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Taxon profile

species

Pseudorhaphitoma stipendiarii (R.N. Kilburn, 1993)

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Neogastropoda »  family Mangeliidae »  genus Pseudorhaphitoma

Scientific synonyms

Pseudoraphitoma stipendiarii R.N. Kilburn, 1993

Images

Pseudorhaphitoma stipendiarii

Author: Kilburn, R.N.

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Description

Shell narrowly claviform, b/1 0,35-0,38, a/1 0,36-0,39, base rather strongly produced, its termination obliquely truncate and shallowly indented; whorls weakly to fairly strongly convex, with slightly angular periphery; aperture narrow, outer lip with 14-16 weak denticles internally, the posteriormost forming a rounded tubercle which opposes a similar one on the paries; inner lip sometimes with a row of tiny denticles; anal sinus moderately deep; axial ribs rather low, with angular crests, weakly sinuous, continuing onto base of rostrum, 6 per whorl; spiral threads with flat granules that crenulate their edges, 27-33 on penultimate whorl, equally fine on rostrum. Pale flesh-colour, crests of ribs usually with several rows of inconspicuous orange flecks. Protoconch bluntly domed, last whorl bearing weakly arcuate axial riblets, cut into nodules by 5-6 spiral ridges; diameter 0,60-0,70 mm. Maximum length 7,2 mm.
Description: Shell narrowly claviform (b/1 0,35-0,38, a/1 0,36-0,39) with a strongly produced base and blunt, more or less orthoconoid to cyrtoconoid spire; teleoconch whorls about 4,5 in number; suture shallow, inconspicuously undulating, whorl profile weakly to fairly strongly convex with a slightly angular periphery situated at or just below midwhorl, not forming a distinct shoulder; shoulder slope shallowly concave, no subsutural ridge; siphonal canal moderately short, somewhat oblique and wide, its termination obliquely truncate, shallowly indented, left side of base shallowly concave (not notched by rib intervals), fasciole rather weak. Aperture narrow and somewhat sinuously parallel-sided, posterior end pinched into an embayment by opposing parietal and labral nodules, outer lip slightly arched, columella long and straight; labial callus fairly thin, flat and smooth or with a row of small denticles, its outer margin slightly free on columella; parietal callus forming a distinct tubercle a short distance from end; outer lip preceded by a thick, varicoid rib; edge of lip sharp and somewhat incurved, bordered internally by a weak, parallel ridge, which bears 14—16 weak denticles, the posterior one enlarged into a rounded tubercle; lip gently convex in side-view, anal sinus moderately deep and fairly symmetrically U-shaped; stromboid notch slight.
Sculptured by strong but fairly low axial ribs, continuous from whorl to whorl, crossed by very fine, dense spiral lirae, whose summits bear microscopic plicules. Axial ribs narrower than their intervals (which are gently concave, occasionally flattened), their crests angular in T/S, their sides steeply sloping; orientation slightly opisthocline, weakly sinuous, extending strongly from suture-to-suture, on body whorl continuing some distance onto rostrum; 6 axial ribs on all teleoconch whorls. Entire surface covered by thin, close, tabulate spiral lirae, which bear minute, oblique, transverse plicules that serrulate their edges (and render the sutural margin very finely prickly), lirae equal in width to their interstices or wider; 8-12 lirae on 1st teleoconch whorl, penultimate whorl with 27-33, base of body whorl with approximately 40-50 lirae, not becoming coarser on rostrum; under SEM both crests of spirals and their intervals are rugose. Pale flesh-colour, ribs and apex paler, crests of ribs with several rows of very faint orange flecks, one row at midwhorl being the most conspicuous. Protoconch bluntly domed of about 1,6 whorls, nucleus somewhat depressed; initially smooth, then developing axials, on last whorl 16-20 thin, slightly arcuate, orthocline axial riblets, becoming strongly tuberculate on last half whorl, with 5-6 rows of tubercles, of which the median three are the stronger; breadth 0,60-0,70 mm, height 0,42-0,60 mm (b/h 1,17-1,43). Dimensions: 6,1 x 2,3 mm (holotype); 7,2 x 2,5 mm, 5,6 x 2,1 mm (largest and smallest adult paratypes respectively).
Kilburn, R.N., 1993. Turridae (Mollusca: Gastropoda) of southern Africa and Mozambique. Part 7. Subfamily Mangeliinae, section 2.

Interchangeable taxa

The crests of the spiral lirae are similarly pliculate in P. pyramis (Hinds, 1843) from the tropical western Pacific, but the two differ widely in size and relative breadth of shell, and strength of spiral sculpture. Whereas the lectotype of Mangelia maria Thiele, 1925, is identical to Pseudorhaphitoma ichthys (Melvill, 1910) (q.v.), the protoconch of the juvenile paralectotype appears to agree with that of P. stipendiarii, as does its teleoconch sculpture. Confirmation of the occurrence of stipendiarii in East Africa is required from adult shells.
In its naiTOw form and denticulate labrum, P. stipendiarii resembles various western Atlantic mangeliines generally referred to the genus Ithycythara Woodring, 1928, and even its protoconch appears similar to that of Mangilia psila Bush, 1885, type species of the latter genus. However, true Ithycythara appears to lack strong spiral sculpture, other than a peripheral keel and a few indistinct basal threads.
Kilburn, R.N., 1993. Turridae (Mollusca: Gastropoda) of southern Africa and Mozambique. Part 7. Subfamily Mangeliinae, section 2.

Distribution

Inner continental shelf of northern Zululand, 45-60 m, probably north to the Zanzibar/Pemba area.
Kilburn, R.N., 1993. Turridae (Mollusca: Gastropoda) of southern Africa and Mozambique. Part 7. Subfamily Mangeliinae, section 2.
Author: Jan Delsing

Links and literature

EN Galli C.: WMSDB - Wolrdwide Mollusc Species Data Base July 10, 2013 [http://www.bagniliggia.it/WMSD/WMSDhome....] [as Pseudorhaphitoma stipendiarii Kilburn, 1993]
Data retrieved on: 22 November 2013

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