Semipallium dianae (Crandall, 1979)
CRANDALL, P. R. 1979. A new cone from off NE Taiwan and a new Chlamys from the Ryukyu Islands, Japan. Quarterly Journal of the Taiwan Museum, 32 (1-2): 113-115 [p. 114, figs. 3-8]
1979 Chlamys dianae Crandall, 1979
«Shell rather thin, elongated, orbicular, equivalve, ears very unequal, byssal notch shallow, both upper and lower valves slightly convex and ornamented with approximately ten equidistant radiating ribs and radial grooves respectively and also covered with fine shagreen sculpturing, also there is a stria atop each primary rib of the lower valve. Instead of scales, both valves have microscopic honeycomb network covering the entire surface. The color is extremely variable, occurring in brown, orange, red, purple and yellow; with brownish-orange the most common and lemon yellow the rarest; basic color decorated with dark bar-like markings on the ribs and fine chevron-like fine white lines between the ribs; all specimens colored orange at umbo regardless of overall shell coloration.»
P. R. CRANDALL, 1979
[fide B. K. Raines, B. K. & G. T. Poppe, 2006] |
«Habitat. Living in the littoral zone to the uppermost bathyal zone, byssally attached to the undersides of coral or amongst coral rubble on sandy bottoms.
Distribution. Western and southwestern Pacific, from southern Japan southwards to the Philippines, Indonesia and northwestern Australia, and eastwards to the Solomon Islands (Raines & Poppe, 2006: 238); Japan, Okinawa to Indonesia, 10–150 m (Huber, 2010: 206); Philippines, 20–200 m, dead; 80–120 m, alive (Raines, 2010: 632; Dijkstra, 2013: 80); Papua New Guinea (Dijkstra, 1998a: 36). Maximum depth range of live-taken specimens is 10–200 m. Present specimens from Australia dead at 3–34 m. Semipallium dianae is a new record for Australia.
Remarks. The present specimens are indistinguishable in all characters from the type material. The most closely similar congeneric species is Semipallium crouchi (Smith, 1892), known from the western Indian Ocean. Semipallium crouchi differs from S. dianae in having narrower, more prominent radial plicae and in its colour (brownish-purplish maculated, S. dianae brightly polychrome).»
DIJKSTRA, H. H. & A. G. BEU. 2018. Living scallops of Australia and adjacent waters (Mollusca: Bivalvia: Pectinoidea: Propeamussiidae, Cyclochlamydidae and Pectinidae). Records of the Australian Museum, 70 (2): 113-330, figs. 1-102. [p. 263]
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Semipallium dianae (Crandall); H. H. Dijkstra & A. G. Beu, 2018, Living scallops of australia and adjacent waters, figure 80D.
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«Type data. — Holotype (H 43.5 mm, pv) TMMT 7911, paratypes (3 pv): 1 P.R. Crandall collection, 2 T.C. Lan collection. Type locality: Japan, Ryukyu Islands, c. 30 m, alive.
Material examined. -- Philippines: PMBP 2004, Stn P4, 80-120 m, 1 v. Additional material examined. — Off Masbate, 30-50 m, alive, 2 pv (ZMA Moll. 146637); Off Batayan, 20-30 m, alive, 1 pv (ZMA Moll. 144196).
Description. — Shell up to c. 50 mm high, most specimens under 35 mm, elongate, weakly inflated, left valve slightly more convex than right, equivalve, subequilateral, auricles very unequal in size, umbonal angle 80˚-90˚; colour highly variable, brown, orange, red, purple or yellow, many specimens creamy-yellowish with brown and milky white dots and streaks. Both valves with 8-10 (most specimens with 9) evenly spaced radial costae, covered with shagreen microsculpture. Delicate radial riblets developed near ventral margin, more prominent on right valve. Anterior auricle with 5-6 radial riblets, posterior with 2-4. Hinge line straight on anterior, somewhat declined on posterior auricle. Inner surface plicate, striated near ventral margin of some specimens. Resilifer triangularly oblong, elongate. Byssal notch relatively deep, byssal fasciole broad. Functional ctenolium well-developed, with 5-7 teeth. Internal plicae with carinate riblets near margin. Hinge with weak resilial and dorsal teeth.
Distribution. — Western and southwestern Pacific, from southern Japan southwards to the Philippine Islands, Indonesia and northwestern Australia, and eastwards to the Solomon Islands and Vanuatu (ZMA, unpubl. data; Raines & Poppe, 2006: 238). Present specimen from the Philippines dead in 80-120 m. Bathymetric range of live-taken specimens is 10-30 m (ZMA, unpubl. data). Living byssally attached undersides of coral or amongst coral rubble on sandy bottoms. Remarks. — The present specimens from the Philippines are indistinguishable in all characters from the type material. The closest resembling congeneric species is S. crouchi (E.A. Smith, 1892), known from the western Indian Ocean. Semipallium crouchi differs from S. dianae in having narrower, more prominent radial costae and in its colour (brownish-purplish maculated, S. dianae brightly polychrome).» DIJKSTRA, H. H. 2013. Pectinoidea (Bivalvia: Propeamussiidae and Pectinidae) from the Panglao region, Philippine Islands. Vita Malacologica, 10: 1-108, pls. 1-32. [p. 80, 81]
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Semipallium dianae (Crandall, 1979); H. H. Dijkstra, 2013, Pectinoidea from the Panglao region, Philippine Islands, plate 21, figures 2a-2d; plate 25, figures 5a, 5b (juvenile).
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