Laevichlamys deliciosa ( Iredale, 1939 )

Dijkstra, Henk H. & Beu, Alan G., 2018, Living Scallops of Australia and Adjacent Waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae), Records of the Australian Museum (Rec. Aust. Mus.) 70 (2), pp. 113-330 : 241-243

Laevichlamys deliciosa ( Iredale, 1939)

Figs 66, 67G–J, 69A–B

Mimachlamys deliciosa Iredale, 1939: 350 , pl. 5, figs 22–22a; Dijkstra, (1983–1994) 1990: 5, figs.

Chlamys (Chlamys) princessae Kuroda & Habe in Kuroda et al., 1971: 364, pl. 79, figs 16–17; Rombouts, 1991: 17, pl. 24, fig. 6; Higo et al., 2001: 156, fig. B445 (paratype, not holotype as indicated).

Chlamys (Chlamys) deliciosa (Iredale) .–Dijkstra, 1990a: 8; Lamprell & Whitehead, 1992: [20], 172, pl. 8, fig. 43.

Chlamys deliciosa (Iredale) .–Dijkstra, 1991: 30; Dharma, 2005: 248, pl. 99, figs 9a–b.

Chlamys (Mimachlamys) deliciosa (Iredale) .– Rombouts, 1991: 28.

Laevichlamys deliciosa (Iredale) .–Dijkstra & Kastoro, 1997: 268, fig. 134; Dijkstra & Kilburn, 2001: 288, figs 23–24; Raines & Poppe, 2006: 200, 201, upper figs; pl. 142, figs 2–3; Dijkstra & Maestrati, 2008: 105, figs 44–45; Huber, 2010: 207; Raines, 2010: 622, pl. 1002, fig. 2; Dijkstra, 2013: 65, pl. 17, figs 2a–d, pl. 28, figs 4a–b.

Type data. Mimachlamys deliciosa , lectotype (pr) AM C.089669 (Fig. 67G–H), herein designated, 4 paralectotypes (pr) AM C.212823. Type locality: Australia, N QLD, GBR Expedition stn 14, 0.5 mile south-east of Lizard Island, Low Isles, 14°41'S 145°29'E, 35 m.

Figure 69. A, B, Laevichlamys deliciosa (Iredale) , lectotype, specimen in Fig. 67I, J; lv exterior (A), rv interior (B).C, E, Laevichlamys squamosa (Gmelin) , pair, AM C.132040, sublittoral, Broadhurst Reef, E of Townsville, GBR, QLD; lv exterior (C), rv interior (E). D, I, Laevichlamys mollita (Reeve) , pair, AM C.132030, sublittoral, Broadhurst Reef, E of Townsville, GBR, QLD; rv interior (D), lv exterior (I). F, H, Laevichlamys cuneata (Reeve) , specimen in Fig. 67D, F; lv exterior (F), rv interior (H). G, J, Laevichlamys limatula (Reeve) , specimen in Fig. 67E, K, L; rv interior (G), lv exterior (J). K, L, Laevichlamys andamanica (Preston) , specimen in Fig. 67B; lv exterior (K) and interior (L). Scale bars represent 10 mm.

Chlamys (Chlamys) princessae Kuroda & Habe : holotype (pr) NSMT-Mo R18503, figured by Higo et al. (2001: 156, fig. B445), refigured by Showa Memorial Institute (ed.) (2002: 60). Type locality: Japan, Sagami Bay.

Additional material examined. —AUSTRALIA: QUEENSLAND: 0.25 ml N of North Direction Isle, 14°44'S 145°31'E, alive, 34.5 m (3 pr, C.119510); Swain Reefs, 3 km NE of W side of Gillett Cay , 21°42'S 152°26'E, dead, 64–73 m (1 v, C.336902). WESTERN AUSTRALIA: W of Dongara , 29°20.8' S 114°05.7' E, dead, 192–219 m (2 fragm., WAM497 ); off Rowley Shoals , 33 n. miles S of Bedwell

Island, Clerke Reef, 17°48.7'– 17°48.2'S 119°22.3'– 119°23.1'E, dead, 250 m (1 v, WAM 12560).— JAPAN: Okinawa, 1 km WNW of Onna, 26°29.8'N 127°50.7'E, dead, 45 m (1 v,C.336903); Okinawa,Seragaki,alive, 38–40 m (3 pr, ZMA Moll.141409).— PHILIPPINE ISLANDS : Cebu,off Sogod,alive, 160–200 m (1 pr, ZMA Moll.142198); Bohol,Balicasag Island,alive, 130–140 m (1 pr, ZMA Moll.139557).— INDONESIA: Tanimbar Islands , 7°59'S 133°02'E, alive, 184–186 m (1 pr, ZMA Moll.139810); NNE coast of Sumba, E of Melolo, 9°53.2'S 120°43.2'E, alive, 100 m (1 pr, ZMA Moll.144668). CORAL SEA: Chesterfield Islands , 19°49'S 158°21' E, alive, 42 m (1 pr, ZMA Moll.142204). — NEW CALEDONIA: Grand Récif Sud, 22°46' S 167°01'E, alive, 65 m (1 pr, ZMA Moll.142199). — FIJI ISLANDS : Viti Levu, Yanuca Island, dead, 34 m (1 v, ZMA Moll.143983).

Description. Shell up to 25 mm high, most specimens under 20 mm; a few specimens subcircular, most oblong, somewhat prosocline, right valve slightly more inflated than left, almost equivalve and equilateral, auricles very unequal in shape and size, umbonal angle c. 80–85°; uniform cream, orange (most specimens), yellow, pink or purple, some specimens patterned with darker rays or blotches.

Both valves sculptured with numerous fine, unevenly spaced, spinous radial riblets, increasing to c. 45–50 by intercalation towards ventral margin in adult stage. Radial interspaces bearing granulate or reticulate microsculpture in early radial stage, smooth in late radial stage near ventral margin. Anterior auricles long, bearing 9–14 delicate radial riblets, posterior auricles very short with fewer (6–10) still more delicate riblets.Anterior auricle of left valve somewhat declined near disc flank. Postero-dorsal margin somewhat declivous. Byssal notch very weak, byssal fasciole narrow. Functional ctenolium well-developed, with c. 4–6 teeth.

Dimensions. Illustrated specimen: QLD, GBR, 0.25 miles N of North Direction Isle, 34.5 m ( AM C.119510); rv: H 13.5, L 10.7 mm; L 11.7 m (including anteriorly protruding auricle); lv: H 13.5, L 10.7, D 4.7 mm. Iredale (1939: 351) stated the dimensions of a representative syntype (presumably the lectotype) as H 17, L 14 mm .

Habitat. Living in the littoral zone to the upper bathyal zone, amongst coral rubble on sandy or muddy sand bottoms. Surface of many specimens encrusted with sponges.

Distribution. Subtropical-tropical Indo-West Pacific, from southern Japan to northern Australia, westward into the Indian Ocean to Mozambique and South Africa (not recorded from the Red Sea, Arabian Sea and Persian Gulf), and eastwards across the Pacific to the Fiji Islands (Raines & Poppe, 2006: 200); Africa to Japan, 35–390 m (Huber, 2010: 207); Mozambique, 80 m, South Africa, 10–100 m (Dijkstra & Kilburn, 2001: 289); Philippines, c. 80 m (Dijkstra, 2013: 66); Indonesia, 80–212 m (Dijkstra, 1991: 30; Dijkstra & Kastoro, 1997: 268); Solomon Islands , 120–655 m, dead; Norfolk Ridge, 180–250 m, dead (Dijkstra & Maestrati, 2008: 106); Vanuatu, 45–101 m (Dijkstra & Maestrati, 2012: 399). Maximum depth range of live-taken specimens 10– 390 m. Present specimens from Australia alive at 34.5 m.

Remarks. The present specimens from western and eastern Australia are indistinguishable from the type of Laevichlamys deliciosa . Typical specimens are strongly oblong, but the shape (subcircular to elongate) and convexity (strongly inflated to more flattened) of this species are rather variable.