Caribachlamys mildredae (T. Bayer, 1941)
BAYER, T. 1941. Notes on the Florida Mollusca with descriptions of two new varieties. The Nautilus, 55 (2): 43-46. [p. 46, pl. 3, figs. 16, 17]
1941 Pecten (Chlamys) imbricatus mildredae T. Bayer, 1941
T. Bayer, 1941, plate 3.
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«Left valve rayed with eight rather prominent ribs and from 1 to 3 interstitial smaller ribs between each major rib. Large and small costae armed with elevated scales placed at regular intervals. Lower valve rayed with rather prominent scaly ribs in groups which correspond to the major ribs on the upper valve. Auricles unequal, with seven teeth in the byssal aperture. Color, ranging from a brilliant red flecked with white, through brownish-purple mottled with paler tan, to pure white. Holotypee pale brown, purple tinted at the margin, with spots of darker brown between the major costae. Lower valve pale tan or fawn, vrith faint suggestion of spotting. Interior yellow with clear purple at the margins and at the hinge. Alt. 37.5 mm.; lat. 32 mm.
Several factors link this shell with imbricatus: one is the similar scheme of ribbing; the enlarged, sometimes cupped scales; the yellow and purple interior; and the large size of individuals. Unfortunately, the type material selected by Frampton is not available. The shell ranges from Biscayne Bay to the Tortugas and the Bahamas. Holotype cat. 02948 in the author's cabinet; paratypes in collection of W. A. Royce. Named in honor of Mrs. W. A. Royce, who first collected it.» TED BAYER, 1941
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«In his original description of Pecten (Chlamys) imbricatus mildredae, Bayer (1941: 46) gave as his basis for linking the new taxon to P. imbricatus "the similar scheme of ribbing; the enlarged, sometimes cupped scales; the yellow and purple interior; and the large size of individuals." He did not, however, describe any intergradation between the two taxa, nor did he mention any ecological or geographic separation, both of which would be expected if the two taxa are indeed subspecies. Bayer (1943: 110) later elevated his new "variety" to species rank, while still maintaining that P. imbricatus is its closest relative.
Abbott (1974: 443) mentioned that Chlamys mildredae "may be a hybrid between sentis and ornata" but gave no reason why hybridization should not be between Caribachlamys sentis and C. imbricata, the latter being the species to which Bayer thought C. mildredae to be most closely related. At any rate, the hybridization hypothesis seems to have little merit. C. mildredae shows no more variation than do associated species; there is no indication of a "hybrid swarm" such as is known to occur commonly in hybridizing situations. It seems more likely, particularly in view of the new species C. paucirama described above, that C. mildredae is a relict species and that its morphology represents an early stage in the evolution of the C. imbricata lineage. This could also explain its present-day rareness and its limited geographic distribution.» WALLER, T. R. 1993. The evolution of Chlamys (Mollusca: Bivalvia: Pectinidae) in the tropical western Atlantic and eastern Pacific. American Malacological Bulletin, 10 (2): 195-249. [p. 226]
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Caribachlamys mildredae (Bayer, 1941); T. R. Waller, 1993, The evolution of Chlamys, figures 9c-9e.
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