Cryptopecten nux (Reeve, 1853)

Dijkstra, H. H. & Kilburn, R. N., 2001, The family Pectinidae in South Africa and Mozambique (Mollusca: Bivalvia: Pectinoidea), African Invertebrates 42, pp. 263-321 : 310-312

Cryptopecten nux (Reeve, 1853)

(Figs 50–51)

Pecten nux Reeve, 1853 : pl. 32, fig. 143, erratum .. Type locality: Panglao , Bohol, Philippines (des. Wagner 1989).

Cryptopecten nux ; Wagner, 1989: 56, figs 6–9 (lectotype) 17–18; Dijkstra & Marshall, 1997:107 (references, synonymy, type data, distribution); Dijkstra & Knudsen, 1998: 86 (further references and synonymy, pl. 3, figs 12–13).

Cryptopecten nux nux ; Hayami, 1984: 100, pl. 2, fig. 4, pl. 3, figs 1–2, pl. 9, figs 2–5, pl. 12, figs 1–2 (references, synonymy, type data, description, distribution, discussion).

Pecten guendolenae Melvill, 1888: 279 , pl. 2, fig. 6. Type locality: Mauritius.

Chlamys guendolenae ; Wagner, 1989: 58, figs 10 (holotype), 11–13, 17–18 (description, discussion).

Chlamys bullatus (non Dautzenberg & Bavay, 1912); Barnard, 1962: 254; idem, 1964: 429, fig. 14c; idem, 1974: 760.

Chlamys (Cryptopecten) bernardi (non Philippi, 1851); Oliver, 1992: 72, 76, text figs 21a–b, pl. 14, figs 3a–b.

Description: Shell height to 20 mm high (average 10–15 mm), solid, RV more convex than LV, orbicular to suborbicular, equilateral to inequilateral, auricles unequal, umbonal angle ca. 90°. Both valves with 18–22 regularly spaced, vesicular sculptured radial ribs, when worn appearing more tripartite, internals with commarginal lamellae.Auricles with 4-6 spiny sculptured radial ribs, strongest on anterior auricle of RV. Hinge line straight. Byssal fasciole moderately wide, byssal notch deep.Active ctenolium with 4– 6 teeth on suture. Inner surface crenulated near periphery. Cardinal crura well developed. Resilifer triangular, slightly oblique. Colour strongly variable, whitish, creamy or yellowish with red, pink, purple or brown maculations, LV more strongly pigmented, sometimes uniform yellow or purple.

Type material: see Dijkstra & Knudsen (1998).

Regional data (all NMSA: NMDP, unless otherwise stated, selected records only): SOUTH AFRICA: Zululand: NE of Kosi Bay, 65 m, fine sand, dead (S6725); off Kosi Bay, 45 m, fine muddy sand, dead (D6040); same loc., 52 m, lithothamnial pebbles, algae, dead (S7805); SE of Kosi Bay, 41 m, lithothamnial pebbles, coarse sand, dead (S7385); same loc., 40 m, fine sand, dead (D8783); same loc., 50 m, fine sand, shell rubble, Codium , live (D7311); same loc., 50 m, fine, slightly muddy sand, dead (D8322); off Boteler Point, 70 m, coral rubble, dead (D6416); same loc., 70 m, some coarse sand, some shell rubble, dead (D7413); same loc., 44 m, sponges, shell, dead (S4476); same loc., 58–61 m, sand, pebbles, dead (S4209); SE of Rocktail Bay, 60 m, coarse sand, dead (S5271); NE of Lala Nek, 66–71 m, coarse sand, sandstone rocks, dead (S6109); NE of Lala Nek, 60 m, coarse sand, dead (S5579); off Lala Nek, 75 m, coarse sand, sandstone, coral, dead (S5843); SE of Lala Nek, dredged, dead, 74 m, sandstone rocks, dead (S7244); off Hully Point, 50 m, fine sand, live (D7554); off Gobey’s Point, 55–60 m, sand, shell rubble, live (D7175); off Sodwana Bay, 70-120 m, dead (D1513: A. D. Connell); same loc., 70 m, coral rubble, dead (S3899); same loc., 70 m, dead coral

50 51

Figs 50–51. Cryptopecten nux (Reeve, 1853) : NMSA D7311 , SE of Kosi Bay, Zululand , 50 m, pv, 15.5 x 15.9 mm. 50. LV exterior. 51. RV exterior .

rubble, dead (S4561); same loc., 49–53 m, sand, live (S4754); SE of Sodwana Bay, 64 m, sand, live (S4419); off Matigulu River mouth, 70 m, coarse sand, broken shell, dead (S744). Natal: off Sheffield Beach, 50 m, fine sand, dead (E9598); off Durban, 50 m, dead (B4106:A. D. Connell); off Amanzimtoti, 115–125 m, medium sand, dead (D1264); same loc., 160–170 m, medium sand, dead (D1485); off Mtamvuna River, 45 m, fine sand, gorgonians, dead (D3700). Transkei: SE of Mtamvuna River, 50 m, fine sand, dead (D3653); off Nthlonyane River, 80 m, sand, broken shell, dead (C2586); off Mendu Point, 250–260 m, coarse sand, dead (C4939); off Sandy Point, 90 m, calcareous debris, coarse sand, dead (C4532); off Qolora River, 96 m, gorgonians, sponges, dead (C4656); off Kei River, 138 m, coarse sand, dead (C5084).

Distribution: Throughout tropical and subtropical Indo-West Pacific (absent from Hawaii), south-western limit western Transkei.

Habitat: Living byssally attached to rocks or coral, or on sediments or coral rubble on sandy bottoms at littoral to bathyal depths.

Remarks: C. nux is rather variable in outline, convexity, sculpture and colour ( Hayami 1984:100; Dijkstra 1991: 37). Type material of P. guendolenae , C. smithi and C. corymbiata is morphologically similar to C. nux . Wagner (1989: 58) considered C. guendolenae to be a valid species, but Hayami (1984: 102) and Dijkstra (1991: 37) regarded it as a synonym of C. nux . C. bernardi ( Philippi, 1851) from French Polynesia is larger in size (up to 25 mm high), more triangular in shape (when mature) and more convex, and has finer sculpture than C. nux . However, it is possible that the type material of C. nux consists of young specimens of C. bernardi . Similar material has been observed from French Polynesia (HD, MNHN, NNM, ZMA) (under study).

South African material, misidentified by Barnard (1964: 429) as ‘ Chlamys bullatus Dautzenberg & Bavay’, is in all features similar to C. nux .