Coriocella, BLAINVILLE, 1824

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

CORIOCELLA BLAINVILLE, 1824

( FIGS 2 , 3 , 5D, E , 8B , 9H , 10J , 11J )

Coriocella Blainville, 1824: 259 ;

type species Coriocella nigra Blainville, 1824 by monotypy.

Chelinotus Swainson, 1840: 355 ;

type species: Sigaretus tonganus Quoy & Gaimard, 1832 by monotypy.

Chelyonotus Herrmannsen, 1846: 221 ; unnecessary replacement name for Chelinotus Swainson.

Included species: Coriocella hibyae Wellens, 1991 , Coriocella jayi Wellens, 1996 , Coriocella nigra Blainville, 1824 , Coriocella safagae Wellens, 1999 , Coriocella semperi (Bergh, 1875) , Coriocella tongana (Quoy & Gaimard, 1832) .

Description: Body of small to medium size for the subfamily, 1.5–8.5 cm. Shell thin, strongly to moderately calcified; ear shaped, low spire, with expanded aperture; smooth or weakly sculptured by axial growth lines; completely enclosed by the mantle. Periostracum thin.

Protoconch of 1.0–1.3 whorls; protoconch I 0.46–1.10 whorls, nucleus diameter 122–150 μm, smooth, with subsutural axial folds; protoconch II with or without axial growth lines; protoconch–teleoconch boundary not always distinct.

Mantle dome shaped, outline rounded; thick, with two to six warts on the dorsum; with anterior siphon folds; smooth, wrinkled, often velvet-like in texture; colour highly variable, beige, yellow, red, violet, blue, dark green, brown, black, often patterned with irregular colour patches or spots.

Penis to the right of the right cephalic tentacle; with tip of the seminal duct protruded from the penis tip. Vas deferens without a free loop in haemocoel.

Radula reduced taenioglossate, with formula 0:1:1:1:0; rachidian tooth base bifurcated; rachidian cusp with several external small denticles; lateral teeth elongated, with one external triangular pointed and bold cusp with small denticles on the external side, plus one truncated projection with small denticles on the distal side.

Jaws elongated.

Distribution: Indo-West Pacific ( Madagascar, Reunion, Mauritius, Red Sea, Maldives, Philippines, northern Australia, New Caledonia, French Polynesia, Tonga); 0–18 m deep.

Remarks: Coriocella is probably the lamellarine genus that can be recognized best from the external morphology only, thanks to the presence of a variable, species-specific number of warts, well evident on the dorsum of living animals (e.g. three for Coriocella nigra ; five for Coriocella safage Wellens, 1999 , Coriocella hibyae , Coriocella semperi and Coriocella tongana (Quoy & Gaimard, 1832) ; and six for Coriocella jayi ), and the typical light brown or dark velvet-like coloration. However, the warts can become barely visible and the colour often vanishes once the specimen is preserved in alcohol. The shell shape is hardly distinguishable from the other low-spired lamellariine genera ( Lamellaria , Marsenia and Djiboutia ). However, most adult specimens of Coriocella show a higher level of shell calcification compared with the rest of the subfamily.

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.