About the finding of Lepidochitona cinerea (Linnaeus, 1767) in the Tsemes Bay (the Black Sea)

Abstract

Chitons inhabiting natural hard substrates in the Tsemes Bay pseudolittoral from the central beach of Novorossiysk to the Cape Khako were investigated in summer and winter periods of 2022–2023. For the first time in the Tsemes Bay, a local population of Lepidochitona cinerea (Linnaeus, 1767) (Polyplacophora, Tonicellidae) was recorded on substrates of sedimentary origin. It is a rare species, and over the past 70 years, it was found in waters of the North Caucasus only three times. We registered 34 L. cinerea specimens with a maximum shell length of 8 mm. The age of the largest individuals (three years) was determined by the annual rings of the apex of the first shell shield. The species is distributed in the upper horizon of the Cape of Love pseudolittoral and is confined to supralittoral baths. A similar biotope, where the chiton was found as well, was discovered in 50 km from the Tsemes Bay. As assumed, the occurrence of the mollusc in the water area is precisely due to the presence of this bionomic type of habitat – supralittoral baths which are not expressed in other study sites of the bay. The aim of the research is to describe L. cinerea populations in a previously unspecified biotope for this species and to identify the features of this biotope and its possible effect on the chiton occurrence. Information on the geographic distribution and biotopic confinement of the species was updated. The effect of ecological, hydrochemical, and geomorphological features of the biotope on L. cinerea occurrence was considered.

Keywords

• Lepidochitona cinerea
• pseudolittoral
• supralittoral baths
• Tsemes Bay
• Black Sea