''Halistylus columna'' is a
species of small
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
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
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 ...
mollusk in the
family Trochidae, the top snails.
[Rosenberg, G. (2012). ''Halistylus columna'' (Dall, 1890). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=532895 on 2012-11-23]
Description
The height of the shell attains 5.8 mm, its diameter 1.9 mm. The small, blunt-tipped, polished shell has a subcylindrical shape. it is yellow, brown, salmon-colored, bluish gray, or streaked or banded with these colors. The shell contains seven
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. The
apex is flattish. The small nucleus is not differentiated. The whorls, after the second, are nearly equal in diameter. The
suture is much appressed. The whorl is somewhat constricted in front of it. The
sculpture consists only of faint incremental lines. The base of the shell is rounded. The
aperture is rounded ovate, slightly oblique. The outer
lip is continuous with the
columella, which is raised, arched in harmony with the lip, but not reflected. There is no
umbilicus. The simple
lip is hardly thickened. There is a little callus on the body and in the posterior angle between the lip and body;. The aperture is simple and very slightly pearly. The
operculum is circular, externally shaggy, with many whorls.
The animal has long slender tentacles. The black eyes stand on separate rather long peduncles. The epipodial line is indicated by four or six short stout papillae. The foot is short and broad. The muzzle is rather large and long, a. little indented in the middle line. The median and admedian teethare simple, with narrow straight stems, and simple, wide, mushroom-like cusps. The uncini are numerous and filiform. The admedian teeth number four, the outer ones the larger. The stems and bases of the middle part of the
radula
The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food ...
are so small and thin as to be difficult to distinguish.
Dall, W.H. (1890) Scientific results of explorations by the U.S. Fish Commission Steamer Albatross. No. VII – Preliminary report on the collection of Mollusca and Brachiopoda obtained in 1887–88. Proceedings of the United States National Museum, 12, 219–362, pls. 5–14
/ref>
Distribution
This species occurs in the Atlantic Ocean off Southern Brazil to Argentina at depths between 18 m and 108 m.
References
* Pilsbry, H. A. 1897. ''List of mollusks collected in Maldonado Bay, Uruguay, by Dr. Wm. H. Rush, U. S. N.''; Nautilus 11: 6-9.
External links
To Biodiversity Heritage Library (8 publications)
To Encyclopedia of Life
To ITIS
To World Register of Marine Species
{{Taxonbar, from=Q3738343
columna Columna may refer to:
* ''Columna'' (gastropod) a genus of snails
* ''The Column'' (film), a 1968 Romanian historical film directed by Mircea Drăgan .
* '' Columna Lactaria'' "Milk Column" was a landmark in ancient Rome in the Forum Holitor ...
Gastropods described in 1890