Trissexodontidae

Trissexodontidae is a family of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).

Trissexodontidae
Apertural view of the shell of Trissexodon constrictus. Scale is in mm. A regularly ribbed shell is one of the characteristics of this family.
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Order:	Stylommatophora
Suborder:	Helicina
Infraorder:	Helicoidei
Superfamily:	Helicoidea
Family:	Trissexodontidae H. Nordsieck, 1987[1]
Genera
See text
Synonyms[2]
Caracollinini H. Nordsieck, 1987 Oestophorini H. Nordsieck, 1987 Mastigophallini Schileyko, 1991[3] Gittenbergeriinae Schileyko, 1991

This family has no subfamilies.^[2] The family Trissexodontidae was separated out from the families Hygromiidae and Helicodontidae,^[2] and some authors still classify these species within those families.

Distribution

The distribution of Trissexodontidae includes the Iberian Peninsula, northwest Africa,^[4] Azores,^[5] Canary Islands, Madeira and Cape Verde.^[6]

Genera

Genera within the family Trissexodontidae include:

• Caracollina Beck, 1837^[4]
• Gasullia Ortiz de Zárate López, 1962^[4]
• Gasulliella Gittenberger, 1980^[4] - with only one species, Gasulliella simplicula (Morelet, 1845)
• Gittenbergeria Schileyko, 1991^[4]
• Mastigophallus Hesse, 1918^[4] - with only one species, Mastigophallus rangianus (Michaud, 1831)
• Oestophora Hesse, 1907^[4]
• Oestophorella Pfeffere, 1929^[4]
• Trissexodon Pilsbry, 1895^[4] - type genus of the family Trissexodontidae
• Spirorbula Lowe, 1852 - probable classification,^[4] from Madeira and Porto Sancto^[7]
• Suboestophora Ortiz de Zárate López, 1962^[8]

Description

Shells of species in the family Trissexodontidae are flat and regularly ribbed. The periostracum of the shell surface has no hairs.^[4]

A description of the reproductive system was summarized by Prieto et al. (1993).^[4]

In this family, the number of haploid chromosomes is known only for the genus Oestophora (n=30).^[4]