BIOLOGIYA MORYA, 2015, Vol. 41, No. 4, pp. 248-255

General morphology and ultrastructure of the cardiac complex of the chiton Stenosemus albus (Linnaeus, 1767) (Mollusca: Polyplacophora)

© 2015 D. A. Ozerov¹, E. V. Vortsepneva², A. B. Tzetlin³

¹A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071;
²White Sea Biological Station, M.V. Lomonosov Moscow State University, Moscow 119899;
³Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119899

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The topology of the heart and the pericardium of the chiton Stenosemus albus (Linnaeus, 1767) (Mollusca: Polyplacophora) were described as a result of the study of the general morphology and ultrastructure of the cardiac complex. Application of the method of the 3D reconstruction technology to a series of histological sections has detected three invaginations of the pericardium of S. albus. The dorsal invagination forms the ventricle, while two lateral invaginations form atrium walls. The atrial cavities are surrounded by the basement membrane of the pericardium from the inner side and by connective tissue from the outside. The investigation of the ultrastructure of cardiac complex has shown that the zones of ultrafiltration in S. albus are located both in the pericardium, as also in all other chitons described earlier, and in the ventricle, as we describe here for the first time.

Key words: Mollusca, Polyplacophora, Stenosemus albus, heart, pericardium, ultrastructure, 3D reconstruction.