Streptaxidae


Streptaxidae is a family of carnivorous air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade
Stylommatophora. Six Streptaxidae subfamilies are accepted in the 2005 taxonomy of the Gastropoda by Bouchet & Rocroi.
Streptaxidae are carnivorous except for one species Edentulina moreleti, which is herbivorous. All streptaxids have well-developed radula, except Careoradula perelegans, which is the only known terrestrial gastropod without radula.
Altogether 66 species from the family Streptaxidae are listed in the 2010 IUCN Red List.

Distribution

The historical area of origin of the Streptaxidae is probably Gondwanaland.
The family is widely distributed across the tropical and subtropical areas of South America, Africa and Asia. The Recent native distribution of Streptaxidae includes South America, Africa, Arabia, Madagascar, Seychelles, Mayotte, Comores, Mauritius, Réunion, Rodrigues, India, Sri Lanka, Andamans, South-East Asia and the Philippines. The genus Gibbulinella is found in the Canary Islands.
The species diversity of Streptaxidae reaches its maximum in sub-Saharan Africa.
With 13 genera and about 130 nominal species, the second most diverse streptaxid fauna can be found in Southeast Asia. Streptaxidae are the most diverse among tropical Asian carnivorous snails. In Indochina, streptaxid diversity was thought to comprise only 10 genera and about 40 species in 1967. However, in 2006-2016, 21 new species and one new genus had been described from Indochina. Thirty-seven species are recorded from Thailand, 10 from Myanmar, 45 from Vietnam, and 12 from Laos.

Description

Streptaxids can generally be recognized by their eccentric or cylindrical shells, while the animals have a bright yellow to red or orange body with external hook-like structures on the everted penis.
Early classifications of the family such as Wilhelm Kobelt, used mainly shell shape and the arrangement of apertural dentition. However, many shell characters are highly conserved or occur recurrently, making some species and genera difficult to separate. The reproductive organs of streptaxids can also be taxonomically significant.

Taxonomy

Prior to Schileyko’s revision in 2000 only two subfamilies, the Streptaxinae and the Enneinae had been recognized, which were primarily based on their shell morphology.

2005 taxonomy

Only the one family, Streptaxidae, was recognized within the Streptaxoidea in the taxonomy of Bouchet & Rocroi.
There are 6 subfamilies in the family Streptaxidae according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, that follows Schileyko :
Sutcharit et al. have established a new family Diapheridae within Streptaxoidea and they have added two genera Diaphera and Sinoennea into Diapheridae.
In the recent decades, most of the taxonomic and systematic research on streptaxids has been performed on sub-Saharan African taxa. Only a few publications focus on South American or Asian groups.

Genera

Genera in the family Streptaxidae include:
Streptaxinae
Enneinae
Marconiinae
Odontartemoninae
Orthogibbinae
Ptychotrematinae
Unsorted to subfamily:
Notes: