Hyalorisia kely Fassio, Bouchet & Oliverio, 2020

Fassio, Giulia, Russini, Valeria, Buge, Barbara, Schiaparelli, Stefano, Modica, Maria Vittoria, Bouchet, Philippe & Oliverio, Marco, 2020, High cryptic diversity in the kleptoparasitic genus Hyalorisia Dall, 1889 (Littorinimorpha: Capulidae) with the description of nine new species from the Indo-West Pacific, Journal of Molluscan Studies (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen) 86 (4), pp. 401-421 : 416

Hyalorisia kely Fassio, Bouchet & Oliverio new species

MOTU-7 ( Figs 3G , 5C , 7F, O )

Type material: Holotype: off Mahajanga, NW Madagascar, MIRIKY, Stn CP3268 , 15°31 S, 45°45 E, 640–800 m, MNHN-IM-2007-39091 (male).

Material examined: The holotype and other material (MNHN-IM-2007-38809 and MNHN-IM-2007-39041).

Etymology: After the Malagasy adjective ‘kely’, meaning ‘little or small’, referring to the size of this species.

ZooBank registration: urn:lsid:zoobank.org:act:73192B98-3CD7-4500-A250-DE3F2DF78C5C .

COI-based diagnosis: Five diagnostic (autapomorphic) positions in the alignment: 325(G), 448(C), 514(G), 580(G) and 634(C).

Shell (data for holotype shown within parentheses): Size small for the genus: length 4–6.5 (6.5) mm, width 2.5–4.5 (4.5) mm, height 1.5–2.5 (2.5) mm; thin, ellipsoidal, depressed; white shell surface with a smooth yellowish periostracum; anterior margin very slightly angled; protoconch of 0.8–1 (1) whorl, diameter of nucleus 0.19–0.21 (0.19) mm; teleoconch smooth except for distinct commarginal growth ridges; apertural margin thin, interior glossy white; lamella narrow to wide, width 0.34–0.8 (0.8) mm.

Soft parts (ethanol preserved): Cephalic tentacles completely whitish or grey at the base; pseudoproboscis whitish.

Radula: Taenioglossate, 2-1-R-1-2; marginal teeth sickle shaped; internal marginals with few denticles on the inner edge; lateral teeth triangular, highly denticulated on outer edge, inner edge highly denticulated or presenting a single denticle; rachidian tooth triangular, highly denticulated on both edges.

Host: The holotype was attached to P. caducum (MNHN-IM-2007-39095) ( Fig. 9B ).

Distribution: So far known only from Madagascar and the Mozambique Channel, at depths of 357– 640 m.

Remarks: Hyalorisia kely n. sp. was found off Mahajanga, Madagascar (MIRIKY: Stn CP3268). Here, it occurred sympatrically with H. lehibe n. sp. (MOTU-5) and syntopically with H. madagascarensis n. sp. (MOTU-10).

Figures

Figure 3. Protoconchs of Hyalorisia. A. Hyalorisia galea, MNHN-IM-2013-61536. B. Hyalorisia neocaledonica n. sp., MNHN-IM-2013-65907. C. Hyalorisia tosaensis, MNHN-IM-2007-34794. D. Hyalorisia nupta n. sp., MNHN-IM-2007-34005. E. Hyalorisia lehibe n. sp., MNHN-IM-2007-39212. F. Hyalorisia nanhaiensis n. sp., MNHN-IM-2013-34796. G. Hyalorisia kely n. sp., MNHN-IM-2007-38809. H. Hyalorisia melanesica n. sp., MNHN-IM-2013-58359. I. Hyalorisia profunda n. sp., MNHN-IM-2007-33828. J. Hyalorisia madagascarensis n. sp., MNHN-IM-39292. K. Hyalorisia solomonensis n. sp., MNHN-IM-2007-34215. Scale bars = 100 µm.

Figure 5. Shells of Hyalorisia. A. Hyalorisia lehibe n. sp., holotype, MNHN-IM-2007-39212, off Mahajanga, Madagascar (L = 15 mm). B. Hyalorisia nanhaiensis n. sp., holotype, MNHN-IM-2013-59534, S of Dongsha (=Pratas) Islands, South China Sea (L = 8.5 mm). C. Hyalorisia kely n. sp., holotype, MNHN-IM- 2007-39091, off Mahajanga, Madagascar (L = 6.5). D. Hyalorisia melanesica n. sp., holotype, MNHN-IM-2007-33873, Bellona Reefs, New Caledonia (L = 6.6 mm). Scale bars = 2 mm.

Figure 7. Radulae of Hyalorisia (A–I) and detail of the rachidian tooth (J–R). A, J. Hyalorisia galea MNHN-IM-2013-60195. B, K. Hyalorisia neocaledonica n. sp., MNHN-IM-2013-65647. C, L. Hyalorisia tosaensis, MNHN-IM-2013-58352. D, M. Hyalorisia nupta n. sp., MNHN-IM-2013-68952. E, N. Hyalorisia nanhaiensis n. sp., MNHN-IM-2013-59697. F, O. Hyalorisia kely n. sp., MNHN-IM-2007-38809. G, P. Hyalorisia melanesica n. sp., MNHN-IM-2007-34205. H, Q. Hyalorisia madagascarensis n. sp., MNHN-IM-2007-39090. I, R. Hyalorisia solomonensis n. sp., MNHN-IM-2007-34215. Scale bars = 100 µm.

Figure 9. Bivalve hosts (Propeamussium spp.) with foot mark (black arrows) and notch (white arrows) of Hyalorisia. A. Propeamussium sibogai, MNHN-IM-2007- 33954 (L = 46.7 mm), host of H. nupta n. sp. (MNHN-IM-2007-34010). B. Propeamussium caducum, MNHN-IM-2007-39095 (L = 17.8 mm), host of H. kely n. sp. (MNHN-IM-2007-39091). C, D. Propeamussium dalli, MNHN-IM-2013-60196 (L = 83 mm) with H. galea (MNHN-IM-2013-60195) still attached. Photo credits: MNHN; taken by Yves Terryn (A, B) and Laurent Charles (C). Scale bars = 5 mm.