Trochidae

The Trochidae, common name top snails, are a taxonomic family of very small to large sea snails, marine gastropod molluscs in the clade Vetigastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi from 2005).

This family is commonly known as the "top snails", because in many species the shell is shaped like an old-fashioned top. They are characterized by some primitive traits among the opisthobranchs : a heart with two atriums and external fertilization. They have retained only one kidney and the second osphradium has been lost in the course of evolution. They have a corneous operculum which fits the aperture snugly.

Contents 1 Taxonomy 1.1 2005 taxonomy 1.2 2008 taxonomy 1.3 2010 taxonomy 2 Distribution 3 Ecology 3.1 Habitat 3.2 Life cycle 3.3 Feeding 4 Genera 5 Unassigned 6 Subfamily ? 7 References

Taxonomy

2005 taxonomy

This family consists of six following subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005):

• Trochinae Rafinesque, 1815
  • tribe Trochini Rafinesque, 1815 - synonym: Pyramidinae Gray, 1847
  • tribe Cantharidini Gray, 1857
  • tribe Monodontini Gray, 1857 - synonym: Gibbulinae Stoliczka, 1868
• Halistilynae Keen, 1958
• Lirulariinae Hickman & McLean, 1990
• Margaritinae Thiele, 1924
  • tribe Margaritini Thiele, 1924 - synonym: Margaritinae Stoliczka, 1868 (inv.)
  • tribe Gazini Hickman & McLean, 1990
  • tribe Kaiparathinini Marshall, 1993
• Stomatellinae Gray, 1840 - synonyms: Stomatiidae Carpenter, 1861, Stomatellidae Gray, 1840
• Umboniinae H. Adams & A. Adams, 1854 (1840)
  • tribe Umboniini H. Adams & A. Adams, 1854 (1840) - synonym: Rotellinae Swainson, 1840
  • tribe Bankiviini Hickman & McLean, 1990
  • tribe Isandini Hickman, 2003
  • tribe Talopiini Finlay, 1928 - synonym: Monileini Hickman & McLean, 1990

2008 taxonomy

The family Trochidae was redefined according to Williams et al. (2008).^[2] The tribes from Trochinae were raised to subfamilies,^[2] Margaritinae was moved to the family Turbinidae,^[2] and Halistylinae provisionally stays in Trochidae.^[2]

• Trochinae Rafinesque, 1815
• Cantharidinae Gray, 1857
• Monodontinae Gray, 1857
• Halistylinae Keen, 1958
• Lirulariinae Hickman & McLean, 1990
• Stomatellinae Gray, 1840
• Umboniinae H. Adams & A. Adams, 1854 (1840) - tribes of Umboniinae are retained the same as in taxonomy of the Gastropoda by Bouchet & Rocroi (2005)
  • tribe Umboniini H. Adams & A. Adams, 1854 (1840) - synonym: Rotellinae Swainson, 1840
  • tribe Bankiviini Hickman & McLean, 1990
  • tribe Isandini Hickman, 2003
  • tribe Talopiini Finlay, 1928 - synonym: Monileini Hickman & McLean, 1990

2010 taxonomy

Williams et al. (2010)^[1] added three new subfamilies to Trochidae : Alcyninae, Fossarininae and Chrysostomatinae. The subfamily Lirulariinae is now incorporated within the subfamily Umboniinae. In this study was also shown that the subfamily Margaritinae is not monophyletic. Here is also shown, which genera were placed into these three new subfamilies:^[1]

• subfamily Alcyninae Williams, Donald, Spencer & Nakano, 2010 - only one genus Alcyna
• subfamily Trochinae Rafinesque, 1815
• subfamily Monodontinae Gray, 1857
• subfamily Fossarininae Bandel, 2009
• subfamily Chrysostomatinae Williams, Donald, Spencer & Nakano, 2010
  • genus Chrysostoma
  • genus Chlorodiloma
• subfamily Umboniinae H. Adams & A. Adams, 1854 (1840) - synonym: Lirulariinae Hickman & McLean, 1990
• subfamily Stomatellinae Gray, 1840
• subfamily Cantharidinae Gray, 1857
• subfamily Halistylinae Keen, 1958

Distribution

This family has a worldwide distribution in tropical, temperate and arctic waters. Members of this family are among the most common marine snails along the rocky shores of Europe.

Ecology

Habitat

Many species in the family live either in the intertidal zone or in the shallow subtidal zone, but some live in deeper water. They are usually abundant on solid substrate, like rocky shores and reefs.^[3]

Life cycle

The Trochidae are dioecious, and the fertilization occurs internally.^[3] Top snail eggs are laid individually or in gelatinous egg masses in the water. Individuals may hatch as free-swimming planktonic larvae or juvenile crawlers.^[3]

Feeding

This family of snails feed by grazing on algae and detritus, and more rarely by filter-feeding, as observed in the genus Umbonium.^[3]

Genera

Genera within the family Trochidae include:

Alcyninae

• Alcyna - type genus of the subfamily Alcyninae, it is also the only genus in this subfamily

Cantharidinae Gray, 1857

• Agagus Jousseaume, 1894
• Calliotrochus P. Fischer, 1879
• Calthalotia Iredale, 1929 ref> Bouchet, P. (2010). Calthalotia Iredale, 1929. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=512278 on 2010-10-31 </ref>
• Cantharidella Pilsbry, 1889^[4]
• Cantharidus Montfort, 1810^[5]
• Clelandella Winkworth, 1932 - Clelandella is a junior synonym of Jujubinus Monterosato, 1884 according to Backeljau (1986) and Vaught (1989).^[6]
• Gibbula Risso, 1826^[7]
• Jujubinus Monterosato, 1884^[8]
• Kanekotrochus Habe, 1958
• Komaitrochus Kuroda & Iw. Taki, 1958
• Nanula Thiele, 1924
• Odontotrochus P. Fischer, 1880
• Osilinus Philippi, 1847^[9]
• Oxystele Philippi, 1847^[10]
• Phasianotrochus Fischer, 1885
• Phorcus^[11]
• Pictodiloma Habe, 1946
• Priotrochus P. Fischer, 1879
• Prothalotia Thiele, 1930
• Pseudotalopia Habe, 1961^[12]
• Thalotia Gray, 1840^[13]
• Tosatrochus MacNeil, 1961
• Trochinella Iredale, 1937

Chrysostomatinae

• Chlorodiloma Pilsbry, 1889
• Chrysostoma Swainson, 1840

† Eucyclinae

Fossarininae Bandel, 2009

• Broderipia Gray, 1847
• Clydonochilus P. Fischer, 1890 - probable placement by Williams et al. (2010)^[1]
• Fossarina A. Adams & Angas, 1864
• Minopa Iredale, 1924 - probable placement by Williams et al. (2010)^[1]
• Synaptocochlea Pilsbry, 1890^[14]
• “Roya” eximia

Halistylinae

• Botelloides Strand, 1928
• Charisma Hedley, 1915
• Halistylus Dall, 1890

Monodontinae

• Austrocochlea P. Fischer, 1885
• Diloma Philippi, 1845^[15]
• Monodonta Lamarck, 1799

Stomatellinae

• Gena Gray, 1840^[16]
• Microtis H. Adams & A. Adams, 1850
• Pseudostomatella Thiele, 1921^[17]
• Stomatella Lamarck, 1816^[18]
• Stomatia^[19]
• Stomatolina^[20]

Trochinae 

• Clanculus Montfort, 1810^[21]
• Coelotrochus P. Fischer, 1879
• Eurytrochus P. Fischer, 1879
• Infundibulops Pilsbry, 1889
• Infundibulum Montfort, 1810
• Notogibbula Iredale, 1924
• Pulchrastele Iredale, 1929
• Rubritrochus L. Beck, 1995
• Trochus Linnaeus, 1758

Umboniinae - synonyms: Lirulariinae, tribe Bankiviini, tribe Isandini, tribe Talopiini and tribe Umboniini.

• Antisolarium Finlay, 1927
• Archiminolia Iredale, 1929
• Bankivia Beck In Krauss, 1848
• Camitia H. Adams & A. Adams, 1854
• Conotalopia Iredale, 1929
• Ethalia H. & A. Adams, 1854^[22]
• Ethaliella Pilsbry, 1905^[23]
• Ethminolia Iredale, 1924^[24]
• Isanda H. Adams and A. Adams, 1854^[25]
• Leiopyrga H. Adams & A. Adams, 1863
• Lirularia Dall, 1909^[26]
• Monilea Swainson, 1840^[27]
• Parminolia Iredale, 1929
• Pseudominolia Herbe, 1992^[28]
• Rossiteria Brazier, 1895^[29]
• Sericominolia Kuroda & Habe, 1954
• Umbonium Link, 1807^[30]
• Vanitrochus^[31]
• Zethalia Finlay, 1926

---

Other genera within the family Trochidae include^[32][33][34]:

Unassigned

• Callumbonella Thiele, 1924^[35]
• Enida A. Adams, 1860
• Intortia Egorova, 1972
• Labio Gray, 1850
• Tropidomarga Powell, 1951
• Umbonella A. Adams, 1863

Subfamily ?

• Ilanga Herbert, 1987
• Micrelenchus Finlay, 1926^[36] : synonym of Cantharidus Montfort, 1810
• Olivia Cantraine, 1835
• Phorculus Cossmann, 1888
• Planitrochus Perner, 1903
• Talopena Iredale, 1918
• Thaltia
• Thoristella Iredale, 1915^[37]
• Turcicula Dall, 1881^[38] : synonym of Lischkeia P. Fischer, 1879

References

• Williams S.T., Donald K.M., Spencer H.G. & Nakano T. (2010) Molecular systematics of the marine gastropod families Trochidae and Calliostomatidae (Mollusca: Superfamily Trochoidea). Molecular Phylogenetics and Evolution 54:783-809