Nodipecten 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. [p. 695]
«Section Nodipecten Dall, 1898. Type P. nodosus L.
Shell like Lyropecten, but the ribs intermittently nodose, with more or less prominent hollow nodes or bullae ; radial striation pronounced; ears unequal, the posterior smaller, the valves often more or less oblique; imbricate surface layer sometimes very marked.»
WILLIAM HEALEY DALL, 1898
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Pecten nodosus Linnaeus; L.A. Reeve, 1852-53, Monograph of the genus Pecten, Conchologia Iconica, plate 3, figure 15.
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Nodipecten nodosus (Linnaeus, 1758); T. R. Waller, 2011, Neogene Paleontology of the Northern Dominican Republic, plate 18, figures 5-9.
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«Pecten (Nodipecten) Dall, 1898: 695.
Chlamys (Nodipecten) Dall. Hertlein, 1969: N360. Lyropecten (Nodipecten) Dall. Abbott, 1974: 448. Nodipecten Dall. Smith, 1991b: 86. Type species.— Ostrea nodosa Linnaeus, 1758, by original designation (Dall, 1898: 695), Recent, tropical western Atlantic from the Antilles southward throughout the Caribbean to Brazil (Smith, 1991b).
Original diagnosis.— "Shell like Lyropecten, but the ribs intermittently nodose, with more or less prominent hollow nodes or bullae; radial striation pronounced; ears unequal, the posterior smaller, the valves often more or less oblique; imbricate surface layer sometimes very marked" (Dall, 1898: 695).
Emended diagnosis.— Monophyletic clade derived from Lyropecten having ledges and nodes in commarginal rows, especially pronounced on LV; nodes either open and flaring or closed, hollow, and bulbous; key ribs of LV higher and wider than neighboring ribs, commonly with a central-sector pattern of N r Nc r N or N 2r Nc 2r N; interspaces of RV corresponding to key ribs of LV wider and deeper than neighboring interspaces; commarginal lamellae coarse, not close-set; hinge dentition consisting of three pairs of teeth (modified from Waller, 2007: 933).
Remarks.— Species of Nodipecten are distinguished on the basis of shell shape, rib patterns, secondary costation on disk, disk flanks and byssal fasciole, and form and distribution of flanges or nodes. (See the Methods and Materials section for an explanation of rib-pattern annotation.)
Smith (1991b) and Waller (2007) used different concepts of Lyropecten and Nodipecten in their phylogenetic interpretations. According to Smith (1991b: 48), Lyropecten differs from Nodipecten in having auricles of more equal length, a shallower byssal notch, and more regularly spaced ribs that are less diffentiated in height (i.e., with less distinct key ribs). Her concept included forms with a central-sector pattern of N 2r Nc 2r N in Lyropecten, but including forms with a pattern of N r Nc r N in Nodipecten. Following this distinction, she included species such as N. colinensis s. l. of the Caribbean Miocene and Pliocene and the extant N. magnificus of the Galápagos Islands in Lyropecten. Waller (2007), in contrast, regarded Lyropecten as the more plesiomorphic genus and distinguished Nodipecten on the basis of its derived characters, including repeated nodes and ledges, nodes in the form of open flanges or closed but hollow bulbs, and coarse secondary costae on disks (Waller, 2007: fig. 3, node 7). According to Waller's concept, both N. colinensis and N. magnificus belong in Nodipecten, not Lyropecten. The evolution of Nodipecten has been discussed in detail by Smith (1991b), Del Río (2006), and Waller (2007), but there is still much to learn, particularly with regard to the great amount of variation shown by several species and stratigraphic correlation between the eastern and western sides of the Americas. Geographic range.— Presently living in the western Atlantic regions from North Carolina to Florida and Bermuda, throughout the Gulf of Mexico and Caribbean, to as far south as Brazil and Ascension Island, and in the eastern Pacific from the Gulf of California to Peru, commonly off shore from shallow water to mid-shelf depths (Abbott, 1974; Coan et al., 2000).
Stratigraphic range.— Lower Miocene to Recent (Waller, 2007).»
WALLER, T. R. 2011. Neogene Paleontology of the Northern Dominican Republic. 24. Propeamussiidae and Pectinidae (Mollusca: Bivalvia: Pectinoidea) of the Cibao Valley. Bulletins of American Paleontology, 381: 1-197 [p. 119-121]
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