Similipecten redferni Dijkstra, 2002
DIJKSTRA, H. H. 2002. A new species of living glass-scallop, genus Similipecten (Bivalvia, Propeamussiidae), from the Bahama Islands (West Indies) (Studies on West Indian marine molluscs nr. 35). Basteria, 66 (4-6): 189-192, figs 1-5, table 1 [p. 191, figs. 1-6]
2002 Similipecten redferni Dijkstra, 2002
H. H. Dijkstra, 2002, figures 1-5.
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«Cyclopecten sp.; Redfern, 2001: 213, pl. 88 figs 872A (holotype), 872B-D (paratypes).
Material examined (paratypes, unless indicated otherwise). — Bahama Islands, Abaco Island, N of northwest-end of Guana Cay, c. 26°44'N 77°09'W, shells only, at various depths amongst sediment, C. Redfern leg.: 60 m, 06.viii.1982, 1 rv (CR); 53 m, 15.vii.1983, 3 lv + 3 rv (CR); 45 m, 17.viii.1983, 1 rv (CR); 52 m, 09.ix.1987, 1 lv (holotype, ZMA Moll. 4.02.033),3 lv + 3 rv (ZMA Moll. 4.02.034), 15 lv + 13 rv (CR); 52 m, 15.viii.1989, 3 lv + 1 rv (CR); 35 m, 28.vi.1996, 4 lv + 4 rv (CR).
Description. — Shell up to c. 4.5 mm in height, fragile, moderately thin, semi-transparent or opaque, rather circular in shape, inequivalve, slightly inequilateral, right valve more convex than left valve, auricles inequal in shape and approximately equally sized, mottled with hyaline dots or with withish or brownish dots and patches, internal ribs lacking. Prodissoconch c. 92 μm.
Left valve rather flattened, somewhat oblique and slightly concave posteriorly with a sinuous ventral margin, weakly sculptured with numerous delicate radial riblets (c. 10 in the central part of the disc), commencing in early growth stage (c. 1 mm below the umbonal top) and increasing and extending to the ventral margin. Fine commarginal threads are produced in preradial stage, forming a somewhat reticulate sculpture in early radial stage. Anterior auricle somewhat curled on the anterior side, with prominent commarginal lamellae, posterior auricle sculptured radially or weakly reticulated. Right valve rather inflated, nearly smooth with a microsculpture of commarginal lines, with posterior auricle continuous with disc and demarcated slightly curved anterior auricle with delicate radial sculpture or faintly reticulated. Byssal notch and fasciole small and narrow, ctenolium lacking. Resilifer triangular, cardinal crura rather broad with irregular transverse incisions. Measurements of the holotype: H 4.75 mm, W 5.01 mm. Distribution. — So far only known from the Bahama Islands, depth range 35-60 m, amongst sediments. Comparison. — The present species is morphologically close to Similipecten nanus (Verrill & Bush, in Verrill, 1897), known from the tropical and sub-tropical western Atlantic, but differs in having a more inflated and inequilateral left valve (posteriorly oblique, S. nanus more equilateral and more circular). The radial sculpture of the left valve is more prominent, which is weaker or even lacking in S. nanus. Other characters are almost similar. Etymology. — The present species is named after Mr. Colin Redfern, who collected this new glass-scallop and recently provisionally recorded it in his comprehensive monograph on the Bahamian seashells.» HENK H. DIJKSTRA, 2002
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