invasiveness; shell formation; morphometric ratios; index of roundness;
pp. 167 -

Molluscs of the genus Corbicula, first discovered in the lower Don River (Novocherkasskaya TPP warm channel area) in 2017, were identified as Corbicula fluminea based on their conchological features.  The aim of the present work was to obtain new data on morphometry and peculiarities of shell-shape forming of molluscs of this species from the Don River in ontogenesis. Using the main morphometric parameters of the shell – length (L), width (D) and height (H) – changes in its frontal (D/L), sagittal (H/L) curvature (=Index of Roundness), convexity ((H+D)/L) and conditional volume (H×D×L/1000) indices during ontogeny were shown. The relevant equations of dependencies are given. The conclusion was made about the interval type of changes in the indicated curvature indices, which determine the corresponding changes in the relative volume of the shells in ontogenesis.. Their graphs have a dome-shaped character with reaching values in the range of shell lengths 15–25 mm, reliably exceeding similar values in the intervals up to 15 and more than 25 mm. Sexual maturation and the onset of reproduction of molluscs occurs at the stage of increasing relative shell volume. This strategy of shell formation, aimed at creating the maximum internal relative volume of the shell during the period of gonad formation, especially in the androgenic C. fluminea, which incubates larvae, may be one of the characteristics that determine the reproductive capacity of the species and, consequently, its invasiveness.

Особенности аллометрического роста двустворчатого моллюска-вселенца Corbicula fluminea (Bivalvia: Cyrenidae) из бассейна реки Дон
Живоглядова Л.А.; Ревков Н.К.; Гуськова О.С.; Шкоркин Р.А; Хренкин Д.В.;