Semipallium flavicans ( Linnaeus, 1758 )

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 : 264-265

Semipallium flavicans ( Linnaeus, 1758)

Figs 80F–G, 81, 82A–B

Ostrea flavicans Linnaeus, 1758: 698 , no. 173; Dijkstra, 1999: 425, figs 9C–D (lectotype).

Pecten tigris Lamarck, 1819: 171 , no. 30; Defrance, 1825: 243; G. B. Sowerby II, 1842: 68, pl. 14, figs 95–96; Philippi, 1845: 101, pl. 1, figs 6a–c; Reeve, 1853: sp. 77, pl. 20, fig. 77; Küster & Kobelt, 1888: 129, pl. 35, fig. 10; Dijkstra, 1994: 482, pl. 17, figs 70–74; Dijkstra, 1994: 482, pl. 17, figs 70–73 (lectotype).

Pecten (Pallium) tigris Lamarck. –Adam & Leloup, 1939: 60.

Complicachlamys tigris (Lamarck) .–Habe, 1964b: 174, pl. 53, fig. 14.

Semipallium (Semipallium) tigris (Lamarck) .–Hertlein, 1969: N365, figs C.87.3a–b; Wang, 1985: 502, fig. 1.

Semipallium tigris (Lamarck) .–Abbott & Dance, 1982: 308, fig; Wells & Slack-Smith, 1986: 54; Dijkstra, 1991: 40; Rombouts, 1991: 59, pl. 22, figs 1–1a; Dharma, 1992: 84, pl. 20, figs 13–13a; Lamprell & Whitehead, 1992: [28], pl. 12, fig. 69; Bernard et al., 1993: 49; Dijkstra, 1997: 334, figs 46–49; Dijkstra, 1998a: 38, pl. 7, figs 6–9; Dijkstra, Drivas & Jay, 1998: 9, fig. 15; Hayami, 2000: 901, pl. 448, fig. 20; Dharma, 2005: 250, pl. 100, figs 10a–c; Xu & Zhang, 2008: 87, fig. 246; Dijkstra, 2013: 84, pl. 22, figs 1a–d, pl. 30, figs 4a–b.

Semipallium flavicans (Linnaeus) .–Dijkstra, 1999:426; Raines & Poppe, 2006: 240–241, lower figs; pl. 192, figs 1–5; Huber, 2010: 206; Raines, 2010: 636, pl. 1009, figs 4–7.

Type data. Ostrea flavicans Linnaeus : lectotype (pr) UUZM [not registered], designated by Dijkstra (1999: 426, figs 9C–D), 2 possible paralectotypes (lv + rv) UUZM [not registered]. Type locality: “O. australiore” [Indo-West Pacific].

Pecten tigris Lamarck : lectotype (pr) MNHN Moll21194, designated by Dijkstra (1994: 483, figs 70–73), paralectotype (pr) MNHN Moll 21195. Type locality: “l’Océan indien” [Indian Ocean].

Additional material examined. — AUSTRALIA: QUEENSLAND: GBR, Marion Reef, 19°17'S 152°13' E , dead, 10 m (1 pr, NTM P012670 ). WESTERN AUSTRALIA: S Muiron Island , 21°39.86'S 114°20.06' E , dead, 13–15 m (1 v, WAM); Rowley Shoals , approx. 17°10'S 119°20' E , dead (1 v, WAM); Rowley Shoals, Clerke Reef, 17°10'S 119°20' E , dead, 9–18 m (1 v, WAM 1617.81 ; 1 v, WAM 1545.81 ); Macleay Island , 15°56.02'S 123°62.03'E, dead (2 v, WAM); Churchill Reef, 15°31'S 123°17'E , dead (1 v, WAM); Kimberley, NW of Buffon Island , 14°55'S 124°41'E , dead (1 v, WAM); E Montelivet, 14°16.31'S 125°17.59'E , dead (1 pr, WAM); Kimberley, Long Reef,S side, 14°01' S 125°44' E , dead (1 pr + 1 v, WAM522 ); Scott Reef , approx. 14°0' S 121°45'E , dead (1 v, WAM); Cassini Island , 13°56'S 125°38'E , dead (1 pr + 3 v, WAM); Cassini Island , 13°56'S 125°38'E , dead, 20 m (5 v, WAM); Seringapatam , 13°40'S 122°05'E , dead (1 v, WAM); Seringapatam, 13°40'S 122°05'E , dead, 15–17 m (3 v, WAM); Cassini Island , 13°56'S 125°38'E , W side, dead, 20 m (1 v, WAM; 3 v, WAM); Cartier Island , 12°31'S 123°29'E , dead, 10–20 m (1 v, WAM); Hibernia Reef , in lagoon, 11°58'S 123°19'E , dead, 5 m (1 v, WAM); Hibernia Reef , 11°58'S

Figure 81. Distribution of Semipallium flavicans (Linnaeus) (circles), S. fulvicostatum (A.Adams & Reeve) (stars) and S. hallae (Cotton) (triangle).

123°19'E, dead (1 v, WAM). — MOZAMBIQUE: Nacale, alive, 10–12 m (3 pr, ZMA Moll.146134).— MAURITIUS:off west coast,alive, 18–25 m (3 pr, ZMA Moll.143017). — THAILAND:Andaman Sea, Phuket Island, Kaea Noi Island,alive, 20 m (1 pr, ZMA Moll.143678).— PHILIPPINE ISLANDS : Sulu Sea, off Zamboanga,alive, 4–10 m (2 pr, ZMA Moll.140478).— INDONESIA:off NW coast of Sumatra, alive, 2–3 m (5 pr, ZMA Moll.143738).— PAPUA NEW GUINEA: Madang Harbour, Tab Island, S side, 5°11'S 145°50'E, alive, 11 m (1 pr, C.375063); off Madang, N end of Kranket Island, 5°11'S 145°51'E, alive, intertidal (1 pr, C.375062). CORAL SEA: North East Herald Cay, 16°56'S 149°11'E, dead, beach (1 fragm., C.331993). — SOLOMON ISLANDS : Russell Group, Pavuvu Island, Samata, alive, 6–12 m (3 pr, ZMA Moll.143012). — SAMOA ISLANDS :Tutuila Island, Fagasa Bay, alive, 9 m (1 pr, ZMA Moll.143011).

Description. Shell up to 76 mm high (Huber, 2010), rather inflated, right valve more convex than left, subtriangularly ovate, prosocline, inequivalve, inequilateral, auricles very unequal in size, umbonal angle c. 80°; cream with dark brown or reddish brown maculations or bands, yellowish near umbo; right valve paler, interior yellowish, dark brown near resilial pit; red spot on anterior auricle.

Both valves with 8–10 prominent, evenly spaced radial plicae; scaly secondary radial riblets on and between primary plicae; covered with shagreen microsculpture; microsculpture of commarginal lamellae in early growth stage. Dorsal margin straight, somewhat declined on posterior side of auricle. Byssal notch deep, ctenolium welldeveloped. Internal plicae with edges carinate around ventral margin. Hinge with weak resilial and dorsal teeth.

Dimensions. Illustrated specimen: QLD, GBR, Broadhurst Reef, E of Townsville, subtidal (AM C.131558): rv: H 38.2, L 35.5 mm; lv: H 38.5, L 34.9 mm; D 9.7 mm.

Habitat. Living in the littoral to sublittoral zones, byssally attached to undersides of coral slabs or boulders or amongst coral rubble on clean sandy bottoms.

Distribution. Tropical Indo-West Pacific, from southern Japan southwards to northern Australia and westwards into the Indian Ocean to Mozambique and South Africa (not recorded from the northwestern Indian Ocean), and eastwards into the central Pacific to Samoa (Raines & Poppe, 2006: 240); East Africa to Japan, 3–40 m (Huber, 2010: 206); Mozambique, 10–12 m alive, South Africa, 78 m, dead (Dijkstra & Kilburn, 2001: 298); Philippines, 2–52 m ( Raines, 2010: 636; Dijkstra, 2013: 84); Indonesia (as Semipallium tigris ; Dijkstra, 1991: 40); Papua New Guinea, 3–30 m (as Semipallium tigris ; Dijkstra, 1998a: 38–39); Vanuatu, 21 m (Dijkstra & Maestrati, 2012: 400). Maximum depth range of live-taken specimens is from the intertidal zone to 52 m. Present specimens from Australia dead at 5– 20 m.

Remarks. The present specimens from offshore reefs of Australia are indistinguishable from the type material of Semipallium flavicans .