Marianne Nilsen Haugen

• Haugen, Marianne N.; Gusarov, Vladimir; Sikes, Derek S. & Struck, Torsten H. (2025). Insight Into the Phylogeny of the Intertidal Beetle Genus Aegialites (Coleoptera, Salpingidae). Zoologica Scripta. ISSN 0300-3256. doi: 10.1111/zsc.70035. Full text in Research Archive Show summary

  Aegialites Mannerheim, 1853 (Coleoptera: Salpingidae) is an understudied genus. These beetles inhabit rock crevices in the supralittoral to intertidal zones. They have widely separated coxae, large claws and are flightless. Despite their limited vagility they are broadly distributed along the northern Pacific coast, from California to northern Japan. Phylogenetic relationships and species richness within Aegialites remain unclear, with historical morphological assessments yielding 4–30 species. Recent molecular studies have suggested potential cryptic species may exist. We present the first molecular phylogenetic analysis of Aegialites based on one mitochondrial gene (cytochrome oxidase I) and one nuclear gene (ribosomal internal transcribed spacer 2) from over 160 specimens across 96 localities, as well as the complete mitochondrial genome and the 18S nuclear gene for several specimens. Our phylogenetic analyses revealed three major clades, one corresponding to Alaska, Canada and Northern California; a sister clade from Russia and Japan; and a separate clade for southern California. Haplotype networks, along with calculations of FST and P‐distance, supported our findings. Based on these analyses, we have evidence for seven species of Aegialites . However, fixing the taxonomy of Aegialites will require integration of morphology and further molecular analyses.

• Haugen, Marianne Nilsen; Gusarov, Vladimir & Struck, Torsten H (2024). The complete mitochondrial genome of Aegialites californicus (Motchoulsky, 1845) (insecta: coleoptera: salpingidae). Mitochondrial DNA Part B: Resources. 9(1), p. 214–218. doi: 10.1080/23802359.2024.2309255. Full text in Research Archive Show summary

  The flightless intertidal beetle genus Aegialites (family Salpingidae) is distributed along the Northern Pacific coasts, from California to Alaska and from Northern Japan to Kamchatka. Systematics of Aegialites and its phylogenetic relationships to other members of Salpingidae are unclear, and little genetic information is available. We here present the first complete mitochondrial genome of this genus, represented by Aegialites californicus (Motchoulsky, 1845) from Sonoma County, California, U.S.A. The complete mitochondrial genome of A. californicus is 15,899 bp long and comprises 13 protein-coding (PCG), two ribosomal RNA (rRNA) and 22 transfer RNA (tRNA) genes. The phylogenetic analysis places A.californicus as sister to other members of family Salpingidae. The mitochondrial genome sequence of A. californicus will contribute to future phylogenetic and taxonomic studies of genus Aegialites, family Salpingidae and superfamily Tenebrionoidea.

• Orr, Russell; Haugen, Marianne Nilsen; Berning, Björn; Bock, Phil; Cumming, Robyn L. & Florence, Wayne [Show all 14 contributors for this article] (2019). A genome-skimmed phylogeny of a widespread bryozoan family, Adeonidae. BMC Evolutionary Biology. 19(235). doi: 10.1186/s12862-019-1563-4. Full text in Research Archive Show summary

  Background Understanding the phylogenetic relationships among species is one of the main goals of systematic biology. Simultaneously, credible phylogenetic hypotheses are often the first requirement for unveiling the evolutionary history of traits and for modelling macroevolutionary processes. However, many non-model taxa have not yet been sequenced to an extent such that statistically well-supported molecular phylogenies can be constructed for these purposes. Here, we use a genome-skimming approach to extract sequence information for 15 mitochondrial and 2 ribosomal operon genes from the cheilostome bryozoan family, Adeonidae, Busk, 1884, whose current systematics is based purely on morphological traits. The members of the Adeonidae are, like all cheilostome bryozoans, benthic, colonial, marine organisms. Adeonids are also geographically widely-distributed, often locally common, and are sometimes important habitat-builders. Results We successfully genome-skimmed 35 adeonid colonies representing 6 genera (Adeona, Adeonellopsis, Bracebridgia, Adeonella, Laminopora and Cucullipora). We also contributed 16 new, circularised mitochondrial genomes to the eight previously published for cheilostome bryozoans. Using the aforementioned mitochondrial and ribosomal genes, we inferred the relationships among these 35 samples. Contrary to some previous suggestions, the Adeonidae is a robustly supported monophyletic clade. However, the genera Adeonella and Laminopora are in need of revision: Adeonella is polyphyletic and Laminopora paraphyletically forms a clade with some Adeonella species. Additionally, we assign a sequence clustering identity using cox1 barcoding region of 99% at the species and 83% at the genus level. Conclusions We provide sequence data, obtained via genome-skimming, that greatly increases the resolution of the phylogenetic relationships within the adeonids. We present a highly-supported topology based on 17 genes and substantially increase availability of circularised cheilostome mitochondrial genomes, and highlight how we can extend our pipeline to other bryozoans.

• Orr, Russell; Waeschenbach, Andrea; Enevoldsen, Emily; Boeve, Jeroen Pieter; Haugen, Marianne Nilsen & Voje, Kjetil L. [Show all 11 contributors for this article] (2018). Bryozoan genera Fenestrulina and Microporella no longer confamilial; multi-gene phylogeny supports separation. Zoological Journal of the Linnean Society. ISSN 0024-4082. p. 1–10. doi: 10.1093/zoolinnean/zly055. Full text in Research Archive Show summary

  Bryozoans are a moderately diverse, mostly marine phylum with a fossil record extending to the Early Ordovician. Compared to other phyla, little is known about their phylogenetic relationships at both lower and higher taxonomic levels. Hence, an effort is being made to elucidate their phylogenetic relationships. Here, we present newly sequenced nuclear and mitochondrial genes for 21 cheilostome bryozoans. Combining these data with existing orthologous molecular data, we focus on reconstructing the phylogenetic relationships of Fenestrulina and Microporella, two species-rich genera. They are currently placed in Microporellidae, defined by having a semicircular primary orifice and a proximal ascopore. Our six-gene phylogenetic analysis reveals that the genera Fenestrulina and Microporella are each monophyletic, with the sister clade to Microporella comprising non-microporellids. Our result hence supports the reinstatement of the family Fenestrulinidae Jullien, 1888 for Fenestrulina and genera with comparable frontal shield and ooecial morphologies. Our well-supported phylogeny, based on independent molecular data, lends credit to existing phylogenetic hypotheses based on morphological observations but does not conform to the current classification of these bryozoans. This illustrates the general need for a rethink of bryozoan higher level systematics, ideally based on both morphological and molecular data.

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• Haugen, Marianne Nilsen (2025). Door 6: Taxonomy – past and present – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen (2025). Door 10 – Species delimitation – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen (2025). Door 19: New paper out: Insight into the phylogeny of the intertidal beetle genus Aegialites (Coleoptera, Salpingidae). – Blogs of the CEG research group. Full text in Research Archive
• Capucho, Ana Teresa; Berggren, Matz; Haugen, Marianne Nilsen; Stach, Thomas; Valero-Gracia, Alberto & Döhren, Jörn von [Show all 8 contributors for this article] (2021). Assessing biodiversity in the marine algae belt. Full text in Research Archive Show summary

  The marine algae belt, more loosely interpreted, comprises kelp forests, seagrass meadows and rocky reefs with coralline red seaweeds. It is one of the most active primary producing environments in the sea and harbors a great diversity of animals including ascidians, nemerteans, entoprocts, serpulid worms, spionid worms and caprellids. The species of these groups occupy important ecological functions as herbivores, predators or 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. Despite this, the knowledge about their taxonomy and distribution in Norway is poor and in dire need of improvement. Specimens in museum collections are often quite old material, which additionally is often wrongly determined due to unresolved taxonomic issues including the high degree of cryptic species in these groups. Besides cryptic species, many of these taxa include invasive species causing high economic damage. This recently started project, funded by ArtsDatabanken, is focusing on the occurrence and habitat preferences of the above-mentioned taxa in the marine algae belt along the Norwegian coastline. Using both morphological and molecular methods, it aims to contribute to basic biosystematics, species distribution and nature conservation in groups that are still poorly understood and challenging to study. Fieldwork was conducted last summer in two locations: Oslofjord and Trondheim area. The Oslofjord sampling effort was carried out with the help of two students from the UiO:Life science project. First results include new records of species for both sampled locations and several high-quality barcodes (CO1 sequences) that will be uploaded to NorBOL. Revision of museum collections, species lists and popular and scientific papers will be prepared in the next months. We also hope for more exciting results following the DNA sequencing that will be carried out this autumn.

• Haugen, Marianne Nilsen; Struck, Torsten H & Bachmann, Lutz (2021). Kryptiske arter utfordrer taksonomer og evolusjonsbiologer. Naturen. ISSN 0028-0887. 2021(1), p. 19–26. doi: 10.18261/issn.1504-3118-2021-01-03. Full text in Research Archive
• Haugen, Marianne Nilsen; Gracia, Alberto Valero; Cerca, José; Fleming, James Frederick; Austin, Rita M & Gusarov, Vladimir [Show all 8 contributors for this article] (2020). International Happy Seasons – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen; Gracia, Alberto Valero; Austin, Rita M; Bachmann, Lutz & Struck, Torsten H (2020). Combining group fun with genomic research – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen; Bachmann, Lutz & Struck, Torsten H (2020). Beetles, sheep and the Faroes – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen; Bachmann, Lutz & Struck, Torsten H (2020). The intertidal beetle genus Aegialites – Blogs of the CEG research group. Full text in Research Archive
• Haugen, Marianne Nilsen; Novosel, Maja; Wisshak, Max & Berning, Björn (2020). The genus Reptadeonella (Bryozoa, Cheilostomatida) in European waters: There’s more in it than meets the eye. International Bryozoology Association (IBA) Conferences. Full text in Research Archive
• Haugen, Marianne Nilsen; Struck, Torsten H; Gusarov, Vladimir & Sikes, Derek (2026). Species diversity, geographic ranges and genetic connectivity in organisms with limited dispersal capacity. A case study of the flightless intertidal beetle genus Aegialites Mannerheim, 1853. Universitetet i Oslo. Full text in Research Archive Show summary

  Flightless organisms are generally expected to have limited dispersal, yet some occupy remarkably large geographic ranges. This thesis investigates this apparent paradox in Aegialites, a genus of small, flightless beetles specialized to rocky intertidal habitats and distributed across much of the North Pacific. By combining molecular, genomic and population genomic approaches, the thesis establishes the first comprehensive evolutionary framework for Aegialites. The results support substantially fewer species than previously proposed based on morphology, while also revealing previously unrecognized diversity. The first mitochondrial and high-quality nuclear genomes for the genus were generated. The genomes were relatively compact, and comparisons with other beetles revealed no evidence that adaptation to the intertidal environment involved extensive changes in genome organization or gene content. Population genomic analyses revealed strong geographic structure, but striking differences in connectivity among regions. California populations were strongly genetically differentiated across relatively short distances, whereas populations from Russia and Japan retained evidence of connectivity across more than 1,500 kilometers. Together, these findings show that limited active dispersal can generate strong population structure locally without preventing broad geographic distributions over evolutionary timescales. Historical demographic processes and occasional long-distance dispersal may therefore both contribute to the distribution of these flightless beetles.

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