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 (more than half the previous total) 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 (1905–6), 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 (2005).

There are 6 subfamilies in the family Streptaxidae according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, that follows Schileyko (2000):
 * Streptaxinae Gray, 1860 - synonym: Artemonidae Bourguignat, 1889
 * Enneinae Bourguignat, 1883 - synonym: Streptostelidae Bourguignat, 1889
 * Marconiinae Schileyko, 2000
 * Odontartemoninae Schileyko, 2000
 * Orthogibbinae Germain, 1921 - synonyms: Gibbinae Steenberg, 1936; Gonidominae Steenberg, 1936
 * Ptychotrematinae Pilsbry, 1919

2010 taxonomy
Sutcharit et al. (2010) 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
 * Afristreptaxis Thiele, 1932
 * Carinartemis Siriboon & Panha, 2014
 * Discartemon Pfeiffer, 1856
 * Edentulina L. Pfeiffer, 1856
 * Elma Adams, 1866
 * Fischerpietteus Emberton, 2003
 * Glyptoconus Möllendorff, 1894
 * Haploptychius Kobelt, 1905
 * Hypselartemon Wenz, 1947
 * Indoartemon Forcart, 1946
 * Makrokonche Emberton, 1994
 * Martinella Jousseaume, 1887
 * Micrartemon Möllendorff, 1890
 * Nagyelma Páll-Gergely & Hunyadi, 2021
 * Odontartemon L. Pfeiffer, 1856
 * Oophana Ancey, 1884
 * Perrottetia Kobelt, 1905
 * Rectartemon Baker, 1925
 * Sairostoma Haas, 1938
 * Stemmatopsis J. Mabille, 1887
 * Streptartemon Kobelt, 1905
 * Streptaxis Gray, 1837 - type genus of the family Streptaxidae
 * Thachia F. Huber, 2018

Enneinae
 * Austromarconia van Bruggen & de Winter, 2003
 * Avakubia Pilsbry, 1919
 * Conogulella Pilsbry, 1919
 * Costigulella Pilsbry, 1919
 * Dadagulella Rowson & Tattersfield, 2013
 * Digulella F. Haas, 1934
 * Gulella Pfeiffer, 1856 [2]
 * Juventigulella Tattersfield, 1998
 * Microstrophia Möllendorff, 1887
 * Mirellia Thiele, 1933
 * Mirigulella Pilsbry & Cockerell, 1933
 * Paucidentella Thiele, 1933
 * Primigulella Pilsbry, 1919
 * Pseudavakubia de Winter & Vastenhout, 2013
 * Pseudelma Kobelt, 1904
 * Ptychotrema L. Pfeiffer, 1853
 * Pupigulella Pilsbry, 1919
 * Rhabdogulella F. Haas, 1934
 * Silvigulella Pilsbry, 1919
 * Sphincterocochlion Verdcourt, 1985
 * Sphinctostrema Girard, 1894
 * Streptostele Dohrn, 1866
 * Tomostele Ancey, 1885

Marconiinae
 * Gonaxis J. W. Taylor, 1877
 * Marconia Bourguignat, 1889 - type genus of the subfamily
 * Stenomarconia Germain, 1934

Odontartemoninae
 * Artemonopsis Germain, 1908
 * Lamelliger Ancey, 1884
 * Pseudogonaxis Thiele, 1932
 * Tayloria Bourguignat, 1889

Orthogibbinae
 * Acanthennea Martens, 1898 - with the only species Acanthennea erinacea (Martens, 1898)
 * Augustula Thiele, 1931 - with the only species Augustula braueri (Martens, 1898)
 * Careoradula Gerlach & van Bruggen, 1999 - with the only species Careoradula perelegans (Martens, 1898)
 * Edentulina Pfeiffer, 1856
 * Gibbulinella Wenz, 1920
 * † Gibbus Montfort, 1810 - this genus was endemic to Mauritius and it is now extinct
 * Glabrennea
 * Gonaxis Taylor, 1877
 * † Gonidomus Swainson, 1840 - this genus was endemic to Mauritius and it is now extinct
 * Gonospira Swainson, 1840
 * Haploptychius Kobelt, 1905
 * Imperturbatia Martens, 1898
 * Oophana Ancey, 1884
 * Orthogibbus Germain, 1919 - type genus of the subfamily
 * Plicadomus Swainson, 1840
 * Priodiscus Martens, 1898
 * Pseudelma Kobelt, 1904
 * Seychellaxis
 * Silhouettia Gerlach & van Bruggen, 1999 - with the only  species Silhouettia silhouettae (Martens, 1898)
 * Stereostele Pilsbry, 1919 - with the only species Stereostele nevilli (Adams, 1868)

Unsorted to subfamily:
 * Aenigmigulella Pilsbry & Cockerell, 1933
 * Campolaemus Pilsbry, 1892
 * Conturbatia Gerlach, 2001 - with the only species Conturbatia crenata Gerlach, 2001
 * Costigulella Pilsbry, 1919 - formerly included in Gulella
 * † Goniodomulus Harzhauser & Neubauer in Harzhauser et al., 2016
 * Pallgergelyia Thach, 2017
 * Parvedentulina Emberton & Pearce, 2000 - endemic to Madagascar
 * † Pfefferiola Harzhauser & Neubauer, 2021
 * † Protostreptaxis W. Yü & X.-Q. Zhang, 1982
 * Sinistrexcisa De Winter, Gomez & Prieto, 1999 : synonym of Ptychotrema L. Pfeiffer, 1853


 * Notes:
 * Scolodonta Doering, 187 5 used to be classified within Streptaxinae, but Scolodonta is the type genus of the family Scolodontidae.

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 - 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 : 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 : synonym of Gulella (Huttonella) L. Pfeiffer, 1856 represented as Gulella L. Pfeiffer, 1856
 * Idolum L. Pfeiffer, 1856 : synonym of Gonidomus Swainson, 1840 (junior synonym)
 * Indoennea Kobelt, 1904 : synonym of Sinoennea Kobelt, 1904 (junior synonym)
 * Ischnostele C. R. Boettger, 191 5: synonym of Streptostele (Raffraya) Bourguignat, 1883 represented as Streptostele Dohrn, 1866
 * Luntia E.A. Smith, 1898 : synonym of Streptostele (Tomostele) Ancey, 1885 : synonym of Tomostele Ancey, 1885 (junior synonym)
 * Macrogonaxis Bequaert & Clench, 1936 : synonym of Tayloria (Macrogonaxis) Thiele, 1932 represented as Tayloria Bourguignat, 1890
 * Marconia Bourguignat, 1890 : synonym of Gonaxis J. W. Taylor, 1877 (junior synonym)
 * Maurennea: synonym of Gulella (Maurennea) Schileyko, 2000 represented as Gulella L. Pfeiffer, 1856
 * Nevillia E. von Martens, 1880 : synonym of Microstrophia Möllendorff, 1887 (junior homonym of Nevillia H. Adams, 1868 )
 * † Oppenheimiella Pfeffer, 1930 : synonym of † Pfefferiola Harzhauser & Neubauer, 2021 (Invalid: junior homonym of Oppenheimiella Meunier, 1893 [Diptera]; Pfefferiola is a replacement name)
 * Orthogibbus Germain, 1919 : synonym of Gonospira Swainson, 1840
 * Parennea Pilsbry, 1919 : synonym of Ptychotrema (Parennea) Pilsbry, 1919 represented as Ptychotrema L. Pfeiffer, 1853
 * Pseudartemon J. Mabille, 1887 : synonym of Haploptychius Kobelt, 1905
 * Raffraya Bourguignat, 1883 : synonym of Streptostele (Raffraya) Bourguignat, 1883 represented as Streptostele Dohrn, 1866
 * Sinistrexcisa d e Winter, Gómez & Prieto, 1999 : synonym of Ptychotrema L. Pfeiffer, 1853
 * Somalitayloria Verdcourt, 1962 : synonym of Tayloria (Somalitayloria) Verdcourt, 1962 represented as Tayloria Bourguignat, 1890
 * Stenomarconia Germain, 1934 : synonym of Gonaxis (Stenomarconia) Germain, 1934 represented as Gonaxis J. W. Taylor, 1877
 * Thaumatogulella F. Haas, 1951 : synonym of Mirellia Thiele, 1933
 * Varicostele Pilsbry, 1919 : synonym of Streptostele (Varicostele) Pilsbry, 1919 represented as Streptostele Dohrn, 1866
 * Webbia Odhner, 1932 : synonym of Gibbulinella Wenz, 1920