Bractechlamys Iredale, 1939
IREDALE, T. 1939. Mollusca. Part 1. In: Great Barrier Reef Expedition 1928-29, B.M.(N.H.), Scientific Reports, 5 (6): 209-425, pls. 1-7. [p. 366]
«Genus Bractechlamys nov.
Type: B. evecta sp. nov.
Shell small, somewhat strongly convex, strongly ribbed; valves subequal, one valve usually plain, the other coloured and blotched, but sometimes both valves are coloured; valves subequilateral, stout, ears subequal.
The apex is smooth, but soon plain radial ribs arise, and these develop into broad, rounded, compound ribs, with narrower deep intervals. The early shell is covered with very fine, practically microscopic, concentric threads, quite unlike the longitudinal scratching of Complicachlamys, and like the fine sculpture of Juxtamusium, than which the adult shell could not be more unlike. This fine sculpture persists on the top of the major compound ribs, but the edges and interstices produce a series of radial rows of minute scallops. There is a small byssal sinus and a remnant of a ctenolium, which sometimes disappears altogether. There are no auricular crura, but a nodule appears at the base of the posterior ear. The hinge line is very stout, three well-marled cardinal crura being present and all strongly denticulate; the ligamental pit broad and short, the ligament itself narrow. The ventral edges of the valves thin and strongly clasping, in accord with the external ribbing.» TOM IREDALE, 1939
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Bractechlamys evecta sp. nov.; T. Iredale, 1939, Mollusca, Great Barrier Reef Expedition 1928-29, plate 5, figures 20, 20a.
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Bractechlamys vexillum (Reeve); H. H. Dijkstra & A. G. Beu, 2018, Living scallops of Australia and adjacent waters, figures 32B, 32F, 32H.
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«Bractechlamys Iredale, 1939
Bractechlamys Iredale, 1939: 366. Type species (by original designation): Bractechlamys evecta Iredale, 1939 (= Pecten vexillum Reeve, 1853). Recent, 0.5 ml SE of Lizard Island, QLD, 19 fathoms [35 m]; widespread in tropical western Pacific.
Diagnosis. Decatopectinini with 8–15 primary radial plicae, some species with nodules on plicae; with secondary radial riblets; shape oblong to subcircular; with prominent intermediate teeth, a relatively deep byssal notch, prominent costae on auricles, and an obsolete ctenolium.
Distribution. Recent. Tropical Indo-West Pacific and eastern Atlantic, living in the littoral to sublittoral zones amongst coral rubble on soft sediment.
Discussion. Grau (1959: 120) and subsequently Hertlein (1969: N366) treated Bractechlamys, together with Comptopallium Iredale, 1939 and Complicachlamys Iredale, 1939, as junior synonyms of Semipallium Jousseaume in Lamy, 1928 in the Decatopecten group. Waller (1972a: 245) pointed out that Semipallium has reticulate (“shagreen”) microsculpture, lacking on Bractechlamys and its relatives, and belongs in tribe Pedini. At present Bractechlamys is treated as a valid genus, placed in Decatopectinini by Waller (1986: 40).»
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. 181]
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