On growth and form of a heteromorphic terrestrial snail: Plectostoma concinnum (Fulton, 1901) (Mollusca: Gastropoda: Diplommatinidae)

Naturalis Biodiversity Center, Leiden, The Netherlands.
Institute Biology Leiden, Leiden Univerisity, Leiden, The Netherlands
Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
Centrum Wiskunde & Informatica, Amsterdam, The Netherlands
Anatomy Department, University of California San Francisco, San Francisco, California, United States
DOI
10.7287/peerj.preprints.289v1
Subject Areas
Developmental Biology, Evolutionary Studies, Zoology
Keywords
3D morphometrics, Malaysia, Limestone hills, open coiling, Borneo, Opisthostoma, commarginal ribs, radial ribs
Copyright
© 2014 Liew et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ PrePrints) and either DOI or URL of the article must be cited.
Cite this article
Liew T, Kok AC, Schilthuizen M, Urdy S. 2014. On growth and form of a heteromorphic terrestrial snail: Plectostoma concinnum (Fulton, 1901) (Mollusca: Gastropoda: Diplommatinidae) PeerJ PrePrints 2:e289v1

Abstract

The molluscan shell can be viewed as a petrified representation of the organism’s ontogeny and thus can be used as a record of changes in form during growth. However, little empirical data is available on the actual growth and form of shells, as these are hard to quantify and examine simultaneously. To address these issues, we studied the growth and form of a heteromorphic and heavily ornamented land snail – Plectostoma concinnum. The growth data were collected in a natural growth experiment and the actual form changes of the aperture during shell ontogeny were quantified. We used an ontogeny axis that allows data of growth and form to be analysed simultaneously. Then, we examined the association between the growth and the form during three different whorl growing phases, namely, the regular coiled spire phase, the transitional constriction phase, and the distortedly-coiled tuba phase. In addition, we also explored the association between growth rate and the switching between whorl growing mode and rib growing mode. As a result, we show how the changes in the aperture ontogeny profiles in terms of aperture shape, size and growth trajectory, and the changes in growth rates, are associated with the different shell forms at different parts of the shell ontogeny. These associations suggest plausible constraints that underlie the three different shell ontogeny phases and the two different growth modes. We found that the mechanism behind the heteromorphy is the rotational changes of the animal’s body and mantle edge with respect to the previously secreted shell. Overall, we propose that future study should focus on the role of the mantle and the columellar muscular system in the determination of shell form.