Boreomysinae is a primitive group, uniquely distinguished from other subfamilies of Mysidae by the presence of the seven pairs of oostegites,[3] which can be maximum four in other subfamilies, and by the incomplete proximal suture on the uropodal exopods (either complete and distal or completely absent in the rest of subfamilies).[2]
Boreomysinaes show wide diversity in the structure of eyes, from rather reduced to large with well-developed cornea.[4]
Abdominal pleomeres lacking pleural plates.[7]Telson not armed in anterior part, but having apical cleft,[8] lacking plumose setae.[7] Appendix masculina present as slight tubercle with a bunch of setae.[8]Labrum not armed apically;[8] thought its right lobe with inward-bent process. Antennal scale with smooth outer margin, terminating with non-articulated spine.[7][9]Pereopod endopods not differentiated; only pereopod 1 slightly stronger than others; carpus and propodus divided by oblique articulation;[3] internal articulation of the propodus transverse. Marsupium (brood pouch) made of seven plates (oostegites),[10] present
on maxillipeds 2 and all six pereopods of females. Penes tubular. Pleopods reduced to unsegmented plates in females. In males pleopods always well-developed,[11] biramous; endopod 1 non-segmented; other endopods and all five exopods multisegmented; endopods with movable preudobranchial lobe; exopod 3, and sometimes
also exopod 2 modified, with stronger and shorter setae on terminal segments.[8]Uropodal exopod with incomplete proximal suture, its segment 1 bearing distolateral spiniform setae;[10] endopod entire, without signs of articulation. Balance organ (statolith) in the endopod of organic composition,[12] somewhat reduced[13][14]
Boremysine individuals are the largest mysids: body length of some species reaches up to 85 cm.[2]
Boreomysines were originally thought to be close to Leptomysinae, another subfamily with well-developed biramous pleopods.[10] According to molecular genetic studies, Boreomysinae form a monophyletic clade, basal to most of Mysidae, and somewhat close to Rhopalophthalminae, also with articulated uropodal exopod and organic statolith.[15] A detailed comparison suggests them to be structurally more similar to Siriellinae, sharing uropodal exopod articulation, its armature, non-differentiation of pereopods, non-reduction of pleopods and their apical modification.[2]
Their basal position, corresponds to their primitive structure. Estimates of the molecular clock make boremysines some 242,7 million years old.[6]
Boreomysine mysids are mostly deep-water oceanic crustaceans. Certain species, however, have been described from relatively shallow epi- and mesopelagic waters (members of the subgenus Boreomysis (Petryashovia). Some deep-water species also occasionally penetrate epipelagic zone. Some species have also been found in inland seas, like Marmora Sea, thus deviating from purely oceanic habits.[2]
^ abHansen, H J. (1925). Studies on Arthropoda. II. Copenhagen, Gyldendalske Boghandel.
^Holt, E.W.L.; Tattersall, W.M. (1906). "Schizopodous Crustacea from the north-east Atlantic slope". Supplement. Fisheries, Ireland, Scientific Investigations, 1904. V: 1–50.
^Petryashov, V.V. (1993). "Deep-sea mysids (Crustacea, Mysidacea) of the Arctic Basin (Arctic Ocean)". Morskoi Plankton. Sistematica, Ekologiya I Rasprostranenie, II. Issledovaniya Fauny Morei. 45 (53): 70–89 [in Russian, with English abstract.]
^ abKou, Q.; Meland, K.; Li, X.; He, L.; Wang, Y. (2020). ""Unicorn from Hades", a new genus of Mysidae (Malacostraca: Mysida) from the Mariana Trench, with a systematic analysis of the deep-sea mysids". Molecular Phylogenetics and Evolution. 143:106666. doi:10.1016/j.ympev.2019.106666. PMID31669817. S2CID204969925.
^ abcKathman, R.D.; Austin, W.C.; Saltman, J.C.; Fulton, J.D. (1986). "Identification Manual to the Mysidacea and Euphausiacea of the Northeast Pacific". Canadian Special Publication of Fisheries and Aquatic Sciences. 93: 1–411.
^Wittmann, K. J., A. P. Ariani, and J.-P. Lagardère. (2014) Orders
Lophogastrida Boas, 1883, Stygiomysida Tchindonova, 1981,
and Mysida Boas, 1883 (also known collectively as Mysidacea),
pp. 189–396, 404–406. In Treatise on Zoology—Anatomy, Taxonomy, Biology. The Crustacea. Revised and updated, as well as extended from the Traité de Zoologie, ed. J. C. von Vaupel Klein, M. Charmantier-Daures, and F. R. Schram, Vol.
4 Part B (54)
^ abcdHolt, E. W. L.; Tattersall, W.M. (1905). "Schizopodous Crustacea from the north-east Atlantic slope". Reports on the Sea and Inland Fisheries of Ireland, 1902–1903. 2 (4): 99–152.
^Zimmer, C. 1909. Die nordischen Schizopoden (inkl. Nachtrag zu Mysis oculata (Fabr.). In Nordisches Plankton, ed. K. Brandt and
C. Apstein. Kiel and Leipzig: Lipsius und Tischer, 12: 1–179
^Banner, A. H. (1948). "A taxonomic study of the Mysidacea and Euphausiacea (Crustacea) of the northeastern Pacific, Part II. Mysidacea, from tribe Mysini through subfamily Mysidellinae". Transactions of the Royal Canadian Institute. 27: 65−124.
^ abMeland, K.; Willassen, E. (2007). "The disunity of "Mysidacea" (Crustacea)". Molecular Phylogenetics and Evolution. 44 (3): 1083–1104. doi:10.1016/j.ympev.2007.02.009. PMID17398121.
^Holmquist, C. (1957). "Mysidacea of Chile. Reports of the Lund University Chile Expedition 1948–49. (Report 28)". Lunds Universitets Årsskrift 2. 53 (6): 1–52.
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