Streptaxidae is a family of carnivorous air-breathing land snails, terrestrial pulmonate gastropod mollusks in the clade Stylommatophora.
Streptaxidae are monophyletic while all subfamilies and several genera are polyphyletic.Rowson, Ben. Systematics and diversity of the Streptaxidae (Gastropoda: Stylommatophora): With particular reference to the East African region. Cardiff University (United Kingdom), 2010.
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.IUCN 2010. IUCN Red List of Threatened Species. Version 2010.3. <www.iucnredlist.org>. Downloaded on 27 September 2010.
Distribution The historical area of origin of the Streptaxidae is probably Gondwanaland.Gerlach J. & Bruggen A. C. van (1999). "Streptaxidae Mollusca: Gastropoda: Pulmonata of the Seychelles Islands, western Indian Ocean". Zoologische Verhandelingen 328: 1-60. abstract, PDF.
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 7 subfamilies in the family Streptaxidae according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005, that follows Schileyko (2000):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.
Enneinae Bourguignat, 1883Bourguignat J. R. (1883) Annales des Sciences Naturelles, Zoologie, serie 6, 15, Art. 2: page 74. - synonym: Streptostelidae Bourguignat, 1889 Gulellinae Rowson, 2024 Marconiinae Schileyko, 2000Schileyko 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. Odontartemoninae Schileyko, 2000Schileyko 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. Orthogibbinae Germain, 1921Germain (1921) Faune malacologique terrestre et fluviatile des iles Mascareignes: 415, 461. - synonyms: Gibbinae Steenberg, 1936; Gonidominae Steenberg, 1936 Primigulellinae Rowson, 2024 Streptaxinae Gray, 1860 - synonym: Artemonidae Bourguignat, 1889 Synonyms Ptychotrematinae Pilsbry, 1919: synonym of Enneinae Bourguignat, 1883
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.
The later review "A review of the Diapheridae" in 2020 by Páll-Gergely, B., Hunyadi, A., Grego, J., Sajan, S., Tripathy, B. & Chen, Z.-Y. showed the family Diapheridae to stand separate from Streptaxidae.
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:
Enneinae Avakubia Pilsbry, 1919 Costigulella Pilsbry, 1919 Digulella F. Haas, 1934 Mirigulella Pilsbry & Cockerell, 1933 Paucidentella Thiele, 1933 Pseudavakubia de Winter & Vastenhout, 2013 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
Gulellinae Austromarconia van Bruggen & de Winter, 2003 Dadagulella Rowson & Tattersfield, 2013Dadagulella is placed here, because Dadagulella and Gulella are supposed to be sister groups. Gulella Pfeiffer, 1856 Pseudelma Kobelt, 1904
Marconiinae Gonaxis J. W. Taylor, 1877
Odontartemoninae Artemonopsis Germain, 1908 Lamelliger Ancey, 1884 Pseudogonaxis Thiele, 1932 Tanzartemon Tattersfield & Rowson, 2011 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) Conturbatia Gerlach, 2001 - with the only species Conturbatia crenata Gerlach, 2001 Gerlachina Rowson, 2024 Gibbulinella Wenz, 1920 † Gibbus Montfort, 1810 - this genus was endemic to Mauritius and it is now extinct Glabrennea † Gonidomus Swainson, 1840 - this genus was endemic to Mauritius and it is now extinct Gonospira Swainson, 1840 Imperturbatia Martens, 1898 Orthogibbus Germain, 1919 - type genus of the subfamily Parvedentulina Emberton & Pearce, 2000 - endemic to Madagascar Plicadomus Swainson, 1840 Priodiscus Martens, 1898 Seychellaxis Schileyko, 2000 - with the only species Seychellaxis souleyetianus (Petit, 1841) Silhouettia Gerlach & van Bruggen, 1999 - with the only species Silhouettia silhouettae (Martens, 1898) Stereostele Pilsbry, 1919 - with the only species Stereostele nevilli (Adams, 1868)
Primigulellinae Aenigmigulella Pilsbry & Cockerell, 1933 Juventigulella Tattersfield, 1998 Microstrophia Möllendorff, 1887 Mirellia Thiele, 1933 Primigulella Pilsbry, 1919
Streptaxinae Afristreptaxis Thiele, 1932 Carinartemis Siriboon & Panha, 2014 Discartemon Pfeiffer, 1856 Edentulina L. Pfeiffer, 1856 Elma Adams, 1866 Embertonina Rowson, 2024 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 Pallgergelyia Thach, 2017 Perrottetia Kobelt, 1905 † Protostreptaxis W. Yü & X.-Q. Zhang, 1982 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
Unsorted to subfamily Campolaemus Pilsbry, 1892 † Goniodomulus Harzhauser & Neubauer in Harzhauser et al., 2016 Pallgergelyia Thach, 2017 Panhartemis Siriboon, 2023 † Pfefferiola Harzhauser & Neubauer, 2021
Notes Scolodonta Doering, 1875 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) Conogulella Pilsbry, 1919: synonym of Gulella (Conogulella) Pilsbry, 1919 represented as Gulella L. Pfeiffer, 1856 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, 1915: 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) Marconia Bourguignat, 1889 - type genus of the subfamily: synonym of Gonaxis J. W. Taylor, 1877 (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)