Trochus

Trochus is a genus of medium-sized to large, top-shaped sea snails with an operculum and a pearly inside to their shells, marine gastropod molluscs in the family Trochidae, the top snails.[1]

Trochus
Five views of a shell of Trochus maculatus
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Subclass: Vetigastropoda
Order: Trochida
Superfamily: Trochoidea
Family: Trochidae
Genus: Trochus
Linnaeus, 1758
Species

See text

Synonyms[1]
  • Camelotrochus B. A. Marshall, 1998
  • Infundibulops Pilsbry, 1889
  • Infundibulum (Lamprostoma) Swainson, 1840
  • Lamprostoma Swainson, 1840
  • Polydonta Schumacher, 1817
  • Trochus (Camelotrochus) B. A. Marshall, 1998
  • Trochus (Polydonta) Schumacher, 1817
  • Trochus (Trochus) Linnaeus, 1758
  • Trochus (Zizyphinus) Gray, 1847

When the word "trochus" or "Trochus" is used in reference to fishing sea snails for commercial purposes, the usual species targeted is Tectus niloticus, which is valued for its nacre or mother of pearl layer, which was traditionally made into items such as pearl buttons and jewelry. Tectus niloticus is no longer classified as a Trochus species, and it is no longer classified in the family Trochidae; it is now placed in the family Tegulidae.

History

The name Trochus, according to P. Fischer[2] was used for the first time by Guillaume Rondelet, in 1558, who assembled under this title a rather miscellaneous assortment of univalves. Linnaeus' genus Trochus is composed principally of true Trochidae, but it is now viewed as having contained species of several other very different families.

Lamarck still further restricted the group, by eliminating several genera; and in the 19th century the labors of Gray, H. Adams and A. Adams and others, contributed towards a more systematic arrangement of the family.[3] Further revisions have narrowed down the number of species in this genus, and most names have become synonyms.

Shell description

Sea snails in the genus Trochus have large, thick, solid shells that have a broadly conical spire and a flat base. The periphery is angulated. The base of the shell is flat or convex. The outer and basal lips are smooth within. The columella has a strong fold above, ending in an obtuse tooth below.[3]

The interior of the shell is pearly and iridescent because of a thick layer of nacre (mother of pearl).

Species

Species within the genus Trochus include:[1]

The following species were brought into synonymy:[1]

The following species are nomina dubia (names of unknown or doubtful application)
[1]
  • Trochus bicinctus Philippi, 1849
  • Trochus quadricinctus Mühlfeld, 1824
Species inquirenda
[1]
  • Trochus artensis P. Fischer, 1878
  • Trochus fabrei Montrouzier in Fischer, 1878
  • Trochus incarnatus Philippi, 1846
  • Trochus pulchellus Philippi, 1846
  • Trochus reevei Montrouzier in Souverbie & Montrouzier, 1866
  • Trochus rhodomphalus Souverbie in Souverbie & Montrouzier, 1875
  • Trochus saga Philippi, 1846
  • Trochus scrobiculatus Souverbie in Souverbie & Montrouzier, 1866
  • Trochus sublaevis Geinitz, 1842
  • Trochus subviridis Philippi, 1848

References
  1. Bouchet, P.; Gofas, S. (2010). Trochus Linnaeus, 1758. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138598 on 5 December 2012
  2. P. Fischer. Monog. Genre Troque, in Kiener's Coquilles Vivantes, Paris, 1880.
  3. Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
  • Linnaeus, C. (1758). Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Editio decima, reformata. Laurentius Salvius: Holmiae. ii, 824 pp.
  • A. Adams, Contributions toward a Monograph of the Trochidae, in Proc. Zool. Soc, 1851, pp. 150–192.
  • R- A. Philippi, Monograph of Trochus in Syst. Conchylien Cabinet, ed. 2 (1846 to about 1856).
  • Lovell Reeve, In Conchologia Iconica vol. xiii. (1861) (a very incomplete work)
  • Herbert G.G. (1993). Revision of the Trochinae, tribe Trochini (Gastropoda: Trochidae) of southern Africa. Annals of the natal Museum 34(2):239-308.
  • Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification. Collection Patrimoines Naturels, 50: pp. 180–213

Further reading
  • NZ Mollusca
  • Powell A. W. B., New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1
  • Miller M & Batt G, Reef and Beach Life of New Zealand, William Collins (New Zealand) Ltd, Auckland, New Zealand 1973
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