Description

The shell genus, Atys, properly belongs in the family, Haminoeidae, rather than "Atyidae" (which is a classification reserved for a family of crustaceans —not molluscs).  Species in this family are mainly known from the empty shell. In the absence of wet tissue anatomy, most of the species are therefore poorly defined. The shells share many features with shells of other families within the Opisthobranch informal group. Particularly, note the large comma-shaped aperture, and see also the Bullidae and Hydatinidae families. None of these molluscs have an operculum, and shells tend to be rather fragile.

 

The molluscs are colorful. In general, they have a rounded head shield, and fleshy winglike outgrowths (parapodia) that partially or completely fold over the shell, thus providing some protection while burrowing in soft sediments. Certain species of the Hamminoea genus are known to secrete secondary metabolites that have pheromone properties, but not toxin protective functions (Marin et al., 1999). Like the Bullidae, and the Hydatinidae, the Haminoeidae cannot completely retract within their shells.

The Haminoeidae burrow in mud, and in common with the preceding families, they feed predominantly on diatoms and vegetal detritus. However, some degree of opportunism may be exhibited in their feeding habits (Malaquias, 2004).

Classification

Class: Gastropoda

Informal Group : Opisthobranchia

Clade: Cephalaspidea

Subfamily: Haminoeoidea

Family: Haminoeidae

 

Major Genera

• Genus: Atys
• Genus: Haminoea

Atys semistriata (Pease, 1860)
Variably Banded Atys

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