#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

Un troisième #dentale de #Méditerranée a désormais sa fiche sur le site DORIS :
Le dentale à côtes inégales.

MÜLLER Yves, LE GRANCHÉ Philippe in : #DORIS, 28/02/2024 :
Antalis inaequicostata (Dautzenberg, 1891), https://doris.ffessm.fr/ref/specie/5657

#biodiversite #Mollusques #Scaphopoda #biodiversity #DéfenseDEléphant #Dentaliidae #biodiversità

#Genomes of enigmatic tusk shells provide new insights into early molluscan #evolution https://phys.org/news/2023-09-genomes-enigmatic-tusk-shells-insights.html

#Scaphopoda is the sister taxon to #Bivalvia: Evidence of ancient incomplete lineage sorting https://www.pnas.org/doi/10.1073/pnas.2302361120

"#Scaphopods exhibit a mosaic of features resembling other lineages: tentacles like the arms of #cephalopods, unique shell ontology similar to #bivalves, and a partially degenerated head that seemingly represents an intermediate state between bivalves and #gastropods"