Odostomia conspicua Alder, 1850

Høisaeter, Tore, 2014, The Pyramidellidae (Gastropoda, Heterobranchia) of Norway and adjacent waters. A taxonomic review, Fauna norvegica 34, pp. 7-78 : 34

Odostomia conspicua Alder, 1850

Figures 49-50

Odostomia conspicua - Alder, 1850:359

Odostomia conspicua Alder - Forbes & Hanley 1850 -51; Jeffreys 1859, 1867, 1869; Marshall 1900; Winckworth 1932; Peñas et al. 1996; Høisaeter 2009; Öztürk et al. 2013

Odostomia (Megastomia) conspicua Alder - Monterosato 1884 ; van Aartsen 1987

Odontostomia (Megastomia) conspicua (Alder) - Dautzenberg & Fischer 1925

Megastomia conspicua (Alder) - Smith & Heppell 1991

Ptychostomon conspicuum (Alder) - Kobelt 1903

Chemnitzia acuta Clark (in part) - Clark 1855

Type material: Lectotype (?) USNM 133036 “Fig’d type in Br. Conch. ” 8.5 mm (van Aartsen 1987).

Type locality: Douglas , Isle of Man ?

Material seen: Norway - Skagerrak, 9 spms, 3 shs.

Diagnosis: Shell: An elongated and large (reported to reach 9 mm, van Aartsen 1987) sometimes somewhat asymmetrical cone. Prosocline growth lines; keel-like angulation of periphery of body whorl (especially on younger specimens). Aperture rhomboidal. Protoconch large and with nucleus completely exposed. Soft parts: (in conserved specimen) uniform yellowish white, as opposed to O. unidentata which has a profusion of lead-gray pigmentation, and O. acuta with purplish brown pattern. Eyes very large and farther apart than in any other Norwegian species of the family. Operculum: Not studied.

Biology: Not known.

Distribution: In Norway reported from the Skagerrak (Loshavn, Vest Agder, 58°03’N, 06°49’E, 35-55 m) by G.O. Sars (1878). In my material from Skagerrak, ten samples with nine specimens and some shells. Not found further north along the coast. Outside Norway it is known from Bohuslän, Shetland ( Jeffreys 1867); possibly from the Scottish North Sea coast, ( Jeffreys 1867; McKay & Smith 1979); from Orkneys and Shetland south along the west coast of Europe to the Mediterranean, and a few records from Madeira and the Canary Islands ( Fretter et al. 1986, Peñas 1996, van Aartsen et al. 1998, Öztürk et al. 2013).

Remarks: My specimens from the Skagerrak, ranging in size from 2.5 to 4.75 mm, mostly fit the description of O. conspicua as found in Fretter et al. (1986) and Peñas et al. (1996). The similarity to the type specimen (USNM 133036) illustrated in van Aartsen (1987) is not convincing, but this specimen is very large, c. 8.5 mm long with eight teleoconch whorls. A characteristic feature of my shells is the slow increase in the diameter of the first couple of whorls, giving the spire an almost double concave outline. The colour of one of the specimens is slightly reddish (periostracum), but the other two are translucent yellowish-grey. The immediate impression is that the protoconch is very large, but this may be because it is placed very high and free on top of the whorls, and the first teleoconch whorl is rather narrow (Figure 50). Measurements show the protoconch to be only slightly larger than the one of O. unidentata , which, however is more immersed in the first teleoconch whorl.