Altogether 66 species from the family Streptaxidae are listed in the 2010 IUCN Red List.[5]
Distribution
The historical area of origin of the Streptaxidae is probably Gondwanaland.[6]
The family is widely distributed across the tropical and subtropical areas of South America, Africa and Asia.[7] 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.[2] The genus Gibbulinella is found in the Canary Islands.[2]
The species diversity of Streptaxidae reaches its maximum in sub-Saharan Africa.[7]
With 13 genera and about 130 nominal species, the second most diverse streptaxid fauna can be found in Southeast Asia.[7] Streptaxidae are the most diverse among tropical Asian carnivorous snails.[7] In Indochina, streptaxid diversity was thought to comprise only 10 genera and about 40 species in 1967.[8] However, in 2006–2016, 21 new species (more than half the previous total) and one new genus had been described from Indochina.[8] Thirty-seven species are recorded from Thailand, 10 from Myanmar, 45 from Vietnam,[8][9] and 12 from Laos.[8]
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.[7]
Early classifications of the family such as Wilhelm Kobelt (1905–6), used mainly shell shape and the arrangement of apertural dentition.[8] However, many shell characters are highly conserved or occur recurrently, making some species and genera difficult to separate.[8] The reproductive organs of streptaxids can also be taxonomically significant.[8]
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.[7]
Sutcharit et al. (2010)[2] have established a new family Diapheridae within Streptaxoidea and they have added two genera Diaphera and Sinoennea into Diapheridae.[2]
In the recent decades, most of the taxonomic and systematic research on streptaxids has been performed on sub-Saharan African taxa.[7] Only a few publications focus on South American or Asian groups.[7]
Scolodonta Doering, 1875 used to be classified within Streptaxinae,[2] but Scolodonta is the type genus of the family Scolodontidae.[10]
Synonyms
Subfamily Gibbinae Steenberg, 1936: synonym of Orthogibbinae Germain, 1921
Subfamily Gonidominae Steenberg, 1936: synonym of Orthogibbinae Germain, 1921
Subfamily Ptychotrematinae Pilsbry, 1919: synonym of Enneinae Bourguignat, 1883
Aberdaria Blume, 1965: synonym of Primigulella Pilsbry, 1919 (junior synonym)
Acanthenna: synonym of Acanthennea E. von Martens, 1898 (misspelling)
Adjua Chaper, 1885: synonym of Ptychotrema (Adjua) Chaper, 1885 represented as Ptychotrema L. Pfeiffer, 1853 (original rank)
Alcidia Bourguignat, 1890: synonym of Streptaxis Gray, 1837
Artemon H. Beck, 1837: synonym of Streptaxis Gray, 1837
Campylaxis Ancey, 1888: synonym of Streptostele Dohrn, 1866
Carychiopsis E. von Martens, 1895: synonym of Ennea H. Adams & A. Adams, 1855: synonym of Ptychotrema (Ennea) H. Adams & A. Adams, 1855 represented as Ptychotrema L. Pfeiffer, 1853
Colpanostoma Bourguignat, 1890: synonym of Tayloria (Tayloria) Bourguignat, 1890 represented as Tayloria Bourguignat, 1890 (junior synonym)
Ennea H. Adams & A. Adams, 1855[2] - type genus of the subfamily : synonym of Ptychotrema (Ennea) H. Adams & A. Adams, 1855 represented as Ptychotrema L. Pfeiffer, 1853
Enneastrum L. Pfeiffer, 1856: synonym of Ennea H. Adams & A. Adams, 1855: synonym of Ptychotrema (Ennea) H. Adams & A. Adams, 1855 represented as Ptychotrema L. Pfeiffer, 1853
Eustreptaxis L. Pfeiffer, 1878: synonym of Streptaxis Gray, 1837 (objective junior synonym)
Eustreptostele Germain, 1915: synonym of Streptostele (Tomostele) Ancey, 1885: synonym of Tomostele Ancey, 1885
Gibbonsia Bourguignat, 1890: synonym of Gigantaxis Tomlin, 1930: synonym of Tayloria (Tayloria) Bourguignat, 1890 represented as Tayloria Bourguignat, 1890 (junior primary homonym of Gibbonsia Cooper, 1864)
Gibbulina Beck, 1837: synonym of Gibbus Montfort, 1810 (invalid; unnecessary replacement name for Gibbus Monfort, 1810)
Gigantaxis Tomlin, 1930:[2] synonym of Tayloria (Tayloria) Bourguignat, 1890 represented as Tayloria Bourguignat, 1890
Haplonepion Pilsbry, 1919: synonym of Ptychotrema (Haplonepion) Pilsbry, 1919 represented as Ptychotrema L. Pfeiffer, 1853
Huttonella Pfeiffer, 1855:[2] synonym of Gulella (Huttonella) L. Pfeiffer, 1856 represented as Gulella L. Pfeiffer, 1856
Idolum L. Pfeiffer, 1856: synonym of Gonidomus Swainson, 1840 (junior synonym)
^Schileyko A. A. (2000). "Treatise on recent terrestrial pulmonate molluscs: Rhytididae; Chlamydephoridae; Systrophiidae; Haplotrematidae; Streptaxidae; Spiraxidae; Oleacinidae; Testacellidae". Ruthenica Supplement 2 Part 6: 731–880.
^Bourguignat J. R. (1883) Annales des Sciences Naturelles, Zoologie, serie 6, 15, Art. 2: page 74.
^Schileyko A. A. (2000). "Treatise on recent terrestrial pulmonate molluscs: Rhytididae, Chlamydephoridae, Systrophiidae, Haplotrematidae, Streptaxidae, Spiraxidae, Oleacinidae, Testacellidae". Ruthenica, Suppl. 2, Part 6: 731-880. page 828.
^Schileyko A. A. (2000). "Treatise on recent terrestrial pulmonate molluscs: Rhytididae, Chlamydephoridae, Systrophiidae, Haplotrematidae, Streptaxidae, Spiraxidae, Oleacinidae, Testacellidae". Ruthenica, Suppl. 2, Part 6: 731-880. page 830.
^Germain (1921) Faune malacologique terrestre et fluviatile des iles Mascareignes: 415, 461.
^Pilsbry, H. A. (1919). "A review of the land mollusks of the Belgian Congo : chiefly based on the collections of the American Museum Congo Expedition, 1909-1915". Bulletin of the American Museum of Natural History. 40: 180.
^Bequaert, J.; Clench, W. J. (1936). ""Studies of African land and fresh-water mollusks. Notes on Gonaxis Taylor, with description of a new species"". Journal of Conchology. 20. London: 263–273.
Further reading
Zilch, A (1961). "Die Typen und Typoide des Natur-Museums Senckenberg 24: Mollusca, Streptaxidae". Archiv für Molluskenkunde. 90: 79–120.
