Molluscan evo-devo

Nontorsion Marisa

A long-lasting debate is held about the how and why of gastropod torsion. The term describes a phylogenetic and ontogenetic 180° rotation of the visceral sac and contained organs relative to head and foot region. Effects of this rotation are said to be a gut bent to open up anteriorly, gills (ctenidia) that lie in an anterior mantle cavity and nerve cords between the pleural and visceral ganglia that are arranged in a crossing, figure-of-eight-like form, while one connection traverses above and one below the intestinal tract. This is called streptoneury. By arresting torsion during ontogeny we are able to analyse the formation, arrangement and position of organs such as gut, mantle, shell and the nervous system. A particular focus is on the role of torsion for streptoneury, challenging century-old ideas about relationships.

Turning snails into slugs

Snail-slug conversion: Morphological variation in organisms including epigenetically induced body plan modifications in gastropods.

detailed project description

Key publications:

Link A, Triebskorn R, Köhler H-R (2019): TGF-β signalling is involved in torsion and shell positioning in the giant ramshorn snail Marisa cornuarietis (Gastropoda: Ampullariidae). Journal of Molluscan Studies 85 (1): 1–10
Online available at: https://doi.org/10.1093/mollus/eyy054
Marschner L, Staniek J, Schuster S, Triebskorn R, Köhler H-R (2013): External and internal shell formation in the ramshorn snail Marisa cornuarietis are extremes in a continuum of gradual variation in development. BMC Developmental Biology 13:22.
Online available at: http://dx.doi.org/10.1186/1471-213X-13-22
Marschner L, Triebskorn R, Köhler H-R (2012): Arresting mantle formation and redirecting embryonic shell gland tissue by platinum²⁺ leads to body plan modifications in Marisa cornuarietis (Gastropoda, Ampullariidae). Journal of Morphology 273: 830-841.
Online available at: http://dx.doi.org/10.1002/jmor.20019
Marschner, L, Osterauer O, Triebskorn R, Köhler H-R (2012): Durch Platin²⁺ ausgelöste Schaleninternalisierung bei der Paradiesschnecke Marisa cornuarietis - Stand der Forschung. Mitt dtsch malakozool Ges 87: 11-16
Osterauer R, Faßbender C, Braunbeck T, Köhler H-R (2011): Genotoxicity of platinum in embryos of zebrafish (Danio rerio) and ramshorn snail (Marisa cornuarietis). Sci. Tot. Environ. 409(11): 2114-2119.
Online available at: http://dx.doi.org/10.1016/j.scitotenv.2011.01.060
Osterauer R, Köhler H-R, Triebskorn R (2010): Histopathological alterations and induction of stress proteins in ramshorn snail (Marisa cornuarietis) and zebrafish (Danio rerio) after exposure to PtCl₂ during embryogenesis. Aquat. Toxicol. 99(1): 100-107.
Online available at: http://dx.doi.org/10.1016/j.aquatox.2010.04.001
Osterauer R, Marschner L, Betz O, Gerberding M, Sawasdee B, Cloetens P, Haus N, Sures B, Triebskorn R, Köhler H-R (2010): Turning snails into slugs: Induced body plan changes and formation of an internal shell. Evol. Dev. 12(5): 474-483.
Online available at: http://dx.doi.org/10.1111/j.1525-142X.2010.00433.x