Hyalorisia solomonensis 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 : 417-419

Hyalorisia solomonensis Fassio, Bouchet & Oliverio new species

MOTU-9 ( Figs 3K , 6C , 7I, R )

Type material: Holotype: off Santa Isabel , Solomon Islands, SALOMON 2, Stn CP2186 , 08°17 S, 160°00 E, 487–541 m, MNHN-IM-2007-34203 ( male ).

Material examined: Holotype and other material (MNHN-IM-2007-34215, MNHN-IM-2007-34216, MNHN-IM-2007-34217 and MNHN-IM-2013-66982).

Etymology: From the general area of the type locality, Solomon Islands.

ZooBank registration: urn:lsid:zoobank.org:act:65270D2E-622E-461A-BF55-C01018FA7F6E .

COI-based diagnosis: Six diagnostic (autapomorphic) positions in the alignment: 347(C), 373(G), 535(G), 542(C), 544(G) and 553(T).

Shell (data for holotype shown within parentheses): Size small to medium for genus: length 4.5–9 (8) mm, width 3–6 (5) mm, height 1–2 (2) mm; ellipsoidal or ovoidal, depressed; white shell surface with smooth yellowish periostracum; anterior margin rounded; protoconch of 1–1.2 (1.1) whorls, diameter of nucleus 0.08–0.1 (0.08) mm; teleoconch smooth except for distinct commarginal growth ridges; apertural margin thin, interior glossy white; lamella narrow to wide, width 0.23–0.69 (0.69) mm.

Soft parts (ethanol preserved): Head completely whitish or grey at the base; cephalic tentacles whitish with grey base; pseudoproboscis whitish, mantle grey with whitish border.

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 denticulation variable; rachidian tooth triangular, highly denticulated on both edges.

Host: No records available of direct collection from host. Two specimens of P. caducum (MNHN-IM-2007-33865 and MNHN-IM-2007-33866) were found at the same stations and showed marks on the shells corresponding to the contour of the Hyalorisia specimens (MNHN-IM-2007-34216 and MNHN-IM-2007-34217). The holotype was found at a station where the only propeamussiids found were P. caducum and P. investigatoris . Another specimen (MNHN-IM-2007-34215) was found at a station where the only propeamussiid found was P. caducum .

Distribution: So far known only from the Solomon Islands and Papua New Guinea, at depths of 510– 520 m.

Remarks: Hyalorisia solomonensis n. sp. was found sympatrically with H. melanesica n. sp. (MOTU-8) in Ainto Bay, New Britain, Papua New Guinea (Solomon Sea).

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 6. Shells of Hyalorisia (A–C) and detail of the lamella (D, E). A. Hyalorisia profunda, holotype, MNHN-IM-2013-59695, South China Sea (L = 7 mm). B. Hyalorisia madagascarensis n. sp., holotype, MNHN-IM-2007-39090, off Mahajanga, Madagascar (L = 6.5 mm). C. Hyalorisia solomonensis n. sp., holotype, MNHN-IM-2007-34203, SE of Santa Isabel, Solomon Islands (L = 8 mm). D. Wide lamella of Hyalorisia neocaledonica n. sp., MNHN-IM-2013-65645, Lord Howe Rise, New Caledonia. E. Narrow lamella of Hyalorisia tosaensis, MNHN-IM-2013-58352, New Ireland, Papua New Guinea. 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.