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Evolution of marine invertebrates – New species of shell-boring worms in Norway (Natural History Museum)

Introduction

Considering animals most people think about vertebrates and thereby especially mammals and birds. These are often considered the most sophisticated and evolutionary successful animals on Earth. However, this is not true taking into account evolutionary history, biodiversity, ecology or biomass. Invertebrates outshine vertebrates in all these categories. Moreover, invertebrates have evolved novel structures and inhabited habitats unoccupied by vertebrates. Hence, invertebrates have much to teach us about evolution in general and in particular. On the other hand, except for a few flagship species and groups, invertebrates are heavily understudied, especially considering marine invertebrates. The latter is especially important as all animals live depends on water and originated from the marine realm. Hence, understanding the evolution of marine invertebrates will help us to understand evolution at much more detailed and complete level.

The topic of this thesis will build upon the results of the ArtsDatabanken-project “Biodiversity in the marine algae belt”. The marine algae belt comprising kelp forests, seagrass meadows and rocky reefs with coralline red seaweeds is one of the most active primary producing environments in the sea. It also harbors a great diversity of animals including sea squirts, ribbon worms, nick worms, serpulid worms, spionid worms and skeleton shrimps. The species of these groups occupy important ecological functions as herbivores, predators and filter feeding organisms and can be sessile or agile as well as solitary or colonial. Globally these taxa comprise more than 7,000 species with around 250 species documented from Norwegian waters. This is why we conducted a field inventory and collected species of these taxa in Norway (from the Skagerrak up to Troms?). With morphological and molecular methods, we determined species and learned more about their distribution and their association with Norwegian nature types. These efforts resulted into the record of 624 collection samples with 944 specimens of 73 species from these animal groups and 43 localities in Viken, Tr?ndelag, Vestland, and Troms og Finnmark comprising 19 Norwegian nature types. Our results show that we have found 3 species and 1 subspecies, which are new to Norway, and at least 10, which are new to science, but there may be 7 additional ones. However, the first analyses concerning the new species also showed that much more detailed studies on these are necessary. This is where this Master project will work on.

Annelida (segmented worms) is a species-rich group with >20,000 species occurring in all habitats on Earth. In the three targeted habitats many different annelid families are found ranging from filter-feeding species to predators and these occupy different positions in the food webs of these habitats. Herein, we concentrated on the family Spionidae occurring in these habitats (e.g., the spionid Polydora). Spionidae are agile organisms, which are also suspension feeders. Some spionid species are known as very successful invasive species, which might cause substantial economic losses due to burrowing in bivalve shells in aquaculture.

We found only relatively few specimens and most of them are shell-boring species. Hence, they are not directly associated with algae and sea grass habitats, but with mollusk shell occurring there. Nonetheless, we found 11 species with about 80 specimens. Of these, two species are new to science and are morphologically similar to the genus Dipolydora. Both are genetically clearly different from Dipolydora giardi in our analyses. On the other hand, for one of them the closest match in GenBank is to Polydora aura with a genetic difference of 17.5%. However, in the preliminary molecular tree, it is sister Dipolydora giardi and not Polydora onagawaensis. It is associated with kelp and occurs at one locality in the Trondheim region. The other new Dipolydora species has the closest match with a difference of 20% to Polydora and Dipolydora species in NCBI. In tree, it is sister to Pygospio elegans and not Dipolydora giardi and Polydora onagawaensis. It occurs at seagrass meadows of one locality in the Trondheim region. Finally, another new Malacoceros species, which is morphologically different from other known Malacoceros species of Norway, has been found in associated with kelp habitats from two localities in the Trondheim region. It is about 19% genetically different to other spionid species including Malacoceros in BOLD and in NCBI. These three species require detailed taxonomic revisions including a broader taxon sampling of different spionid species of both molecular and morphological data and including specimens from beyond Norway. In your thesis, you obtain additional molecular data for new markers and specimens, as well as conduct detailed morphological studies using different forms of microscopy. You will compare your data with the publicly available data and literature and conduct a taxonomic revision of the species in Norwegian waters.

Bildet kan inneholde: plante, rektangel, kunst, font, tre.

What you will learn:

You will learn to conduct taxonomic identification, extensive literature research and distribution mapping. This will include among others molecular barcoding and microscopy. You will apply programs for phylogenetic reconstruction and conduct statistical analyses of your results.

What we offer:

First and foremost, we offer a friendly and kind mentoring environment. We offer a membership in ForBio (the research school in biosystematics) where you will be able to take courses in several places in Norway. You will potentially be able to attend international courses if they fit with the objectives. You will be able to participate in a national conference (ForBio meeting) and potentially in an international conference depending on funding. If you are interested, we will be able to discuss travel opportunities and a travelling period abroad. 

What we expect from you:

Commitment and dedication

Outcomes:

One (or more) scientific publications, conference communication

Supervision and teaching:

You will be supervised by Torsten Struck, Ana Teresa Capucho (both UiO), and Vasily Radashevsky (University of Vladivostok).

 

For further inquiries, please contact Torsten Struck (t.h.struck@nhm.uio.no)

Publisert 19. aug. 2024 12:01 - Sist endret 19. aug. 2024 16:57

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