Lamellaria, MONTAGU, 1816

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, Zoological Journal of the Linnean Society 197 (4), pp. 924-964 : 955-956

LAMELLARIA MONTAGU, 1816

( FIGS 2 , 3 , 5F, G , 8C , 9I, J , 10K, L , 11K )

Lamellaria Montagu, 1816 : 184;

type species Lamellaria tentaculata Montagu, 1816 by subsequent designation of Wenz, 1940: 955 as Bulla latens O. F. Muller, 1776 .

Cryptocella H. Adams & A. Adams, 1853: 202 ;

type species Lamellaria tentaculata Montagu, 1816 by subsequent designation of Kobelt, 1876 –1881: 78.

Included species: Lamellaria diegoensis Dall, 1885 , Lamellaria fella (Er. Marcus & Ev. Marcus, 1970) comb. nov., Lamellaria inflata (C. B. Adams, 1852) , Lamellaria latens (O. F. Müller, 1776) , Lamellaria mopsicolor Ev. Marcus, 1958 .

Description: Body of small to medium size for the subfamily, 0.3–1.1 cm total length. Shell thin, weakly calcified; ear shaped, low spire, with expanded aperture; smooth or weakly sculptured by axial growth lines; completely enclosed by the mantle. Periostracum not visible.

Protoconch of 1.1–2.0 whorls; protoconch I 0.56–1.10 whorls, nucleus diameter 125–214 μm, smooth, with subsutural axial folds; protoconch II with or without axial growth lines; protoconch–teleoconch boundary not always distinct.

Mantle flat or dome shaped, outline rounded; thick or thin, rarely with dorsum tubercles; with anterior siphon folds; texture smooth/wrinkled/jelly-like; colour highly variable, almost transparent to white, grey, beige, yellow, orange, red, violet, brown, often patterned with dots or streaks of colour.

Penis to the right of the right cephalic tentacle; with or without a lateral subterminal papilla. Vas deferens with or without a free loop or several folds in the haemocoel.

Radula reduced taenioglossate, with formula 0:1:1:1:0; rachidian tooth base bifurcated; rachidian cusp with few to several small external denticles on the right side only; lateral teeth elongated, composed of an external, pointed and bold cusp without denticles, plus an internal truncated projection, with several small denticles on the distal side.

Jaws short to elongated.

Distribution: Tropical and temperate Eastern Pacific, Tropical Atlantic, north-eastern Atlantic, Mediterranean Sea, North Sea; 0–61 m deep.

Remarks: The genus Lamellaria can be distinguished from the others thanks to the rachidian tooth with a bifurcated base and denticles only on the left side of the cusp and the lateral tooth composed of one cusp and one projection. Species of this genus can be divided in two main lineages: one present in the temperate north-eastern Atlantic and one in the central–western Atlantic tropics and in the tropical and temperate eastern Pacific. Our analyses indicate that the type species, Lamellaria latens , is part of a monophyletic complex of cryptic species (at least four).

We include in this genus Coriocella fella , owing to its characteristic rachidian tooth, unilaterally denticulated, the general shape of the shell and the absence of the typical mantle dorsal warts of Coriocella .

Figures

Figure 2. Phylogenetic relationships of the family Velutinidae (Bayesian tree based on the combined dataset), with clades (A–L) collapsed by genera. Numbers at nodes indicate branch support values [posterior probability (PP) and ultrafast bootstrap (UFb) values, respectively]; support values are shown only when at least one of them is ≥ 80%; white circles at nodes indicate maximum support (PP = 1, Ufb = 100). On the right side of the tree, for each genus is reported a representative photograph of the shell, a schematic representation of the radula, the depth range (in metres) and the geographical distribution.

Figure 3. Phylogenetic relationships of the family Velutinidae (Bayesian tree based on the combined dataset) showing clades A–L expanded. Numbers at nodes indicate branch support values [posterior probability (PP) and ultrafast bootstrap (UFb) values, respectively]; support values are shown only when at least one of them is ≥ 80%; white circles at nodes indicate maximum support (PP = 1, Ufb = 100). Boxes indicate hypothetical species; dashed lines indicate possible alternative species partitions. Coloured boxes on the right indicate genera, and white boxes indicate subfamilies. Letters at the end of sample codes broadly indicate the area of origin:AK, Alaska; ANT, Antarctica; AR, Argentina; BC, British Columbia; BRE, Bretagne; CA, California; CH, China; COR, Corse; CR, Costa Rica; FL, Florida; GF, French Guiana; GP, Guadeloupe; HI, Hawaii; IT, Italy; MG, Madagascar; MQ, Martinique; MX, Mexico; MZ, Mozambique; NC, New Caledonia; NL, Newfoundland; NO, Norway; OR, Oregon; PA, Panama; PF, French Polynesia; PG, Papua New Guinea; PH, Philippines; QLS, Queensland; RE, Reunion; SA, Saudi Arabia; SP, Spain; TAS, Tasmania; TW, Taiwan; VU, Vanuatu; WA, Washington State; ZNZ, Zanzibar.

Figure 5. A, Pacifica lentiginosa sp. nov., MNHN-IM-2009-16140, holotype. B, Pacifica sp. (L18), MNHN-IM-2007-33407. C, Djiboutia sp. (L22), MNHN-IM-2019-9053. D, Coriocella sp., UF-IZ-523481. E, Coriocella sp., MNHN-IM-2019-26097. F, Lamellaria mopsicolor, MNHN-IM-2013-73086. G, Lamellaria latens complex (L41), MNHN-IM-2019-6391. H, Marsenia herberti, MNHN-IM-2019-8219. I, Marsenia perspicua complex (L55), MNHN-IM-2019-13522. Photograph credits: A–C, F, MNHN, Philippe Maestrati; D, Florida Museum of Natural History—Invertebrate Zoology, Gustav Paulay; E, MNHN, Giulia Fassio; G, I, MNHN, Gilles Devauchelle; H, MNHN, Laurent Charles. For the sequenced specimens, the corresponding clade code (see Fig. 3) is reported in parentheses.

Figure 8. Velutinidae shells. A, Djiboutia sp. (L26), MNHN-IM-2019-7668. B, Coriocella sp. (L27), MNHN-IM-2013-84230. C, Lamellaria latens complex (L41), MNHN-IM-2019-14179. D, Marsenia perspicua complex (L55), MNHN-IM-2019-14574. Scale bars: A, C, D, 1 mm; B, 5 mm. For the sequenced specimens, the corresponding species code (see Fig. 3) is reported in parentheses.

Figure 9. Velutinidae protoconchs. A, Marseniopsis conica, BAS 03-764. B, Marsenina rhombica, BAU 4229. C, Calyptoconcha pellucida, BAU 3758. D, Variolipallium cerebroides, NIWA 74086.A. E, Pacifica lentiginosa sp. nov., MNHN-IM-2009-16140, holotype.F, Pacifica sp. (L16), MNHN-IM-2013-58543. G, Djiboutia sp. (L22), MNHN-IM-2019-9053. H, Coriocella sp. (L27), MNHN-IM-2013-84230. I, Lamellaria latens complex (L41), MNHN-IM-2019-14179. J, Lamellaria mopsicolor, MNHN-IM-2013-73086. K, Marsenia perspicua complex (L55), MNHN-IM-2019-14574. L, Marsenia sp. (L42), MNHN-IM-2019-7641. Scale bars: A–L, 500 µm. For the sequenced specimens, the corresponding species code (see Fig. 3) is reported in parentheses. Arrows indicate protoconch I – protoconch II boundary.

Figure 10. Velutinidae radulae. A, Marseniopsis mollis, CE 6137. B, Marsenina rhombica, BAU 4229. C, Velutina cf. coriacea, LACM 182870. D, Calyptoconcha pellucida, BAU 3751. E, Variolipallium regium sp. nov., MNHN-IM-2013-69285, holotype. F, Variolipallium sp. (L10), MNHN-IM-2013-69280. G, Pacifica lentiginosa sp. nov., MNHN-IM-2009-16140, holotype. H, Pacifica sp. (L15), MNHN-IM-2013-59969. I, Djiboutia sp. (L22), MNHN-IM-2019-9053. J, Coriocella sp. (L27), MNHN-IM-2013-84230. K, Lamellaria mopsicolor, MNHN-IM-2013-73086. L, Lamellaria latens complex (L41), MNHN-IM-2019-14113. M, Marsenia herberti, MNHN-IM-2019-8503. N, Marsenia sp. (L45), MNHN-IM-2013-59960. O, Marsenia perspicua complex (L55), MNHN-IM-2019-5980. Scale bars: A–O, 100 µm. For the sequenced specimens, the corresponding species code (see Fig. 3) is reported in parentheses.

Figure 11. Velutinidae jaws. A, M, Marseniopsis mollis, CE 6152. B, N, O, Marsenina rhombica, BAU 2339. C, Limneria prolongata, BAU 4228. D, Calyptoconcha pellucida, BAU 3758. E, Variolipallium regium sp. nov., MNHN-IM-2013-69285, holotype. F, Variolipallium sp. (L10), MNHN-IM-2013-69280. G, Pacifica lentiginosa sp. nov., MNHN-IM-2009-16140, holotype.H, Pacifica sp. (L19), MNHN-IM-2009-16136.I,Djiboutia sp.(L22), MNHN-IM-2019-9053.J,Coriocella cf.jayi (L28), MNHN-IM-2009-16119. K, Lamellaria latens complex (L40), BAU 2536.2. L, Marsenia sp. (L45), MNHN-IM-2013-59960. Scale bars: H, M–O, 100 µm; A–G, I–L, 500 µm. For the sequenced specimens, the corresponding species code (see Fig. 3) is reported in parentheses.