Cyclopecten kapalae Dijkstra, 1990

Dijkstra, H. H. & Maestrati, P., 2015, Pectinoidea (Bivalvia: Propeamussiidae and Cyclochlamydidae) from the southwestern Indian Ocean, African Invertebrates 56 (3), pp. 585-585 : 619-620

Cyclopecten kapalae Dijkstra, 1990

Fig. 7H–J

Cyclopecten kapalae Dijkstra, 1990 b: 29 , figs 1–5; Dijkstra & Marshall 1997: 87, pl. 6, figs 7–12; Dijkstra

& Marshall 2008: 16, figs 14, 15A–F; Dijkstra & Maestrati 2008: 97; 2012: 393. TYpe localitY:

Australia, New South Wales, off Sydney (33°31'33"S, 152°08'07"E), - 907–914 m, live, sand ,

ooze, sediments, 10.xii.1980 (FRV Kapala , stn K80-20-08).

Description: Shell up to 6 mm in height, fragile, almost circular, slightly higher than wide, inequivalve, equilateral, left valve somewhat more inflated than right, anterior and posterior auricles dissimilar in shape and size, umbonal angle 90°–95°, dirty to milky white opaque, some specimens semi-translucent. Prodissoconch 170 µm long.

Left valve with reticulate sculpture of weak unevenly spaced radial costae and slightly more prominent commarginal lamellae, interstices microscopically scratched. Radial and commarginal sculpture commence in early ontogeny, c. 1 mm below umbonal top. Radial riblets increasing in prominence towards ventral margin. Anterior auricle with coarser commarginal lamellae than posterior one, lacking radial riblets. Right valve with commarginal lamellae, somewhat higher and coarser at ventral margin than higher up, interstices with microscopic scratches. Anterior and posterior auricles also with commarginal lamellae, slightly more irregular on anterior one. Byssal fasciole small, byssal notch hardly distinguished from outer margin of anterior auricle. Hinge line almost straight. Hinge dentition with strong irregular grooves. Internal ribs lacking.

Type material examined: Holotype (pr): AMS C.155831.1.

Paratypes (47 v): AMS C.155800, C.155813, C.155814, C.155822, C.155823, C.155831.2, C.155832, C.155837. See Dijkstra (1990 b: 31).

Other material examined: MOZAMBIQUE CHANNEL: Zambeze transect (19°36'S 36°47'E), - 636 m, live, campaign Mainbaza, stn CC3154, 13.iv.2009 ( MNHN) ; Maputo transect (25°13'S 35°21'E), - 700–707 m, live, campaign Mainbaza, stn CP3138, 10.iv.2009 ( MNHN) ; Maputo transect (23°33'S 35°55'E), - 684–698 m, dead, campaign Mainbaza, stn CP3141, 11.iv.2009 ( MNHN) ; Inhambane transect (24°22'S 35°42'E), - 708–715 m, live, campaign Mainbaza, stn CC3166, 15.iv.2009 ( MNHN) . S MADAGASCAR: Sainte Luce (24°43'S 47°32'E), - 296–307 m, dead, expedition Atimo Vatae, stn DW3534, RV Nosy Bé 11, 02.v.2010 ( MNHN) ; Lavanono (25°43'S 44°24'E), - 729–732 m, dead, expedition Atimo Vatae, stn CP3597, RV Nosy Bé 11, 12.v.2010 ( MNHN) ; S Cap Sainte Marie (26°14'S 45°09'E), - 284–286 m, dead, expedition Atimo Vatae, stn CP3615, RV Nosy Bé 11, 14.v.2010 ( MNHN) .

Distribution and habitat: Solomon Islands ( Dijkstra & Maestrati 2008: 97), southeastern Australia (Dijkstra 1990 b: 29), Norfolk Island and Kermadec Islands ( Dijkstra & Marshall 1997: 17), Vanuatu (Dijkstra & Maestrati 2012: 393). Now also extended into the southwestern Indian Ocean, from the Mozambique Channel and southern Madagascar (new record). Living bathyally (- 512–914 m) on soft substrata of mud and sand with sediments. Present specimens live at - 707–708 m (minimum depth range).

Remarks: Present specimens from the Mozambique Channel and southern Madagascar are morphologically indistinguishable from the type material. The reticulate sculpture on the left valve is somewhat variable in prominence of the present material, but this feature is also observed in material from the southwestern Pacific (MNHN).

Figures

Fig. 7 (A–J). Cyclopecten spp.: (A–G) C. kantori sp. n., holotype: campaign Miriky, stn CP3241, (A) external view of the left valve, H = 11.3 mm, scale bar = 2 mm; (B) internal view of the left valve, H = 11.3 mm, scale bar = 2 mm; (C) external view of the right valve, H = 9.8 mm, scale bar = 2 mm; (D) internal view of the right valve, H = 9.8 mm, scale bar = 2 mm; (E) prodissoconch of the left valve, H = 11.3 mm, scale bar = 0.2 mm; (F) details of the left valve, H = 11.3 mm, scale bar=0.1 mm; (G) details of the right valve, H = 9.8 mm, scale bar = 0.2 mm (MNHN 38440). (H–J) C. kapalae Dijkstra, 1990: campaign Mainbaza, stn CC3166, (H) external view of the left valve, H=5.6 mm, scale bar = 2 mm; (I) external view of the right valve, H = 4.9 mm, scale bar = 2 mm; (J) details of the left valve, H = 5.6 mm, scale bar = 0.1 mm (MNHN).