Living Scallops of Australia and Adjacent Waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae) Author Dijkstra, Henk H. Author Beu, Alan G. text Records of the Australian Museum 2018 Rec. Aust. Mus. 2018-05-23 70 2 113 330 http://dx.doi.org/10.3853/j.2201-4349.70.2018.1670 journal article 10.3853/j.2201-4349.70.2018.1670 2201-4349 5299017 8084C Pseudamussium challengeri (E. A. Smith , 1891 ) Figs 26, 29A–B, 31A–B Pecten challengeri Smith , 1891: 443 , pl. 35, fig. 25. Chlamys (Veprichlamys) challengeri ( Smith ) .– Iredale, 1929: 164 ; Rombouts, 1991: 34 . Chlamys (Chlamys) challengeri ( Smith ) .–Lamprell & Whitehead, 1992: [20], pl. 8, fig. 46. Veprichlamys challengeri ( Smith ) .–Raines & Poppe, 2006: 248, 249, upper figs; pl. 197, fig. 4. Pseudamussium challengeri ( Smith ) .–Dijkstra & Marshall, 2008: 70, figs 59A–F, 60; Spencer et al ., 2009: 198 . Type data . Lectotype (pr: H 19.0 mm, W 18.4 mm , D 4.6 mm ) NHMUK 1889.2.13.1, herein designated; paralectotype (rv) NHMUK 1889.2.13.2. Type locality: off Sydney, 34°13'S 151°38'E , alive, 410 fathoms [ 750 m ] ( Challenger stn 164b). Additional material examined . — AUSTRALIA : NEW SOUTH WALES : E of Cape Three Points , 33°28'– 33°29'S 152°04'– 152°03'E , dead, 457–476 m (1 v, C.155816) ; off Broken Bay , 33°32'– 33°34' S 152°06'– 152°05' E , dead, 823 m (1 v, C.123385) ; E of Broken Bay , 33°32'– 33°38' S 152°0'– 152°04'E , dead, 823 m (1 v, C.310689) ; off Broken Bay , 33°35'– 33°33'S 152°0'– 152°02'E , alive, 823 m (1 pr, C.343929) ; off Sydney , 33°42' – 33°39'S 151°52'– 151°54'E , dead, 457 m (2 v, C.155830) ; off Sydney , 34°05'S 151°43'E , dead, 750 m (1 v, C.339158) ; SE of Botany Bay , 34°21'– 34°16'S 151°24'– 151°28'E ,dead, 421 m (2 v,C.102825) ; off Port Kembla , 34°39'– 34°35'S 151°15'– 151°17'E , dead, 466 m (1 v, C.140411; 1 v, C.140414) ; off Port Kembla , 34°42'– 34°38'S 151°14'– 151°18'E , alive, 498–521 m (1 pr, C.135831) ; off Nowra , 34°50'S 151°13'E , dead, 550 m (1 v, C.155801) ; off Shoalhaven Bight , 34°54'– 34°50'S 151°14'– 151°15'E , alive, 988–1006 m (1 pr, C.155803) ; E of Brush Island ,35°28'– 35°33'S 150°50'– 150°47'E ,alive, 604 m (1 pr,C.155798) ; E of Ulladulla , 35°31'– 35°36'S 150°47'– 150°44'E , dead, 549 m (1 v, C.310687) ; off Brush Island , Batemans Bay , 35°36'– 35°44'S 150°44' – 150°38'E , dead, 549–586 m (1 v, C.310688) ; E of Brush Island , 35°44'– 35°40'S 150°38'– 150°41'E , dead, 549 m (1 pr, C.105420) ; E of Eden , 36°56'– 36°58' S 150°20'E , dead, 274 m (2 v, C.155797) ; E of Eden , 36°59'– 36°58'S 150°21' – 150°22.7'E , dead, 716–900 m (1 v, C.310686) . VICTORIA : SE of Gabo Island , 37°48'– 37°37'S 150°13' – 150°16'E , dead, 494 m (1 pr, C.134357) . SOUTHAUSTRALIA : off Cape Martin , 38°07'S 140°0'E ,dead, 667 m (1 v,C.339157) . WESTERN AUSTRALIA : Albany ,off Bald Island , 400–420 m , dead,trawled on sand and mud (2 v, HM );off Albany ,35°23'33"– 35°24' 04"S 118°18'32"– 118°18'22"E ,dead, 748–776 m (1 v, WAM S77661 ) . Description . Shell up to c. 25 mm high, thin, weakly inflated, somewhat prosocline, higher than wide, inequivalve, inequilateral, anterior auricles larger and longer than posterior, umbonal angle c. 100–105°; cream-brown, interior slightly darker, glossy. Both valves sculptured with about 10 unevenly spaced, rounded, scaly, primary radial costae, commencing c. 2 mm below umbo, increasing by division into c. 20 (left valve) or 30 (right valve) scaly riblets near ventral margin; furrowing interior surface weakly, apart from short, prominent furrows around ventral margin; weak, irregular, commarginal growth costae and plicae also present. Pre-radial stage almost smooth; later with intercostal antimarginal microsculpture. Auricles with 4–6 scaly riblets, weak on posterior auricles, more prominent on anterior ones. Byssal notch rather deep, byssal fasiole broad. Functional ctenolium well-developed, with 5–6 teeth. Hinge teeth weak. Dimensions . Illustrated specimen: NSW, E of Brush Island, 604 m (AM C.155798): rv: H 18.4, L 17.5 mm ; lv: H 18.1, L 17.0 mm; D 4.8 mm . Habitat . Living in the bathyal zone on soft sediment, probably byssally attached to hard objects, as shown by its well-developed functional ctenolium. Present specimens alive at 498–1006 m . Distribution . Australian temperate waters, from New South Wales (c. 33°S ) to South Australia (c. 38°S ); Tasman Sea and New Zealand (Dijkstra & Marshall, 2008: 71–72, fig. 60), as far south as SW of Cape Foulwind, NW South Island ( 42°10.0'S 170°10.0'E , 610 m , 2 v, NMNZ M.05697). Remarks . The South African species Pseudamussium gilchristi (G. B. Sowerby III, 1904 ) resembles P. challengeri in shape and colour, but lacks the intercostal antimarginal microsculpture, which is dominant in P. challengeri . The macrosculpture of both Pseudamussium challengeri and P. gilchristi is extremely variable, ranging from the smooth undulated radial riblets characteristic of the New Zealand morph of P. challengeri to a more complicated sculpture of primary radial costae and secondary riblets, which are covered with spoon-shaped lamellae (Dijkstra & Marshall, 2008: 72). Iredale (1929) and Rombouts (1991) referred Pseudamussium challengeri to Veprichlamys Iredale, 1929 , presumably because the radial microsculpture is similar to that in Veprichlamys . However, the radial macrosculpture is much more variable than in Veprichlamys , without the regular, even, narrow, widely spaced radial costae characteristic of Veprichlamys . This species more nearly resembles the type species of Pseudamussium , P. peslutrae ( Linnaeus, 1771 ) , in shape and convexity, in having weak radial sculpture, and in lacking commarginal microsculpture, at least in maturity (Dijkstra & Marshall, 2008: 72).