Calyptoconcha Bouchet & Waren 1993
Creators: name: Fassio, Giulia
name: Stefani, Matteo
name: Russini, Valeria
name: Buge, Barbara
name: Bouchet, Philippe
name: Treneman, Nancy
name: Malaquias, Manuel António E.
name: Schiaparelli, Stefano
name: Modica, Maria Vittoria
name: Oliverio, Marco
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Velutinidae
Calyptoconcha

description: CALYPTOCONCHA BOUCHET & WARÉN, 1993
(FIGS 2, 3, 7A, 9C, 10D, 11D)
Calyptoconcha Bouchet & Warén, 1993: 742.
Type species Lamellaria pellucida A. E. Verrill, 1880, by original designation.
Included species: Calyptoconcha branca (Simone, 2004) comb. nov., Calyptoconcha capensis (Bergh, 1907) comb. nov., Calyptoconcha pellucida (A. E. Verrill, 1880).
Description: Body of small to medium size for the subfamily, 1–4 cm total length. Shell very thin, weakly calcified to membranaceus; ear shaped, high spired with expanded aperture; smooth or weakly sculptured by axial growth lines; completely enclosed by the mantle. Periostracum not visible.
Protoconch of 1.77–1.80 whorls; protoconch I of 0.58–1.00 whorls, smooth, nucleus diameter 54–75 μm; protoconch II with axial growth lines; protoconch– teleoconch boundary not always distinct.
Mantle flat or dome shaped, outline rounded; thick to very thick, with anterior and right lateral siphon folds; texture smooth or wrinkled; colour variability unknown.
Penis to the right of the right cephalic tentacle, with a subterminal lateral papilla. Vas deferens with a free loop in haemocoel.
Radula reduced taenioglossate, formula 0:1:1:1:0; rachidian tooth base squared; rachidian cusp with several small external denticles; lateral teeth elongated, triangular with a single external pointed cusp, with several small denticles on both sides.
Jaws homogeneous, short, with a small vertical protrusion in the centre.
Distribution: Northern temperate Atlantic, Alboran Sea, South Africa, Brazil, Uruguay; 58–4500 m deep.
R e m a r k s: T h e g e n u s C a l y p t o c o n c h a c a n b e distinguished by the combination of a reduced taenioglossate radula (formula 0:1:1:1:0), a rachidian tooth with a squared base, and a non-calcified internal vestigial shell (often broken in dredged specimens and difficult to remove from the body) with a comparatively higher spire. The protoconch is also different from the rest of the subfamily in having a small diameter of the nucleus, a small diameter of the first whorl and lacking subsutural axial folds on protoconch I. The jaws show a diagnostic small vertical protrusion in the centre.
Based on the radular formula, the shape of the rachidian tooth and composition of the shell, we include in this genus the South African Marsenia capensis (Cape Point, 239–1463 m). We also suggest including Lamellaria branca (type locality: Brazil, off Sao Paulo state, in 78 m) based on its radula and shell shape, although the shell seems to be calcified compared with the other two congeners, which might be related to its shallower water habitat.
description: Published as part of Fassio, Giulia, Stefani, Matteo, Russini, Valeria, Buge, Barbara, Bouchet, Philippe, Treneman, Nancy, Malaquias, Manuel António E., Schiaparelli, Stefano, Modica, Maria Vittoria & Oliverio, Marco, 2023, Neither slugs nor snails: a molecular reappraisal of the gastropod family Velutinidae, pp. 924-964 in Zoological Journal of the Linnean Society 197 (4) on pages 951-952, DOI: 10.1093/zoolinnean/zlac091, http://zenodo.org/record/7814306