''Nquma rousi'' 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 ...
mollusk in the
family Horaiclavidae
Horaiclavidae is a family of predatory sea snails, marine gastropod mollusks in the superfamily Conoidea.
In 2011 this family was split off from the family Pseudomelatomidae (formerly the subfamily Crassispirinae McLean, 1971) by Bouchet P., Ka ...
.
Description
The length of the shell attains 17 mm.
The shell is broadly fusiform. The posterior two-fifths of the
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 between the sutures shows a strongly excavated channel. The anterior three-fifths are marked by 10–12 prominent, broad, low, rounded, somewhat protractive axial ribs which are truncated posteriorly by the channel, their terminations forming cusps. The intercostal spaces are about twice as wide as the ribs. The ribbed portions of the whorls on the
spire are covered by five, equal and equally spaced, incised, spiral lines. The summit of the whorls are appressed, rendering the sutures ill-defined. The base of 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 ...
is moderately long, marked by the feeble continuations of the axial ribs and on the posterior half by five incised spiral lines equaling those on the spire in strength and spacing and forming a continuous series with them. The anterior portion of the base shows about seven ill-defined spiral lirations. The
aperture is narrowly elongate pyriform. The sinus is shallow immediately below the sutures. The outer
lip is somewhat sinuous. The
columella is strong, slightly sigmoid. The coloration of the type consists of a creamy white ground, which is almost unmarked in the subsutural channel and on the anterior half of the base on the last turn. A few dots of brownish orange appear near the summit between the ribs of the preceding whorls. The ribbed portion of the whorl between the anterior and posterior portion of the base is strongly mottled with brownish orange in the intercostal spaces, less so on the summits of the ribs, while a little posterior to the middle the base is marked by two slender spiral lines of the same color.
P. Bartsch (1915), Report on the Turton collection of South African marine mollusks, with additional notes on other South African shells contained in the United States National Museum; Bulletin of the United States National Museum v. 91 (1915)
(described as ''Clionella elizabethae'')
Distribution
This marine species occurs off Cape Agulhas to Southern KwaZulu-Natal
KwaZulu-Natal (, also referred to as KZN and known as "the garden province") is a province of South Africa that was created in 1994 when the Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu) and Natal Province were merged. It is locate ...
, South Africa; also off Southern Madagascar.
References
* Steyn, D.G. & Lussi, M. (1998) ''Marine Shells of South Africa. An Illustrated Collector’s Guide to Beached Shells.'' Ekogilde Publishers, Hartebeespoort, South Africa, ii + 264 pp. page(s): 154
External links
Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295.
*
Specimen at MNHN, Paris
{{DEFAULTSORT:Nquma Rousi
rousi
Gastropods described in 1886