Parvamussium araneum Dijkstra, 1991

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 : 131

Parvamussium araneum Dijkstra, 1991

Figs 5, 6A–D,F,K

Parvamussium araneum Dijkstra, 1991: 8 , figs 3–10; Dijkstra & Kastoro, 1997: 255, figs 30–38; Dijkstra, 2001: 82; Dijkstra & Maestrati, 2008: 85; Dijkstra, 2011: 40, pl. 1015, figs 1a–b; Dijkstra, 2013: 17, pl. 2, figs 2a–b, 3a–b, pl. 4, figs 6a–b.

Type data. Holotype (pr) RMNH 56531 , 6 paratypes (1 pr + 5 v) RMNH 56532 , RMNH 56533 . Type locality: Indonesia, NE of coast of Sumba , E of Melolo, 9°51.8'S 120°46.4'E, alive, 240 m (SNELLIUS-II stn 4.060).

Additional material examined. — AUSTRALIA: QUEENSLAND: 18.5 ml E of North Reef , 23°11.5'S 152°14.5' E, alive, 188 m (13 v, C.165518).

For additional material examined from Indonesia see Dijkstra (1991: 8) and Dijkstra & Kastoro (1997: 255), and for Vanuatu see Dijkstra (2001: 82).

Description. Shell up to c. 9 mm high, weakly convex, circular, auricles unequal, umbonal angle c. 105°, hyaline to opaque, milky-white.

Left valve with c. 25 evenly spaced radial costae, increasing in number near ventral margin, crossed by commarginal lamellae, less conspicuous than costae (forming reticulate sculpture), with spines at intersections. Near umbonal area only commarginal lamellae present, with delicate interstitial irregular threads. Identical sculpture on auricles.

Right valve sculptured with evenly spaced commarginal lamellae, more close-set near umbonal area, with interstitial scratches.Auricles with irregular reticulate sculpture. Byssal notch narrow.

Inner surface of both valves with 3 rudimentary riblets, one additional on posterior auricle. Dorsal margin straight. Resilifer triangular.

Habitat. Living on the outer continental shelf and in the bathyal zone, byssally attached or free on sediment (rubble, sand or mud).

Distribution. Indonesian Archipelago, 240–300 m (Dijkstra, 1991; Dijkstra & Kastoro, 1997); Philippines, 201–357 m (Dijkstra, 2011, 2013); Vanuatu, 154–179 m (Dijkstra, 2001); Fiji, 567–699 m; Tonga, 523–806 m; Solomon Islands , 194–286 m (dead) (Dijkstra & Maestrati, 2008). Maximum depth range of live-taken specimens is 154– 699 m. Present specimens from Australia (Queensland) living at 188 m.

Figure 5. Distribution of Parvamussium araneum Dijkstra (circle), P.

conspectum Dijkstra & Kastoro (star), P. lamprelli sp. nov. (triangle) and P. maorium Dell (squares).

Remarks. The present specimens from Queensland are identical to the type specimens of Parvamussium araneum from Indonesia.

Parvamussium araneum is a new record for Australia.