Parvamussium lozoueti, Dijkstra & Maestrati, 2008

Dijkstra, Henk H. & Maestrati, Philippe, 2008, New species and new records of deep-water Pectinoidea (Bivalvia: Propeamussiidae, Entoliidae and Pectinidae) from the South Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 77-114 : 87-89

publication ID	978-2-85653-614-8
DOI	https://doi.org/10.5281/zenodo.5491162
persistent identifier	https://treatment.plazi.org/id/A73487B5-2014-E34F-FF3B-BAE6FEDEFCE5
treatment provided by	Felipe
scientific name	Parvamussium lozoueti
status	sp. nov.

Treatment

Parvamussium lozoueti View in CoL n. sp.

Figs 11-17

TYPE MATERIAL. — Holotype (spm) MNHN 20449 About MNHN and 19 paratypes MNHN 20450-20454 About MNHN , 3 About MNHN HD.

TYPE LOCALITY. — Fiji, 16˚31.05’S, 179˚00.29’W, 670-682 m [BORDAU 1: stn CP 1415] .

MATERIAL EXAMINED. — Fiji. MUSORSTOM 10: stn DW 178˚30’W, 700-707 m, 6 spms, 2 lv, 3 rv (9 paratypes MNHN 1314 About MNHN , 17 About MNHN ˚16’S, 178˚15’E, 656-660 m, 1 spm (paratype MNHN 20452 About MNHN , Figs 14-17; 2 HD); stn CP 1491, 18˚50’S, 178˚27’W, 777- 20451) . — BORDAU 1: stn CP 1415, 16˚315’S, 179˚00’W, 670- 787 m, 1 spm (paratype MNHN 20453 About MNHN ) .

682 m, 4 spms, 2 lv, 2 rv (holotype MNHN 20449 and 7 paraty- Tonga. BORDAU 2: stn DW 1588, 18˚40’S, 173˚52’W, 630-710 pes MNHN 20450, Figs 13, 14; 1 HD); stn DW 1485, 19˚03’S, m, 1 lv (paratype MNHN 20454).

DISTRIBUTION. — Fiji and Tonga; live in 660-777 m.

DESCRIPTION. — Shell up to 17 mm in height, fragile, semi-transparent, inequivalve, inequilateral, subcircular, posteriorly slightly oblique, right valve more convex than left, auricles nearly equal in size, umbonal angle 120˚, colour whitish.

Left valve sculptured with irregularly spaced, numerous radial rows of curved commarginal vesicular lamellae (imbricated radial ribs), commencing unequally 2-3 mm below umbonal margin, increasing with interstitial secondary ones and extending to ventral margin. Preradial stage smooth and glossy. Auricles with commarginal lamellae, anterior more prominent than posterior.

Right valve with closely spaced, commarginal lirae (7-8 per mm in central part of disc). Anterior auricle with commarginal lamellae, transforming into spines on dorsal margin, posterior auricle with closer spaced commarginal lamellae. Byssal notch small.

Delicate internal ribs 12-13 with one or two interstitial rudimentary riblets, commencing 4-5 mm below umbonal margin and extending to ventral apron, with one or two auricular riblets.

Dimensions of holotype: H 17.0, L 17.9, D 3.8.

REMARKS. — The present species somewhat resembles Parvamussium retiolum Dijkstra, 1995 in shape ( P. lozoueti is more circular), but differs completely in sculpture. On the left valve P. lozoueti has a prominent radial vesicular or pustulose sculpture, and P. retiolum a delicate reticular sculpture. This sculpture of P. lozoueti is not seen in other species of Parvamussium . It is known in Cyclopecten , viz. Cyclopecten hoskynsi (Forbes, 1844) from the northern Atlantic, Cyclopecten antiquatus (Philippi, 1844) from the tropical eastern Atlantic, Cyclopecten carlottensis Bernard, 1968 from the northeastern Pacific, and Cyclopecten nakaii Okutani, 1962 from Japan.

Parvamussium texturatum (Dautzenberg & Bavay, 1912) View in CoL , Parvamussium araneum Dijkstra, 1991 View in CoL and Parvamussium vesiculatum Dijkstra, 1995 View in CoL have sculpture of hollow scales or vesicles at the intersections of the radial and commarginal sculpture of the left valve. All these species have commarginal sculpture, which is lacking in P. lozoueti View in CoL .

ETYMOLOGY. — Named after Dr Pierre Lozouet, currently collection manager of Marine Invertebrates at MNHN, and a participant in several of the deep-sea cruises on Norfolk Ridge that collected material reported in the present paper.