Turbinella pyrum (Linné, 1767)

Turbinella pyrum (Linné, 1767)

Trawled on mud bottom in shallow water off Jaffina, Palk Strait, Sri Lanka (93 mm.)

Turbinella pyrum (Linné, 1767)

Off India (100 mm.)

This form pictured immediately above has been named Turbinella rapa Lamarck, 1816 and T. pyrum (Linné, 1767) variety obtusa Hornell, 1916.

Heavy, broad chanks, presumably from the Indian subcontinent, were described by Lamarck as T. rapa (1816) and T. napus (1822). Examination of the type illustrations suggests that the two are intermediate in shape between T. pyrum (Linné, 1767)  and T. ponderosa (Lightfoot, 1786), T. rapa being higher spired and having a longer siphonal canal than T. napus.

A very interesting study of the zoogeographic and ecophenotypic variation of Turbinella pyrum from S.E. India and Sri Lanka by Hornell (1916) provides critical insights into the diversity of shell form in this chank. Clear evidence for geographical as well as ecological influence on shell form is presented. Hornell's rather unwieldy and unorthodox system of four eco-geographic varieties is actually quite applicable. Although he apparently misinterpreted T. rapa Lamarck (equal to his "var. obtusa"), ill-advisedly sunk into the nominate species under his "var obtusa," and split what he admitted were bathymetric variants of a geographically distinct entity as vars. comorinensis and globosa, he provides a basis for viewing the Indian Chanks as three geographic subspecies: T. pyrum pyrum (Linné, 1767), [synonym T. napus Lamarck, 1822] north of Adam's Bridge, (archipelago connecting India and Sri Lanka); the high-spired T. pyrum rapa Lamarck, 1816 south of the Bridge; and T. pyrum ponderosa (Lightfoot, 1786) forty miles east and west of Cape Cormorin at the southern tip of India.

Anon. 1957.  Opinion 479.  Opin. Int. Comm. Zool. Nomencl. 16:365-456.
Dall, W.H. 1921.  Species named in the Portland Catalogue.  Nautilus 34: 97-100; 123-132 (January; April).
Dance, S.P. 1966.  Shell collecting, an illustrated history. Univ. of California, Berkeley, 344p., 35pls.
Dillwyn, L.W. 1817.  A descriptive catalogue of Recent shells, (2 vols.).  London, xii, 1092p.
Dodge, H. 955.  A historical review of the mollusks of Linnaeus.  Part 3. The genera Bulla and Voluta of the class Gastropoda. Bull. A.M.N.H. 107(1):5-157.
Gmelin, J.F. 1791.  Systema naturae, ed.13, vol.1, part 6, p.3021-3909.
Hornell, J. 1916.  The Indian varieties and races of the genus TurbinellaMem. Ind. Mus. 6:109-125, 3pls.
Lamarck, J.B.P.A. de M.de. 1792.  Journal d'histoire naturelle (choix de mémoires...). Paris, 2 vols. [not seen].
_____ 1816.  Tableau encyclopédique et méthodique...Paris, vol.2, p.1-16; vol.3, pls.391-488.
_____ 1822.  Histoire naturelle des animaux sans vertèbres. Paris, vol.7, 711p.
[Lightfoot, J.] 1786.  A catalogue of the Portland Museum, lately the property of the Dutchess Dowager of Portland, deceased, which will be sold at auction.... London, viii + 194p. [brackets around author's name connote original Martini, F.W.  and J.H. Chemnitz. 1769-1795.  Neues systematisches Conchylien-Cabinet....11vols.  Nuremburg, numerous p., 406pls. [only illustrations were consulted.] [All plates with annotations reprinted in Tryonia No. 2, parts 1,2, 427p., 432pls., 70vigns., August 1, 1979.]
Martyn, T. 1784-87.  The universal conchologist....2 (some 4) vols.  London, 27p., 80pls. [not seen].
Pilsbry, H.A. 1889.  Manual of conchology;  structural and systematic....Vol.5 (Second series) A.N.S.P., Philadelphia, 216p.,
Reeve, L. 1847.  Monograph of the genus Turbinella.  13 pls. and text, in Conchologia Iconica Vol.4, London.
Rehder, H.A. 1967.  Valid zoological names of the Portland Catalogue.  Proc. U.S.N.M. 121(3579):1-51.
Röding, P.F. 1798.  Museum Boltenianum.  Hamburg, viii, 199p. [Reprinted by facsimile by Sherborn and Sykes (1906) and again by A.M.U. (1986)].
Rose, K. 1974.  The religious use of Turbinella pyrum (Linnaeus), the Indian Chank. Nautilus 88(1):1-5 (Jan.).