''Priotrochus obscurus'' 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 Trochidae, the top snails.
;Subspecies:
* ''Priotrochus obscurus obscurus''
(Wood, 1828) (synonyms: ''Gibbula (Priotrochus) sepulchralis''
(Melvill, 1899); ''Gibbula sepulchralis''
(Melvill, 1899); ''Priotrochus sepulchralis''
Melvill, 1899; ''Trochus nabateus''
Issel, 1869; ''Trochus signatus''
Jonas, 1844)
* † ''Priotrochus obscurus ponsonbyi''
(G. B. Sowerby, 1888) (synonyms: ''Monilea (Priotrochus) ponsonbyi''
(G. B. Sowerby, 1888); ''Monilea obscura ponsonbyi'' (G.B. Sowerby, 1888); ''Monilea ponsonbyi''
(G.B. Sowerby, 1888); ''Priotrochus alexandri''
Tomlin, 1926; ''Trochus (Gibbula) ponsonbyi''
G. B. Sowerby, 1888; ''Trochus ponsonbyi''
G.B. Sowerby, 1888)
Description
The shell size varies between 7 mm and 20 mm. The very solid, thick, narrowly perforated shell has a conical shape and is elevated. It is ashen-white, with longitudinal chestnut streaks or maculations. The
spire is elevated. The
apex is acute. The
sutures are slightly impressed, 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 ...
below them closely appressed. The shell contains 6 to 7 whorls. The upper ones are subangular and nodulose in the middle. 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 ...
shows a coronal series of knobs, on large specimens becoming obsolete toward the
aperture. The entire surface is traversed by spiral lirulae, much narrower than the densely obliquely striate interstices. The oblique, ovate aperture is about half the length of shell. The outer
lip is bevelled to an edge. The aperture is spirally lirate. The edge of the
columella is denticulate. Its upper insertion is callous, partly or nearly covering the
umbilicus. Young specimens are subbiangulate with nodulose periphery.
Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
(described as ''Monilea (Priotrochus) obscura'')
Distribution
This species is distributed in the Red Sea and in the Indian Ocean off Madagascar, Mozambique, Tanzania and Durban, South Africa.
References
* Dautzenberg, Ph. (1929). ''Mollusques testacés marins de Madagascar''. Faune des Colonies Francaises, Tome III
* Spry, J.F. (1961). ''The sea shells of Dar es Salaam: Gastropods''. Tanganyika Notes and Records 56
* Herbert D.G. (1988). ''A new species of Priotrochus (Mollusca: Gastropoda: Trochidae) from south-east Africa.'' Annals of the Natal Museum 29(2):503–507
* Herbert D.G. (1994). ''Trochus kotschyi, the first Indian Ocean record of the genus Osilinus (Mollusca: Gastropoda: Trochidae)''. Journal of Zoology 233:345–357.
* Bonfitto A., Sabelli B., Tommasini S. & Herbert D. (1994). ''Marine molluscan taxa from Mozambique described by G.G. Bianconi and preserved in the Zoological Museum of the University of Bologna.'' Annals of the Natal Museum 35:133–138.
* Zuschin, M., Janssen, R. & Baal, C. (2009). Gastropods and their habitats from the northern Red Sea (Egypt: Safaga). Part 1: Patellogastropoda, Vetigastropoda and Cycloneritimorpha. Annalen des Naturhistorischen Museums in Wien 111 73–158. page(s): 104
External links
*
D.G. Herbert, Studies on Priotrochus obscurus and the systematic position of Priotrochus (Mollusca: Gastropoda: Trochidae); Journal of Zoology, 1988 – Wiley Online Library
{{DEFAULTSORT:Priotrochus Obscurus
obscurus
Gastropods described in 1828