Lamellitrochus cancapae ( Vilvens & Swinnen, 2007 ) Cavallari & Salvador & Dornellas & Simone, 2019

Cavallari, Daniel C., Salvador, Rodrigo B., Dornellas, Ana P. S. & Simone, Luiz R. L., 2019, Calliostomatidae, Colloniidae, Margaritidae, and Solariellidae (Gastropoda: Trochoidea) collected by the Marion Dufresne (MD 55) expedition in southeastern Brazil, with description of a new species of Calliostoma, Zootaxa 4609 (3), pp. 401-428 : 419

Lamellitrochus cancapae ( Vilvens & Swinnen, 2007) comb. nov.

( Fig. 8 A–C)

Solariella cancapae Vilvens & Swinnen, 2007: 124 , figs 1–2.

Type material. Holotype: RNMH.MOL.109036.

Type locality. Portugal, Azores, east of Flores, CANCAP-V sta. 5171, 39º20’N, 30º53’W, 1874–1887 m .

Previously known distribution. Known only from type locality, 1874–1887 m (empty shells).

New occurrence. Western Atlantic, Brazil, off Espírito Santo, Abrolhos slope, 607–620 m (shells only).

Material examined. Additional material: Brazil: Espírito Santo: off São Mateus, continental slope of Abrolhos , 18°59’S, 37°48’W, MD55 sta. DC73, 607– 620 m, MNHN, 2 sh (27/v/1987). Additional non-MD55 material : Portugal: Azores: holotype .

Measurements. 6¼ whorls, H= 9.1 mm, D=9.0 mm (largest specimen).

Remarks. The species was originally classified in the genus Solariella S. Wood, 1842 , but we propose here a new combination within the Atlantic genus Lamellitrochus . This is justified by the following characters (as defined by Quinn 1991): (1) The angular shell profile formed by a subsutural cord, a peripheral carina and a basal carina, with nearly flat regions between them. The two carinae are fainter in the rounded body whorl of L. cancapae , although they can be easily seen in earlier whorls. (2) A tuberculate subsutural cord. (3) Early whorls sculptured by strong spiral cords and well-marked axial riblets.

The present material compares exceedingly well with the holotype (and only known specimen) of L. cancapae (RMNH.MOL.109036) in overall dimensions, outline with a rounded body whorl ( Fig. 8 A–B), and main spiral sculpture elements (see Vilvens & Swinnen 2007 for a full description). However, the present specimens only show spiral striae on the whorl base ( Fig. 8 C ) and do not have axial sculpture, thus they are lacking the type’s reticulate sculpture pattern; they also lack interumbilical spiral striae. Nevertheless, as seen in other solariellids, the strength of the sculpture can be very variable intraspecifically ( Quinn 1979; Marshall 1999) and thus, the present differences are here interpreted as morphological variation. The present record greatly extends the species range to the Western Atlantic and ca. 6,500 km to the south.

Figures

FIGURE 8. Solariellidae collected by the MD55 expedition. A–C. Lamellitrochus cancapae MNHN, sta. CB73 (H=9.1 mm, D=9.0 mm). A. apertural view. B. apical view. C. umbilical view. D–F. Lamellitrochus pourtalesi. D. MNHN, sta. CB76 (H=5.2 mm, D=5.2 mm), apertural view. E–F. MNHN, sta. CB79, juvenile specimen (H=3.5 mm, D=3.4 mm) under SEM. E. apertural view. F. umbilical view.