Pyrgiscus Philippi, 1841

Høisaeter, Tore, 2014, The Pyramidellidae (Gastropoda, Heterobranchia) of Norway and adjacent waters. A taxonomic review, Fauna norvegica 34, pp. 7-78 : 65

Pyrgiscus Philippi, 1841

Type species, by subsequent designation: Melania rufa Philippi, 1836 ; designated by Dall & Bartsch in Arnold (1903:274). Recent, Mediterranean .

Pyramidellids with elongate, conical to cyrtoconoid, many-whorled shells. Sculpture consisting of strong axial ribs with spiral, incised lines in the intercostal grooves, no spiral sculpture crossing the axial ribs. Shell yellowish to reddish brown, sometimes with one to three darker bands round the periphery of each whorl. Columellar fold small to indistinct. Protoconch large, of type A or B. Operculum horny, translucent, thin, without any ‘anchor‘ or internal process, only with a narrow curved list (Figure 112).

This group has traditionally been regarded as a subgenus of Turbonilla , but I consider the distinguishing characters sufficiently distinct to warrant full generic status. This conclusion is supported by the molecular study of Schander et al. (2003) and the morphology based cladistics analysis of Wise (1996). Regarding the nomenclatural history, this group has been blessed with more than its share of problems. Monterosato (1884) recognized 5 sections for the spirally sculptured “ Turbonillas ”, and gave them all new generic names. In particular Pyrgostelis (genotype Melania rufa Philippi, 1836 ) and Pyrgisculus (genotype Melania scalaris Philippi, 1836 ), might both be used for our forms. Dall & Bartsch (1904) largely retained Monterosato’s principles for subdividing the genus Turbonilla s.l., but reintroduced a number of older names. Thus while Pyrgisculus was retained, they renamed Pyrgostelis as Pyrgiscus Philippi, 1841 . Pyrgiscus was introduced by Philippi (1841) for four recent, Mediterranean shells he had described in 1836 as Melania spp. : M. rufa , M. campanellae , M. pallida , and M. scalaris . He did not list the spiral sculpture among the generic characters, and his inclusion of M. campanellae , which is a close relative to, if not conspecific with, Turbonilla lactea shows that he did not regard this as a character worthy of generic distinction. Furthermore, in a footnote, he stated that Risso in 1826 had erected the genus Turbonilla that largely corresponded to Pyrgiscus . Accordingly, most later authors automatically listed Pyrgiscus as a synonym of Turbonilla , until Dall & Bartsch took advantage of the fact that no type species had been designated, reintroduced it as the subgeneric name for one of their striated Turbonilla ’s (see further Iredale 1915:338). Winckworth (1932) use Pyrgisculus Monterosato, 1884 (as a subgenus) with no further explanation. Van Aartsen (1981) and Fretter et al. (1986) use Turbonilla for all species, with or without spiral sculpture. Most recent authors however, use Pyrgiscus as an independent genus. Wharton (1976) suggests that Pyrgiscus may be distinguished from Turbonilla s.s. by the presence of denticles on the penis (as described by Maas 1964 on an unidentified species from the Mediterranean). Except for that I regard the large protoconch and the shell colour as good reasons for keeping the two groups apart. Recently ( Schander et al. 2003) based on 16S mitochondrial DNA-evidence, presented convincing arguments for placing Turbonilla and Pyrgiscus in different clades within the family. Incidentally, Wise (1996) introduced a new genus, Houbrickia , for a North American group with much the same morphological characteristics as our European Pyrgiscus .

Four ‘species’ are treated below although they are not all valid species of the Norwegian fauna. One of the ‘species’ might be a variety of one of the others, while one owes its inclusion to a confusion with a species only living on the Atlantic coasts of France and south into the Mediterranean.