Tomopleura Casey, 1904

Gofas, Serge & Rolán, Emilio, 2009, A systematic review of “ Asthenotoma spiralis (Smith, 1872) ” in West Africa, with description of two new species (Mollusca, Gastropoda, Conoidea), Zoosystema 31 (1), pp. 5-16 : 6-7

Genus Tomopleura Casey, 1904

TYPE SPECIES. — Pleurotoma nivea Philippi, 1851 , by original designation.

REMARKS

“ Pleurotoma ” spiralis has been consistently attributed to the genus Asthenotoma Harris & Burrows, 1891 , in the literature on West African mollusca (e.g., Knudsen 1952, 1956; Collignon 1960; Bassindale 1961; Bernard 1984; Gofas et al. 1985; Rolán & Ryall 1999; Ardovini & Cossignani 2004). Gofas (1990) and Gatto (1997) figured Asthenotoma meneghinii (Mayer, 1868) , a fossil from the European Miocene which is the type species of Asthenotoma . This species has an evenly biconical shell with the last whorl occupying about two-thirds of the total height, has a distinct axial sculpture forming nodes on the spire and last whorl, and has a simple outer lip with a poorly defined labial notch. The lower part of the columella is quite prominent and borders a large, broadly open siphonal canal. The Recent West African species “ Pleurotoma ” lamothei Dautzenberg, 1910 has a quite similar shell architecture although the last whorl is not quite so high, and is possibly a Recent representative of Asthenotoma . Its radula indicates that it belongs to the toxoglossate Conidae but it has a well-developed operculum, which is lacking in “ Asthenotoma ” spiralis . This feature and also the general shell architecture are quite different from the species considered hereafter, which have a high spire and relatively low body whorl, completely lack any element of axial macrosculpture, and have a well-defined labial notch. We consider these sufficient reasons to dismiss the current classification as Asthenotoma .

The attribution to Tomopleura as suggested herein is supported by shell characters and would extend the distribution of the latter genus to the Atlantic. The type species ( Fig. 1 ) is Indo-Pacific but matches the West African species in important details such as the position of the posterior notch, the nonthickened configuration of the outer lip abapically from the notch and the lack of axial folds on the shell. The protoconchs of T. nivea as well as those of the West African species are comparable in being of a multispiral type, and share a smoothish, non-reticulate surface.

Admittedly there are also some differences, in particular, the posterior notch of the outer lip is not so deeply marked in Tomopleura nivea as in the West African species, but we consider that the alternative course of erecting a new genus for the three species treated herein is not appropriate in a paper concerned with the species-level systematics on a local scale, particularly in such a complex family as the Conidae .

Figures

FIG. 1. — Tomopleura nivea (Philippi, 1851), type species of Tomopleura Casey, 1904, neotype (Kilburn 1986), also lectotype of Drillia makimonos Jousseaume, 1883, from Japan (height 27 mm, MNHN).