Contents

Neritimorpha

Neritimorpha Temporal range: Early Ordovician – Recent PreꞒ Ꞓ O S D C P T J K Pg N
Examples of Neritimorpha
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Neritimorpha
Clades
See text
Synonyms
Neritopsina Cox & Knight, 1960

Neritimorpha is a clade of gastropod molluscs that contains around 2,000 extant species of sea snails, limpets, freshwater snails, land snails and slugs.^[1] This clade used to be known as the superorder Neritopsina.

Etymology[edit]

The clade’s name, Neritimorpha, is from the Ancient Greek νηρίτης (nērī́tēs 'Nerite') and μορφή (morphḗ 'form').^[2]

Description[edit]

Despite their relatively low diversity, with only around 2,000 species, neritomorphs have achieved a remarkable diversity of forms, resembling a smaller-scale version of the diversity achieved by Gastropoda as a whole.^[3] Terrestrial lifestyles have evolved at least three separate occasions in neritimorphs: the extinct Dawsonellidae and the extant Helicinidae and Hydrocenidae.^[4] Neritimorphs also include the shellless, slug-like Titiscania.^[3]

In all modern neritomorphs except neritopsids, the inner walls of the protoconch are resorbed.^[5]

Unlike most other gastropods, neritomorphs typically have calcified opercula. There is no operculum in the shellless Titiscania, and the Phenacolepadidae have a vestigial, non-calcified operculum that shows no postlarval growth.^[6]

Evolutionary history[edit]

Neritimorpha has an extremely rich geologic history, going back to early Ordovician.^[5] This clade has been considered to be a leftover of early gastropod diversification.

Neritimorpha is the sister taxon of the Apogastropoda.^[7][8] The clade uniting neritimorphs and apogastropods has been called either Adenogonogastropoda^[9] or Angiogastropoda.^[7]

All modern members of Neritimorpha are classified in the order Cycloneritimorpha.^[5] Neritopsoidea was the first of the four modern neritomorph superfamilies to diverge from the others.^[4]

1997 taxonomy[edit]

According to the taxonomy of the Gastropoda (Ponder & Lindberg, 1997) Neritopsina is a gastropod superorder in the subclass Orthogastropoda. The superfamily Palaeotrochoidea is contained within Neritopsina but its order placement is undetermined.

2005 taxonomy[edit]

The taxonomy of the Gastropoda by Bouchet & Rocroi, 2005^[10] categorizes Neritimorpha as a gastropod mollusk clade. It is one of the 6 highest clades in Gastropoda. It contains the clades Cyrtoneritimorpha, Cycloneritimorpha, as well as Paleozoic Neritimorpha of uncertain position.

Clades (and uncertain position taxa) in Neritimorpha include:

• † Paleozoic Neritimorpha of uncertain position
• † clade Cyrtoneritimorpha
• clade Cycloneritimorpha

Four extant superfamilies are recognised: Helicinoidea, Hydrocenoidea, Neritoidea and Neritopsoidea.

In human society[edit]

Nerite snails are popular in the aquarium trade.^[11]

References[edit]