Chlamys coatsi middletonensis MacNeil, 1967
MACNEIL, F. S. 1967. Cenozoic pectinids of Alaska, Iceland, and other nothern regions. United States Geological Survey Professional Paper, 553: iv, 57 p., pls. 1-25. [p. 18, pl. 13, figs. 3-5, 7; pl. 14, fig. 8; pl. 15. fig. 8]
1967 Chlamys ("Chlamys") coatsi middletonensis MacNeil, 1967
F. S. MacNeil, 1967, plate 13.
F. S. MacNeil, 1967, plate 14.
F. S. MacNeil, 1967, plate 15.
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«Discussion.— This subspecies differs from typical C. coatsi by having less discrepant juvenile and adult sculpture. The plications show less relief in C. c. middletonensis, almost none in some specimens, and the secondary riblets on the right valve usually extend to the beak; only an occasional plication is smooth. The left valve of C. c. middletonensis is more elegantly and more precisely sculptured; the ribs are divided into primary, secondary, tertiary, and quaternary ribs, the finest ribs tending to be neatly beaded towards the margins. Specimens from Amchitka show the original color; the left valve is bright red, the right valve pale pink or white. Typical C. coatsi from the same locality is mottled red or has irregular concentric red bands. The possible relationships of this subspecies were discussed under typical C. coatsi.
Types: The holotype (USNM 644915), an unseparated pair of valves, measures 66 mm in height, 59 mm in length. Other figured specimens are numbered USNM 644916-644919. Type locality: From about the top of Miller's measured section (1953, p. 23) on Middleton Island, Alaska, USGS M1741. The horizon is about 1,400 ft above the top of the Chlamys (Leochlamys) tugidakensis zone. Other occurrences: South Bight, Amchitka Island, USGS D46; possibly from an upper horizon.» FRANCIS STEARNS MACNEIL, 1967
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