"Chlamys" wahtubbeana Dall, 1898
DALL, W. H. 1898. Contributions to the Tertiary fauna of Florida. Silex Beds of Tampa and the Pliocene Beds of the Caloosahatchie River. Part IV. I. Prionodesmacea: Nucula to Julia. 2. Teleodesmacea: Teredo to Ervilia. Transactions of the Wagner Free Institute of Science of Philadelphia, 3 (4): viii, 571-947 p., pls. 23-35 (pls. 36 and 37 in part 5, 1900). [p. 736, pl. 34, fig. 9]
1898 Pecten (Chlamys) wahtubbeanus Dall, 1898
1898 Pecten wahtubbeanus var ? willcoxii Dall, 1898
1926 Pecten biddleana Kellum, 1926
1898 Pecten wahtubbeanus var ? willcoxii Dall, 1898
1926 Pecten biddleana Kellum, 1926
W. H. Dall, 1898, plate 37.
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«Claibornian and Jacksonian Eocene of Louisiana, Alabama, and Mississippi; abundant at Wahtubbee; Burns.
Shell small, flattish, with small, unequal ears and rounded disk; fourteen or fifteen ribs carrying basally three densely finely imbricated, rounded threads, the interspaces narrower with two crenulate threads; submargins with close, fine, imbricate threads; ears prominent, with a deep, wide byssal notch, radiately imbricate with coarse, elevated radial threads; interior with shallow sulci, the cardinal crura developed but no lirae on the disk. Alt. 22, lat. 22 mm. This species differs from the Claibornian P. Deshayesii Lea by its threaded and less individualized ribs, its similarly sculptured valves, more conspicuous notch, and concentric sculpture and smaller size when adult. P. Johnsoni Clark, from the Maryland Eocene, has more numerous ribs with simpler sculpture, and which increase by intercalation instead of dichotomy. A shell which I suppose to be the same as Clark's was obtained from the Jacksonian of Clarke County, Mississippi, by Johnson. Pecten Johnsoni Clark (Bull. U. S. Geol. Surv., No. 141, p. 85, fig. 3 a, 3 b, 1896), from the Eocene of Maryland, is a young shell, not fully exhibiting the adult characters, and of which the type specimen seems worn. It belongs in this vicinity, but has twenty ribs, with single short intercalary threads, crossed only by fine lines of growth. The specimens were obtained from Potomac Creek, Va.» WILLIAM HEALEY DALL, 1898
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«Discussion: This species is especially common in the collections from MMB [Martin Marietta Berkeley quarry] and SAO [Southern Aggregates Orangeburg quarry] and previously has been reported from the Santee Limestone and "McBean Formation." The type locality is Wautubbee, Mississippi. but the original spelling of the species was with an 'h' clue to the "bad orthography of te' collector" according to Harris (1919, p. 21). Harris (ibid.) observed that "this species is extremely variable in appearance, even at the type locality." Right and left valves commonly show different sculpture, and the pattern of sculpture on a single valve may show considerable ontogenetic change.
The range of variation includes Chlamys wahtubbeana willcoxi (Dall, 1898) and Chlamys biddleana (Kellum, 1926). The type of C. biddleana is eroded, making it appear somewhat different from well-preserved specimens. Frequently, the ribs of C. wahtubbeana develop a tricarinate form, with concentric sculpture ranging from fine prickles to overlapping laminae exaggerated to the exclusion of other sculpture. Other specimens have reduced the ribs to threads. All specimens observed in this study have about 15 ribs and are somewhat longer than wide. Various authors have reported forma with more or fewer ribs: e.g., variety "tirmus" as used by Harris (1919) and Rowland (1936); "Pecten'' sp. of Ward (1985, pl. 5, fig. 1); C. gilbertharrisi Tucker (1931) (a junior homonym; renamed C. beverlyi Tucker, 1934). Judging by the lack of variation in rib number seen in C. wahtubbeana, these probably represent distinct spccies. Ward et al. (1978) and Ward and Blackwelder (1980) synonymized C. wahtubbeana with C. membranosa (Morton, 1833). As recognized by Cooper ( 1981, cited in Zullo and Harris, 1987), the latter is a distinct taxon common in the Santee and Castle Hayne Limestones. The type lot of Chlamys membranosa (Morton) consists of about a dozen specimens. They are all smaller, more circular in outline, and more convex than C. wahtubbeana, with numerous (about 40) fine, thread-like ribs. No designation of a lectotype has been found, but none are conspecific with C. wahtubbeana. I cannot tell which forms Ward et al. (1978) intended to synonymize» CAMPBELL, D. C. 1995. New molluscan faunas from the Eocene of South Carolina. Tulane Studies in Geology and Paleontology, 27: 119-152, pls. 1-9. [p. 126, 128]
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Chlamys wahtubbeana Dall; D. C. Campbell, 1995, New molluscan faunas from the Eocene of South Carolina, plate 1, figures 3-7.
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