Other well sampled areas include notably Sognefjord and Svalbard. Offshore areas include most of the slope of the continental shelf in the Norwegian Sea and parts of the shelf itself, part of the Barents Sea, parts of the deep sea around Jan Mayen, a vent side on the mid-Atlantic ridge and parts of the North Sea related to the oil fields.

You can also find some information on the project side at ArtsDatabanken.no (in Norwegian)

 

Publications

  • Grosse, Maël; Nygren, Arne & Capa, María (2026). Revision of some coastal species of bitentaculate Cirratulidae (Annelida, Cirratulida) from the North-East Atlantic. European Journal of Taxonomy. 1076(1), p. 1–46. doi: 10.5852/ejt.2026.1076.3304. Full text in Research Archive
  • Grosse, Maël; Nygren, Arne; Meißner, Karin; Struck, Torsten H; Kongsrud, Jon Anders & Alvestad, Tom [Show all 9 contributors for this article] (2025). Molecular Investigation of the Diversity of Cirratulidae (Annelida) Doubles the Number of Known Species in European Waters. Zoologica Scripta. ISSN 0300-3256. 54(5), p. 672–683. doi: 10.1111/zsc.12729. Full text in Research Archive

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  • Struck, Torsten H (2025). Yet another Artsdatabanken project successfully finished. doi: https:/blog.annelida.de/2025/09/30/yet-another-project-finished/. Full text in Research Archive
  • Struck, Torsten H (2025). The unknown biodiversity of annelids in European waters – a cirratulid case study. doi: https:/blog.annelida.de/2025/08/12/biodiversity-cirratulid/. Full text in Research Archive
  • Franz, Ole Hinnerck; Masaki, Hosea; Schneider, Yannik Karl Heinz & Rämä, Teppo (2025). Fleming on steroids - high-throughput co-cultivation assay for natural product discovery pipelines. Full text in Research Archive
  • Struck, Torsten H (2024). CEG with an even stronger commitment to Norwegian Biosystematics – Blogs of the CEG research group. doi: https:/blog.annelida.de/2024/11/05/ceg-norwegian-biosystematics/. Full text in Research Archive
  • Grosse, Maël Ariel & Struck, Torsten H (2022). Norwegian Cirratulid polychaetes in Norwegian waters: A museum based approach to species diversity and distribution. Full text in Research Archive
  • Masaki, Hosea & Rämä, Teppo (2026). Biodiversity and interaction studies on marine microbes: Insights from culturing and DNA metabarcoding to reveal the hidden diversity and bioactive potential of marine fungi and actinobacteria. UiT Norges arktiske universitet. ISSN 9788282663076. Full text in Research Archive

View all works in NVA

Published Mar. 2, 2023 3:04 PM - Last modified Feb. 20, 2026 11:32 PM