Article

The use of shell features in age determination of juvenile and adult Roman snails Helix pomatia

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Abstract

Features of the shell which can be used for aging Roman snails Helix pomatia L. are described. Field evidence suggests that growth breaks in the shell correspond to resting periods during the winter in the juvenile phase of shell growth. The microstructure of the shell is described and the structure of the juvenile breaks and layering in the lip of the adult snail are shown to be similar. It is concluded that the two are analogous, that the layers at the lip are annual, and that it is theoretically possible to trace the adult shell back to the year of hatching. In practice, errors may be made in recording, but the method can be of great value in population studies.

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... A mollusk's shell potentially provides a record of environmental information in the form of bivalve shell growth bands, for example, which offer a precise chronological record as they change in response to environmental and physiological factors such as temperature (Nishida et al. 2012;Kubota et al. 2017), salinity (Schöne et al. 2013Shirai et al. 2014), and spawning (Nishida et al. 2012). Pollard et al. (1977) reported that the land snail Helix pomatia presents an annual growth break in its shell, corresponding to the winter season. Although L. pulchella has been known to spawn in temperatures of < 20 °C from September to November , the surface of the shell of L. pulchella is usually smooth, and no seasonal nor annual growth break has been observed on L. pulchella shells. ...
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Aus: Zeitschrift f. wissensch. Zool. Bd 113. Marburg, Phil. Diss. v. 4. Aug. 1915, Ref. Korschelt.
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