''Agathotoma candidissima'', common name Cox's mangelia, is a species of

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family Mangeliidae.

Description

The length of the shell varies between 4 mm and 11 mm. The white, oblong, turreted shell features 7 to 8

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...

s, with the

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

missing in the specimen described. The axial sculpture comprises 7 to 8 ribs, with a distinctive characteristic where some ribs on the

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

turn abruptly at right angles towards the base of the columella. This feature is especially noticeable on the penultimate and the three or four preceding ribs. Near the top, just below the suture, the ribs are faintly angled. Additionally, faint dots appear on the base in the upper whorls and on the middle and lower parts of the body whorl, which may be easily overlooked. A few faint dots are also present between the ribs, just below the suture. The aperture is elongate-ovate, accounting for approximately 3/7 of the shell's total length. The outer lip is thickened and slightly insinuate at the top. The

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

is short, and the base of the shell is truncated.

Distribution

This species occurs in the Caribbean Sea, the Gulf of Mexico and the Lesser Antilles. Fossils have been found from the

Early Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...

to the Middle Pleistocene in Southern Florida.

References

* Pfeiffer, L. 1840. ''Uebersicht der im Januar, Februar und März 1839 auf Cuba gesammelten Mollusken''. Archiv für Naturgeschichte 6(1) 250-261
C.B. Adams, Specierum novarum conchyliorum, in Jamaica repertorum, synopsis; Proceedings of the Boston Society of Natural History.v. 2 (1845-1848)
* Reeve, L. 1846. ''Monograph of the genus Mangelia.'' Conchologia Iconica 3 pls. 1-8 * Adams, C. B. 1850. ''Descriptions of supposed new species of marine shells, which inhabit Jamaica''. Contributions to Conchology 4 56-68. * Smith, E. A. 1882. ''Diagnoses of new species of Pleurotomidae in the British Museum''. Annals and Magazine of Natural History (5)10 206-218 * Fargo, W. G. 1953. ''Pliocene Mollusca of Southern Florida. Part II. The Pliocene Turridae of Saint Petersburg, Florida''. Monographs of the Academy of Natural Sciences of Philadelphia 18 365-409, pls. 16-24 * Rolán E., Fernández-Garcés E. & Redfern C. (2012) ''New records and description of four new species of the genus Agathotoma (Gastropoda, Mangeliidae) in the Caribbean''. Novapex 13(2): 45-62.

External links

Rosenberg, G., F. Moretzsohn, and E. F. García. 2009. ''Gastropoda (Mollusca) of the Gulf of Mexico'', Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1-1295.
*
Dowgiallo, Michael Joseph. ''Patterns in diversity and distribution of benthic molluscs along a depth gradient in the Bahamas''. Diss. 2004.

De Jong K.M. & Coomans H.E. (1988) Marine gastropods from Curaçao, Aruba and Bonaire. Leiden: E.J. Brill. 261 pp.
{{Taxonbar, from=Q3138643 candidissima Gastropods described in 1845