Dreissena caspia Eichwald, 1855 (Fig. 8: 1–3). *1855 Dreissena caspia Eichwald: 311 –312, pl. 10, figs. 19–21. 2013 Dreissena caspia Eichwald, 1855 – Bogutskaya et al.: 321, fig. 109. Dimensions – max. L 7.4 mm, H 22.7 mm. Characterization – Elongate, somewhat flat Dreissena with rounded margins; keel low or absent resulting in rounded crossprofile. The semidiameter is initially located at the dorsal margin but in sub adult stages crosses to the ventral margin. In adult stages, the semidiameter becomes less pronounced and is located in the middle of the shell. The posterodorsal margin is broadly rounded (and not subangular as in D. elata), the posterior margin is rounded and the anterior margin is straight to slightly round. The hinge platform is flat and solid. Ecology – Dreissena caspia is a filter feeder that used to be common all over the CS but is now possibly extinct (Bogutskaya et al., 2013). The species seems to be completely outcompeted by Mytilaster minimus (Logvinenko and Starobogatov, 1969). The species was most abundant at depths up to 40 m (Logvinenko and Starobogatov, 1969), and in a salinity range between 2 and 8 psu (Bogutskaya et al., 2013).

Published as part of van de Velde, Sabrina, Yanina, Tamara A., Neubauer, Thomas A. & Wesselingh, Frank P., 2020, The Late Pleistocene mollusk fauna of Selitrennoye (Astrakhan province, Russia): A natural baseline for endemic Caspian Sea faunas, pp. 1227-1239 in Journal of Great Lakes Research 46 (5) on page 1236, DOI: 10.1016/j.jglr.2019.04.001, http://zenodo.org/record/5019200