A new species of the genus Cottus (Scorpaeniformes, Cottidae) from the Baltic Sea Basin and its phylogenetic placement
Abstract
The genus Cottus contains more than 60 species that are common in freshwater bodies of northern Eurasia and North America. Despite the abundance of species, this genus has been insufficiently studied in Eastern European rivers and lakes. The new taxon Cottus cyclophthalmus sp. nov. was found in the Neman/Nemunas and Venta river systems (Baltic Sea Basin). Cottus cyclophthalmus is sister and most morphologically similar to Cottus gobio. The new species has the following diagnostic characters: round, protruding (tubular) eyes near front of head; dermal papillae on top and sides of head, naked body, absence of bony prickles, full trunk canal with 32–36 pores. The description of Cottus cyclophthalmus and a new finding of Cottus microstomus improved understanding of the Eastern European biodiversity.
References
Alekseev N.I. & Probatov A.N. 1969. Zoogeographic essay of freshwater ichthyofauna of Kaliningrad region area. Proceedings Kaliningrad Technical Institute of Fishing Industry and Economy 24: 7–16. [In Russian.]
Berg L.S. 1949. Freshwater Fishes of Soviet Union and Adjacent Countries. Part 3. Academy of Sciences of USSR, Moscow. [In Russian.]
Bravničar J., Palandačić A., Jelić D., Podgornik S. & Snoj A. 2021. Molecular data reveal distinct phylogenetic position of Cottus metae, establish its distribution range, and invalidate the species status of C. scaturigo. Journal of Zoological Systematics and Evolutionary Research 59 (2): 428–441. https://doi.org/10.1111/jzs.12434
Freyhof J., Kottelat M. & Nolte A. 2005. Taxonomic diversity of European Cottus with description of eight new species (Teleostei: Cottidae). Ichthyological Exploration of Freshwaters 16 (2): 107–172.
Goto A., Yokoyama R. & Sideleva V.G. 2015. Evolutionary diversification in freshwater sculpins (Cottoidea): a review of two major adaptive radiations. Environmental Biology of Fishes 98 (1): 307–335. https://doi.org/10.1007/s10641-014-0262-7
Huelsenbeck J.P. & Ronquist F. 2001. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17 (8): 754–755. https://doi.org/10.1093/bioinformatics/17.8.754
Kocher T.D., Thomas W.K., Meyer A., Edwards S.V., Pääbo S., Villablanca F.X. & Wilson A.C. 1989. Dynamics of mitochondrial DNA evolution in animals: amplification and sequencing with conserved primers. Proceedings of the National Academy of Sciences 86 (16): 6196–6200. https://doi.org/10.1073/pnas.86.16.6196
Kontula T. & Väinölä R. 2001. Postglacial colonization of Northern Europe by distinct phylogeographic lineages of the bullhead, Cottus gobio. Molecular Ecology 10 (8): 1983–2002. https://doi.org/10.1046/j.1365-294X.2001.01328.x
Kumar S., Stecher G., Li M., Knyaz C. & Tamura K. 2018. MEGA X: molecular evolutionary genetics analysis across computing platforms. Molecular Biology and Evolution 35 (6): 1547–1549. https://doi.org/10.1093/molbev/msy096
Nguyen L.T., Schmidt H.A., Von Haeseler A. & Minh B.Q. 2015. IQ-TREE: a fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Molecular Biology and Evolution 32 (1): 268–274. https://doi.org/10.1093/molbev/msu300
Rozas J., Ferrer-Mata A., Sánchez-DelBarrio J.C., Guirao-Rico S., Librado P., Ramos-Onsins S.E. & Sánchez-Gracia A. 2017. DnaSP 6: DNA sequence polymorphism analysis of large data sets. Molecular Biology and Evolution 34 (12): 3299–3302. https://doi.org/10.1093/molbev/msx248
Sideleva V.G. 1982. Seismosensory System and Ecology of Baikal Sculpin (Cottoidei). Nauka, Novosibirsk. [In Russian.]
Sideleva V.G. 2009. A new species of sculpin Cottus sabaudicus sp. nova (Scorpaeniformes: Cottidae) from the Savoy region, France. Journal of Ichthyology 49 (3): 209–214.
Sideleva V.G., Prirodina V.P., Reshetnikov Y.S. & Zhidkov Z.V. 2015a. Redescription of Cottus koshewnikowi (Cottidae) and its morphological variability in tributaries of the Upper Volga. Journal of Ichthyology 55 (1): 30–39. https://doi.org/10.1134/S0032945215010191
Sideleva V.G., Naseka A.M. & Zhidkov Z.V. 2015b. A new species of Cottus from the Onega River drainage, White Sea basin (Actinopterygii: Scorpaeniformes: Cottidae). Zootaxa 3949 (3): 419–430. https://doi.org/10.11646/zootaxa.3949.3
Sideleva V.G., Naseka A.M., Nowak M. & Palandačić A. 2019. The finding of holotype and redescription of Cottus microstomus Heckel 1837 (Cottidae). Ichthyological Research 66: 249–257. https://doi.org/10.1007/s10228-018-00676-4
Šlechtová V., Bohlen J., Freyhof J., Persat H. & Delmastro G.B. 2004. The Alps as barrier to dispersal in cold-adapted freshwater fishes? Phylogeographic history and taxonomic status of the bullhead in the Adriatic freshwater drainage. Molecular Phylogenetics and Evolution 33 (1): 225–239. https://doi.org/10.1016/j.ympev.2004.05.005
Somers K.M. 1986. Multivariate allometry and removal of size with principal components analysis. Systematic Biology 35 (3): 359–368.
Taliev D.N. 1955. Sculpins of Lake Baikal (Cottoidei). Academy of Sciences of USSR, Moscow. [In Russian.]
Tylik K.V. & Shibaev S.V. 2008 (eds) Lake Vyshtynetskoe. Kaliningrad State Technical University, Kaliningrad. [In Russian.]
Witkowski A. 1979. A taxonomic study on freshwater sculpins of genus Cottus Linnaeus, 1758 (Cottus gobio L. and Cottus poecilopus Heck.) in Poland. Acta Universitatis Wratislaviensis 458: 1–95.
Yabe M. 1985. Comparative osteology and myology of the superfamily Cottoidea (Pisces: Scorpaeniformes), and its phylogenetic classification. Memoirs of the Faculty of Fisheries, Hokkaido University 32 (1): 1–130.
Yokoyama R. & Goto A. 2005. Evolutionary history of freshwater sculpins, genus Cottus (Teleostei; Cottidae) and related taxa, as inferred from mitochondrial DNA phylogeny. Molecular Phylogenetics and Evolution 36 (3): 654–668. https://doi.org/10.1016/j.ympev.2005.06.004
Yokoyama R., Sideleva V.G., Shedko S.V. & Goto A. 2008. Broad-scale phylogeography of the palearctic freshwater fish Cottus poecilopus complex (Pisces: Cottidae). Molecular Phylogenetics and Evolution 48: 1244–1251. https://doi.org/10.1016/j.ympev.2008.02.002
Zhang J., Kapli P., Pavlidis P. & Stamatakis A. 2013. A general species delimitation method with applications to phylogenetic placements. Bioinformatics 29 (22): 2869–2876. https://doi.org/10.1093/bioinformatics/btt499
Zhukov P.I. 1958. Fishes of the Neman River basin (within Belorussian SSR). Belgosizdat, Minsk. [In Russian.]
Zograf Y.N. 1907. Preliminary Report on the Trip with Ichthyological Purpose to Sventsyanskiy, Vilenskiy and Trokskiy Districts of Vil’na Province and Grodno District of Grodno Province in 1904. Proceedings of Department of Ichthyology of Imperial Russian Society for Acclimatization of Animals and Plants 5, Moscow. [In Russian.]
Copyright (c) 2022 Valentina Sideleva, Vytautas Kesminas, Zakhar Zhidkov

This work is licensed under a Creative Commons Attribution 4.0 International License.
Creative Commons Copyright Notices
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License (CC BY 4.0) that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are NOT ALLOWED TO post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to taxonomic issues.