Pyrgiscus fulvocinctus ( Thompson, 1840 )

Høisaeter, Tore, 2014, The Pyramidellidae (Gastropoda, Heterobranchia) of Norway and adjacent waters. A taxonomic review, Fauna norvegica 34, pp. 7-78 : 66-67

Pyrgiscus fulvocinctus ( Thompson, 1840)

Figures 109-110

Turritella fulvocincta Thompson, 1840:98

Chemnitzia fulvocincta (Thompson) - Alder 1848; Forbes & Hanley 1853; Clark 1855

Pyrgulina (Pyrgostelis) fulvocincta (Thompson) - Monterosato 1884

Turbonilla (Pyrgostelis) fulvocincta (Thompson) - Kobelt 1903

Turbonilla (Pyrgisculus) fulvocincta (Thompson) - Winckworth 1932

Pyramis crenatus Brown, 1827:14

Turbonilla crenata (Brown) - Cabioch 1968; Rodriguez Babio & Thiriot-Quièvreux 1975; McKay & Smith 1979; Fretter et al. 1986; Graham 1988; Smith & Heppell 1991; Høisaeter 2009; CLEMAM 2014

Turbonilla (Pyrgiscus) crenata (Brown) - Høisaeter 1986; Smith & Heppell 1991

Pyrgiscus crenatus (Brown) - Schander et al. 2003

Turbonilla rufa (Philippi) - Lovén 1846a, b; Asbjørnsen 1854; G.O. Sars 1878; Appellöf 1897; Grieg 1897, 1898, 1914, 1915; van Aartsen 1981; Öztürk & Bakir 2013

Turbonilla (Pyrgiscus) rufa (Philippi) - Dautzenberg & Fischer 1925

Chemnitzia rufa (Philippi) - Forbes & Hanley 1850 -51; Collin 1880, 1884; Petersen 1888

Odostomia rufa (Philippi) - Jeffreys 1848; M. Sars 1870

Pyrgiscus rufus (Philippi) - Ankel 1936; Thorson 1946

Chemnitzia rufa var. fulvocincta (Thompson) - Norman 1879

Odostomia rufa var. fulvocincta (Thompson) - Jeffreys 1867, 1870; Friele 1874; Jeffreys 1884; Marshall 1900

Turbonilla interrupta (Totten) - McKay & Smith 1979

Turbonilla (Pyrgiscus) interrupta (Totten) - Nordsieck 1972; Høisaeter 1986

Type material: Not known.

Type locality: Presumably Ireland.

Material seen: Norway – North Sea shelf, 9 spms; Skagerrak, 11 spms, 11 shs ; Hordaland, 2 spms, 18 shs; Sogn og Fjordane, 4 shs ( ZMBN 1042 , 4874 ) ; Møre og Romsdal, 3 spms, 4 shs; Nord-Trøndelag, 1 sh; Nordland, 2 spms, 2 shs.

Diagnosis: Shell: Pyrgiscus with elongate, slender, only slightly cyrtoconoid shell. Total shell length not exceeding 11 mm. Number of whorls 12 or less. Shell cream coloured with one or two rufous to tawny bands around periphery, semisolid, semitransparent. Sculpture consisting of 14-18 orthocline ribs, narrower than the interspaces, and six to nine spiral grooves in the interspaces. Whorls evenly rounded, only slightly convex. Protoconch planorboid, only slightly inclined and larger than the other Norwegian species (diameter: 347-389 µm, mean 367 µm). Soft parts: “Body whitish: snout (= mentum) long and bilobed: tentacles leaf-like, rather short and broad, set well apart: eyes small sessile on the inner bases of the tentacles: foot squarish in front, with small angular corners, and pointed behind.” As quoted from Jeffreys (1867) citing Forbes & Hanley (1853). Operculum: Pictured by G.O. Sars (1878).

Biology: Little is known about the biology of this species. It is found on muddy sand bottom at intermediate depths, from ca. 30 m down to at least 150 m. Sometimes found together with Turritella .

Distribution: In Norway reported by G.O. Sars (1878) from Lofoten, but only from a single 8.5 mm long specimen. Also recorded from Trondheimsfjorden, from a single specimen ( Norman 1893). Friele (1874) and Norman (1879) both report it from the Bergen area, Friele states it to be rather common in the area. G.O. Sars also has records from western and southern Norway. In my material, ten specimens from Skagerrak, 14 specimens (of which eight from the North Sea) and an additional 22 shells from the Espegrend area north to Vevelstadsundet (65°42’N, 65- 42 m, sand and shell gravel) and south west of Bodø (67°16’N, 13 m, coarse shell gravel and Laminaria , empty shell). It seems to be most common along the shallow sandy outer fjord bottoms in Møre og Romsdal in Norway. Outside Norway, because of the uncertainty as to the specific distinctness of this species, the southern limits of its distribution are uncertain. It is reported, together with P. rufus , from the eastern coast of Scotland ( McKay & Smith 1979), and also from other North Sea localities. In Scandinavian waters (outside Norway) from Øresund through Kattegatt and Skagerrak ( Petersen 1888). A species called Turbonilla rufa , but from the excellent photographs seem to be indistinguishable from P. fulvocincta , is reported to be the commonest ‘ Turbonilla’ species along the Turkish coasts (Öztürk & Bakir 2013).

Remarks: As is explained in the Remarks for P. rufus above, I think it most likely that this is a species distinct from P. rufus . The few shells of P. rufus I have seen, and the clear statements from Clark (1855), and Forbes & Hanley (1853) support this. The question can only be settled, however, by studying the living specimens and the biology of both forms, or by means of DNA. Although P. fulvocinctus is most variable as regards both the height/width ratio and the development of the coloured band, I consider the extreme forms with more or less uniform brown periostracum and widest shell shape as representatives of P. rufus . The remaining forms are thus all forms of the common Norwegian species P. fulvocinctus . Schander et al. (2003) included specimens of both Pyrgiscus crenatus (= P. fulvocinctus ) and P. rufus in their 16S analysis, both from more or less the same locality on the Swedish west coast. They found the two to agree 100% among the 200 characters unambiguously aligned, although scrutiny of their raw data reveals that there are seven differences (four of them indels) among the 483 characters they had sequenced. Whether the two specimens studied were two extremes of what I have called P. fulvocinctus above, or really one of each species is hard to tell. Jeffreys (1884) claimed that this species is identical to the American P. interruptus (Totten) . Van Aartsen (1981) disagreed with Jeffreys, and regarded P. interruptus as an exotic species, not closely related to the European ones in the P. rufus -complex. P. fulvocinctus is a large and conspicuous species, and in spite of being not particularly abundant, it is one of the more frequently occurring species in Norwegian fauna lists.