New species and new records of littoral and bathyal living Pectinoidea (Bivalvia: Propeamussiidae, Cyclochlamydidae, Pectinidae) from the western and southwestern Pacific Author Dijkstra, Henk H. Naturalis Biodiversity Center, P. O. Box 9517, NL- 2300 RA Leiden (The Netherlands) henk. dijkstra @ naturalis. nl dijkstra@naturalis.nl Author Maestrati, Philippe ISYEB, UMR 7205 CNRS, MNHN, UPMC, EPHE, Muséum national d’Histoire naturelle, Sorbonne Universités, case postale 51, 57 rue Cuvier, F- 75231 Paris cedex 05 (France) philippe. maestrati @ mnhn. fr Published on 29 December 2017 maestrati@mnhn.fr text Zoosystema 2017 2017-12-31 39 4 473 485 http://dx.doi.org/10.5252/z2017n4a3 journal article 10.5252/z2017n4a3 1638-9387 4578634 urn:lsid:zoobank.org:pub:CE174614-6609-404A-9909-673B309820D5 Cyclochlamys corrugata n. sp. ( Fig. 3 A-H) TYPE MATERIAL. — Papua New Guinea . KAVIENG 2014, stn KB20, 02°45.2’S , 150°41.7’E , – 8 m , alive, 5 paratype spms ( MNHN- IM-2013-50881, 50883, 50885, 50887, 50889). — Stn KS35, 02°38.8’S , 150°40.7’E , 4-5 m , alive, 3 paratype spms ( MNHN- IM-2013-53544, 53545, 53547). — Stn KB66, 02°35.2’S , 150°50.3’E , – 17 m , alive, holotype spm (MNHN-IM-2013-55062). — Same stn, alive, 2 paratype spms (MNHN-IM-2013-55060, 55061). OTHER MATERIAL. — Papua New Guinea . KAVIENG 2014, Stn KB08, 02°33.2’S , 150°48.2’E , – 13 m , 1 lv . — Stn KB10, 02°33.5’S , 150°47.4’E , – 13 m , alive, 2 spms (1 MNHN , 1 NBC ). — Stn KB20, 02°45.2’S , 150°41.7’E , – 8 m , alive, 1 spm, 4 lv . — Stn KB34, 02°43.7’S , 150°37.1’E , – 43 m , 1 lv . — Stn KS35, 02°38.8’S , 150°40.7’E , 4-5 m , alive, 1 spm. — Stn KS61, 02°35.2’S , 150°43.1’E , 9-13 m , 3 lv . — Stn KS63, 02°45.2’S , 150°41.7’E , 10-12 m , alive, 2 spms, 4 lv . — Stn KB68, 02°45.2’S , 150°41.7’E , 22-27 m , 1 lv , 1 rv. — Stn KB74, 02°45.2’S , 150°44.5’E , – 20 m , alive, 1 spm. — PAPUA NIUGINI 2012, stn PB16, 05°04.7’S , 145°48.8’E , – 5 m , alive, 4 spms (3 MNHN , 1 NBC ). — Stn PB40, 05°15.9’S , 145°47.1’E , 9-11 m , alive, 1 spm, 1 lv . — Stn PS41, 05°15.9’S , 145°47.1’E , – 10 m , 3 lv . — PD51, 05°10.1’S , 145°50.3’E , 3-12 m , 1 lv . — Stn PD63, 05°09.9’S , 145°48.3’E , 0-15 m , 1 lv . ( MNHN ). TYPE LOCALITY. — Papua New Guinea , New Ireland , mainland, N-coast, 02°35.2’S , 150°50.3’E , – 17 m , alive in sand and rubble, 24.VI.2014 (KAVIENG 2014, stn KB66). ETYMOLOGY. — Left valve commarginally wrinkled and ruffled (Latin corrugata , adjective meaning wrinkled or ruffled). DISTRIBUTION. — Papua New Guinea , live in 4-20 m (maximum depth range), 5-20 m (minimum depth range). DESCRIPTION Shell Up to 2.8 mm high, fragile, strongly posteriorly oblique, inequivalve, inequilaterial, wider than high, lv opaque whitish, rv translucent. Shape irregular, variable, typically changing during ontogeny, commonly associated with change in spacing of commarginal lamellae (habitat constriction). Prodissoconch 220 µm long, lv larval shell conical and granular, rv larval shell almost flat with irregularly spaced ridges and weak radial grooves. Left valve Disc with 3-6 weak radial plicae, lacking in some specimens, in early ontogeny smooth ( c. 0.3-0.5 mm high), after that very closely spaced commarginal lamellae commence and develop to the periphery; on lamellae, very closely set small nodules present at intersections, resembling pearl strands; auricles similarly sculptured and continuous with disc, posterior auricle distinctly larger than anterior; interlamellar spaces narrow, with very closely spaced radial threads with convex crests, lacking in some specimens; ventral margin weakly angular to slightly convex. Right valve Disc and all but dorsal border of posterior auricle with outer layer of commarginal hexagonal prisms, more elongate in late ontogeny. Posterior auricle continuous with disc, smooth; anterior auricle distinctly demarcated from disc with 3-4 nodulous radial threads. Byssal notch of moderate depth, byssal fasciole rather broad. Dimension of holotype H 2.8 mm , W 3.4 mm , D 0.9 mm . REMARKS The present species resembles three congeneric species, viz. Cyclochlamys nepeanensis (Pritchard & Gatliff, 1904) , known from southeastern and southern Australia , Cyclochlamys incubata ( Hayami & Kase, 1993 ) from Japan , and Cyclochlamys irregularis Dijkstra & Marshall, 2008 from New Zealand . All of these species have nodules on the intersections of the commarginal lamellae and radial riblets of the left valve, although much more widely spaced than on the left valve of the present species ( C. corrugata n. sp. combined together, C. nepeanensis , C. incubata , and C. irregularis with strongly variable interspaces, 6-10 per mm on central part of disc). Moreover, the shape of C. corrugata n. sp. is strongly posteriorly oblique and in most specimens with a more or less angular ventral margin, with angulations caused by the radial plicae ( C. nepeanensis is circular, C. incubata weakly posteriorly oblique, and C. irregularis circular to slightly posteriorly oblique; all lack radial plicae). Smooth specimens from stn KB50 (lv) and KS61 ( 2 lv ) are close to or a smooth variant of C. corrugata n. sp. , viz. the faint granular sculpture on the anterior auricle of the left valve of stn KB50 is very similar to that of C. corrugata n. sp.