Embryonic staging of the brown garden snail, <i>Cornu aspersum</i> (Gastropoda: Stylommatophora), an emerging model gastropod

ABSTRACT Comparative developmental research within Gastropoda has flourished in recent decades with modern advancements in imaging techniques and experimental manipulations. Data from marine and aquatic gastropod models have proven vital to understanding morphogenetic processes such as spiral cleavage and the establishment of chirality. However, there remains a paucity of knowledge on terrestrial pulmonate gastropod embryonic development, which impedes investigating major evolutionary transitions within Gastropoda, with emphasis on terrestrialization. The brown garden snail Cornu aspersum (Stylommatophora: Helicidae) is an economically, medically and environmentally important pulmonate gastropod with a widespread distribution. Here, we provide a description of the complete embryonic development of C. aspersum and an embryonic staging system in tandem with protocols for in ovo culture, immunohistochemistry and fluorescent in situ hybridization.