#Snails are primarily marine #mollusks. According to current hypotheses, the #sistergroup might be #Cephalopoda plus #Scaphopoda (Link below) . One #Apomorphy, i.e. evolutionary new acquisitions of the stemspecies, is the #asymmetrical #shell that is wound in one direction, which is due to a #torsion of the #mantle and visceral sac.
The species in my #photos is #Cornu #aspersum from Italy. #biodiversity,
© #StefanFWirth Berlin 2025

Reference

Sumner-Rooney et al. (2015):
https://doi.org/10.1111%2Fede.12164

Sister group (Evolutionary biology 🧬)

In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative of another given unit in an evolutionary tree.

https://en.wikipedia.org/wiki/Sister_group

#SisterGroup #Taxa #Phylogenetics #EvolutionaryBiology #BiologicalClassification