Laevichlamys squamosa (Gmelin, 1791)

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 : 244-246

Laevichlamys squamosa (Gmelin, 1791)

Figs 69C,E, 70, 71E –H

Ostrea squamosa Gmelin, 1791: 3319 , no. 17.

Ostrea anonyma Gmelin, 1791: 3329 , no. 73.

Pecten squamosus (Gmelin) .–Bosc, 1802: 263; G. B. Sowerby II, 1842: 69, pl. 13, figs 48–50; Reeve, 1853: sp. 65, pl. 18, figs 65a–b.

Pecten hybridus (Gmelin) .– Lamarck, 1819: 177, no. 56 (misidentification).

Pecten serratus G. B. Sowerby II. –Reeve, 1853: sp. 46, pl. 12, figs 46a–b (misidentification as P. serratus G. B. Sowerby II, 1842 ; junior primary homonym of Pecten serratus Nilsson, 1827 ).

Pecten dissimilis Fischer, 1858: 341 (in part) (junior primary homonym of Pecten dissimilis Fleming, 1828 ).

Pecten (Chlamys) squamosa [sic] (Gmelin).–Dautzenberg & Bavay, 1912: 14; Adam & Leloup, 1939: 58; Wilkins, 1953: 14–15, pl. 5, figs 16–18.

Mimachlamys grossiana Iredale, 1939: 352 , pl. 5, figs 23–23a.

Chlamys squamosa (Gmelin) .– Waller, 1972a: 237, fig. 3, pl. 3, figs 38–41; Abbott & Dance, 1982: 312, fig; Dijkstra, (1983–1994) 1984: 16, figs; Wells & Bryce, 1988: 158, pl. 60, fig. 584; Dijkstra et al., 1989: 24; Dijkstra et al., 1990: 4–5, figs; Dharma, 1992: 84, pl. 20, fig. 4; Bernard et al., 1993: 49; Wells, Slack-Smith & Bryce, 2000: 42; Dharma, 2005: 248, pl. 99, figs 3a–c; Xu & Zhang, 2008: 83, fig. 228.

Chlamys (Mimachlamys) squamosa (Gmelin) .– Rombouts, 1991: 30, pl. 12, fig. 2.

Chlamys (Chlamys) squamosa (Gmelin) .–Springsteen & Leobrera, 1986: 329, pl. 93, fig. 16; Dijkstra, 1990a: 11; Lamprell & Whitehead, 1992: [18], pl. 7, fig. 39; Subba Rao & Dey, 2000: 222.

Laevichlamys squamosa (Gmelin) .– Waller, 1993: 203–204; Dijkstra, 1997: 322, figs 13–17; Dijkstra, 1998a: 33, pl. 6, figs 1–4; Slack-Smith & Bryce, 2004: 237; Raines & Poppe, 2006: 208, 211, upper figs; pl. 151, figs 1–3, 5–6; pl. 152, figs 1–7; pl. 296, fig. 2; Dijkstra & Moolenbeek, 2008: 19; Huber, 2010: 208; Raines, 2010: 624, pl. 1003, figs 1–7; Dijkstra, 2013: 69, pl. 19, figs 1a–d, pl. 20, figs 4a–b.

Chlamys (Laevichlamys) squamosa (Gmelin) .–Hayami, 2000: 899, pl. 447, fig. 11.

Comments on synonymy. Gmelin (1791: 3329) referred only to Lister (1687: pl. 184, sp. 21) in the description of Ostrea anonyma . This is the same reference as he cited for O. squamosa . Therefore, these names are objective synonyms. As first revisers, we select the name Ostrea squamosa as the name to be used for the species named both Ostrea squamosa and Ostrea anonyma by Gmelin (1791).

Type data. Ostrea squamosa Gmelin : lectotype (lv) NHMUK (Sloane collection), refigured by Wilkins (1953: pl. 5, figs 16–18), designated by Dijkstra (1991: 32). Type locality: unknown. Designated as Queensland, Australia by Dijkstra (1998a: 33). Gmelin referred only to Lister (1687: pl. 184 fig. 21) for both species, so the same specimen is the lectotype of both Ostrea squamosa and O. anonyma of Gmelin (1791).

Mimachlamys grossiana Iredale : holotype (pr) AM C.019177 (Fig. 71G–H). Type locality: Australia, QLD, Moreton Bay , Stradbroke Island.

Additional material examined. — AUSTRALIA: QUEENSLAND: Torres Strait,off Murray Island, 9°56'S 144°04'E,dead, 9–15 m, 1 v (1 v, C.030272;4 v, C.030273;1 v,C.161012);Reef 13-074, 13°29'S 144°02' E,dead, 7–10 m (1 v,C.338905); Lizard Island, Watsons Bay, 14°40' S 145°27'E, dead, 5 m (1 pr, C.133009); between Palfrey & Lizard Islands , 14°41'S 145°27'E, in lagoon, dead, 1 m (1 pr, C.107857); Lizard Island,Bird Islet, 14°41'S 145°28'E,dead, 0–24 m (3 v,C.338907);Lizard Island, No. 1 Bommie, 14°41'S 145°28' E, lagoon, alive, 0–15 m (1 pr, C.339122);W of Lizard Island,Eyrie Reef, E reef slope, 14°42'S 145°23' E,dead, 3–11 m (1 v,C.338906);Ruby Reef, NW side, 15°44'S 145°47' E, dead, 8–16 m (1 pr, C.157610); Low Isles, 16°23'S 145°34'E, dead, 16–22 m (2 v, C.119530); NE of Townsville, Wheeler Reef, N side, 18°46'S 147°31'E, dead, 11 m (1 pr, C.338909); E of Townsville, Broadhurst Reef, 18°57'S 147°44'E, dead, subtidal (1 pr, C.131213); E of Townsville, Little Broadhurst Reef, 18°59'S 147°43'E, dead, subtidal (1 pr, C.132033); E of Townsville, Broadhurst Reef, 18°57'S 147°44'E,alive,subtidal (1 pr,C.132034;1 pr, C.132035;1 pr, C.132036; 1 pr, C.132037; 2 pr, C.132038; 1 pr, C.132039; 1 pr, C.338912); E of Townsville, Broadhurst Reef, 18°57' S 147°44' E,dead,sublittoral (1 pr,C.132040);E of Townsville, Broadhurst Reef, 18°57'S 147°44'E, alive, 10–15 m (1 pr, C.338911); Swain Reefs, 20 mls N of Heralds Prong No. 1 Reef, 21°10'S 151°24'E, alive (2 pr, C.119531); Swain Reefs, Mystery Reef, 21°22'S 152°01'E, dead, 6–10 m (1 v, C.161839); Swain Reefs, Mystery Reef, 21°23'S 152°02'E, alive, 3–6 m (1 pr, C.339124); Swain Reefs, Reef 21-189, 21°27'S 151°41'E, dead, 9–10 m (1 pr, C.338910); Swain Reefs, Thomas Cay, 21°36' S 152°21' E, dead, intertidal (1 v, C.338908); Moreton Bay, Stradbroke Island, 27°35' S 153°28'E,dead (1 pr,C.019177). WESTERNAUSTRALIA: Abrolhos Islands , Pelsaert Group,Mangrove Islands , 28°52'S 113°58'E,dead (1 pr,C.119529);Montebello Islands , 20°26'S 115°32'E, alive (1 pr, C.049665); Broome, Entrance Point, 18°01'S 122°12'E, alive (1 v, C.119528; 2 pr, C.121356); Beagle Bay, 16°59'S 122°40'E, dead (15 v,C.119494);King Sound, 16°50'S 123°30'E,alive (1 pr,C.097429);Cape Leveque, 16°24'S 122°55' E,dead (1 v,C.160997 [in part]). NORTHERN TERRITORY: Arnhem Land, Gove Peninsula, Yirrkala, 12°15'S 136°53'E, dead (3 v, C.060179); Arnhem Land, Gove Peninsula, Yirrkala, 12°15'S 136°53'E, dead (1 v, C.338904). — KENYA: Mombassa, Old Port, 4°03'S 39°41'E,alive (1 pr,C.339125).— MAURITIUS:off west coast, alive, 27 m (1 pr, ZMA Moll.142947).— THAILAND:off west coast, Kantang, Khor Muk, alive, 25–40 m (9 pr, ZMA Moll.143669). — MALAYSIA: off east coast, alive, 20–30 m (8 pr, ZMA Moll.140361). — PHILIPPINE ISLANDS : Cebu, Mactan Island, off Buyong Beach, 10°05'N 124°0'E, dead, 7–30 m (1 v, C.143059); Bohol, Pamilacan Island, 9°30' N 123°55'E,dead, 1–3 m (2 v,C.161933);Mindanao, Davao Gulf, Talikud Island,alive, 20–28 m (8 pr, ZMA Moll.144473). GUAM:off Orote Cliffs,alive, 20–25 m (1 pr, ZMA Moll.142471).— INDONESIA:Lombok,Gili Trawangan Isle,alive, 3 m (1 pr, ZMA Moll.142952). — PAPUA NEW GUINEA: Madang, Kranket Island, 5°11'S 145°51'E, alive, intertidal (1 pr, C.339123); Port Moresby, Quayles Reef, alive, 20 m (1 pr, ZMA Moll.142954).— SOLOMON ISLANDS :W coast Malaita Island,S of Aoki [Auki],Laulasi Island, Lee Reef, 8°52' S 160°44'E, dead, 6–11 m (1 pr,C.096475). CORAL SEA:Osprey Reef, 13°53'S 146°31' E,dead, 10–17 m (1 pr,C.159356).— NEW CALEDONIA: Poindimié, 20°56' S 165°20'E, dead (12 v, C.103837); Aquarium de Nouméa, 22°19'S 166°27'E,alive (5 pr,C.080825). VANUATU:S coast of Efate Island, Erakor Lagoon, 17°45' S 168°20'E, dead (1 v, C.338914).— FIJI ISLANDS :Viti Levu, Nadi Bay [Tomba Ko Nandi], 17°44'S 177°25'E, dead, 9–35 m (12 v, C.067853); Viti Levu,Nadi Bay [Tomba Ko Nandi], 17°44'S 177°25'E,alive(2 pr,C.338913).— SAMOA ISLANDS :Tutuila, Utelei, alive, 6 m (1 pr, ZMA Moll.142470). TONGA: Tongatapu, Fafa Island, off Nuku’alofa, alive, 2–3 m (3 pr, ZMA Moll.142472).

Description. Shell up to 96 mm high (Huber, 2010), most specimens under 45 mm; thin, flattened, subcircular to oblong, right valve slightly more inflated than left, inequivalve, almost equilateral, auricles highly unequal in size and shape, umbonal angle c. 90°; colour variable, found in almost all colours, with zigzag pattern, paler radial streaks, and/or blotched, a few specimens uniform in colour.

Figure 70. Distribution of Laevichlamys squamosa (Gmelin) (circles) and L. wilhelminae (Bavay) (stars).

Radial sculpture of left valve irregular in prominence and unevenly spaced, with 9–12 low, coarsely scaly radial costae; 1–5 weak squamous secondary riblets intercalated in each radial interspace; some specimens with almost smooth interspaces. Sculpture on right valve of more even prominence, with c. 25–35 closely spaced, narrow, squamous radial riblets. Antimarginal microsculpture in interspaces in early growth stage, shagreen microsculpture lacking. Anterior auricles much larger than posterior ones, bearing c. 6 scaly radial riblets, almost smooth on left valve, more prominent on right valve. Posterior auricles smooth or weakly sculptured with a few commarginal lamellae. Byssal notch relatively deep, byssal fasciole broad. Functional ctenolium well-developed, with 5–8 teeth.

Dimensions. Illustrated specimen: QLD, GBR, Broadhurst Reef, E of Townsville, sublittoral ( AM C.132040): rv: H 46.6, L 43.8 mm; lv: H 45.6, L 42.0 mm; D 10.8 mm. Iredale (1939: 352) stated the dimensions of the holotype of Mimachlamys grossiana as H 44, L 40 mm .

Habitat. Living in the littoral to upper bathyal zones, byssally attached to undersides of rock or coral boulders or amongst coral rubble on soft sediment (muddy sand or sand).

Distribution. Tropical Indo-West Pacific, from southern Japan to northernAustralia, westwards into the Indian Ocean to Kenya and Mauritius (not recorded from the Arabian Sea), eastwards into the central Pacific to Tonga (not known from the Hawaiian Islands or French Polynesia) (Waller, 1972: 239; Raines & Poppe, 2006: 210); Japan to Mascarenes, 5–55 m (Huber, 2010: 208); Philippines, 4–38 m ( Raines, 2010: 624; Dijkstra, 2013: 72); Indonesia, 0–16 m (Dijkstra, 1991: 32); Papua New Guinea, 3–30 m (Dijkstra, 1998a: 33–34); Vanuatu, 0–60 m (Dijkstra & Maestrati, 2012: 399). Maximum depth range of live-taken specimens is from the intertidal zone to 60 m. Present specimens from Australia alive from the intertidal zone to 15 m.

Remarks. The present specimens from Australia are identical to the type material of Laevichlamys squamosa . This species has often been attributed incorrectly to different nominal taxa in the past (see Iredale, 1939: 353) from

Figure 71. A, C, Laevichlamys wilhelminae (Bavay) , pair, AM C.157604, Ham Cay, GBR, QLD; rv exterior (A), lv exterior (C). B, D, Laevichlamys mollita (Reeve) , specimen in Fig. 69D, I; lv exterior (B), rv exterior (D). E–H, Laevichlamys squamosa (Gmelin) ; (E, F) specimen in Fig. 69C, E; lv exterior (E), rv exterior (F); (G, H) pair, holotype of Mimachlamys grossiana Iredale, AM C. 019177, Stradbroke Island, Moreton Bay, QLD; lv exterior (G), rv exterior (H). Scale bars represent 10 mm.

outside Australia. Therefore, Iredale (1939: 352) considered the Queensland specimens to be distinct. However, the lectotype of Laevichlamys squamosa , Sloane’s specimen (lv) illustrated in Lister (1687), preserved in NHMUK, is morphologically indistinguishable from Iredale’s material of Mimachlamys grossiana .