At the base of the siphon is the bipectinate (branching from a central axis) osphradium, a sensory receptacle and olfactory organ, that is more developed than the one in the Mesogastropoda.

They achieved important morphological changes including e.g., the elongation of the siphonal canal, a shift in the mouth opening to a terminal position on the head, and the formation of a well-developed proboscis.

[3] The monophyly of the group is widely accepted among morphologists, and it is based on several synapomorphies mostly related with the anatomy of the digestive system.

[3] Current classifications of Neogastropoda generally recognize up to six superfamilies: Buccinoidea, Muricoidea, Olivoidea, Pseudolivoidea, Conoidea, and Cancellarioidea.

Phylogenetic relationships among neogastropod superfamilies based on morphological characters are rather unstable, and for instance, Cancellarioidea[7] or Buccinoidea[8] have been alternatively proposed as the sister group of the remaining Neogastropoda.