''Borsonella hooveri'' is an extinct 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 ...

mollusk in the family

Borsoniidae Borsoniidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Borsoniidae. Accessed through: World Register of Marine Species at http://www.marinespecies.o ...

.Bouchet, P. (2015). Borsonella hooveri (Arnold, 1903). In: MolluscaBase (2015). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=849191 on 2016-02-24

Description

The length of the (decollate) shell, 14.7 mm ; of body whorl, 10 mm; of aperture, 7–5 mm ; max. diam. 8 mm. The small shell is chalky-white, covered with a polished olive-gray

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and ...

. The apex is eroded, leaving indications of about six

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 general form of the shell is biconic with a single sharp keel at the shoulder, between which and the suture the

is more or less excavated. The suture is distinct, the margin in front of it is turgid, giving an effect as if minutely channelled. The excavated area forming the anal fasciole shows arcuate growth lines, crossed by about six faint incised distant spiral lines. The keel somewhat above the periphery, shows a rounded and somewhat compressed edge without waves or nodulations. The surface in front of the keel is moderately convex, spirally sculptured by obsolete distant lines crossed by fine irregular slightly elevated incremental lines, which, in spots, produce a vermiculate aspect. The base of the shell is a little constricted behind the short, nearly straight, attenuated cana. The; body shows a wash of callus. The outer lip has a wide, moderately deep, rounded anal sulcus. In front of the keel it is markedly protractive, thin and simple. The columella is straight, moderately callous, with a single strong almost horizontal plait near its insertion, anteriorly obliquely truncate, twisted, not pervious. The siphonal canal is very short. W.H. Dall (1908): Reports on the Dredging Operations off the West Coast of Central America to the Galapagos, to the West Coast of Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on by the U. S. Fish Commission Steamer "Albatross," during 1891, Lieut. Commander Z. L. Tanner, U. S. N., Commanding. XXX VII. Reports on the Scientific Results of the Expedition to the Eastern Tropical Pacific, in charge of Alexander Agassiz, by the U. S. Fish Commission Steamer "Albatross," from October, 1904, to March, 1905, Lieut. Commander L. M. Garrett, U. S. N., Commanding. XIV. The Mollusca and the Brachiopoda; Bulletin of the Museum of Comparative Zoology at Harvard v. 43 p. 276 (1904)
/ref>

Distribution

This fossil species occurs in the Pleistocene of San Pedro, California.

References

* Arnold, Mem. Cal. Acad. Sci., 1903, 3, p. 201, pl. 10, * McLean J.H. (1996). ''The Prosobranchia''. In: Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and Western Santa Barbara Channel. The Mollusca Part 2 – The Gastropoda. Santa Barbara Museum of Natural History. volume 9: 1–160

External links

*
Bouchet P., Kantor Yu.I., Sysoev A. & Puillandre N. (2011) A new operational classification of the Conoidea. Journal of Molluscan Studies 77: 273–308.
{{DEFAULTSORT:Borsonella Hooveri hooveri Gastropods described in 1903