Antillipecten Waller, 2011
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, pls. 1-18. [p. 112]
«Genus ANTILLIPECTEN n. gen.
Type species.— Pecten antillarum Récluz, 1853, extant in the tropical western Atlantic, type locality Pointe-à-Pitre, Guadeloupe (Récluz, 1853: 153).
Diagnosis.— Small, nearly equivalved or slightly right-convex Decatopectinini with deep byssal notch, low to moderately strong internally carinate radial ribs, common secondary radial costae on ribs and in interspaces, weak to absent radial costae on posterior auricles, and close-set commarginal lamellae on ribs and in interspaces throughout ontogeny; hinge dentition lacking clear resilial and intermediate teeth.
Etymology.— The prefix Antilli- refers to the common occurrence of the new genus in the Antillean region; the suffix indicates its placement in the family Pectinidae.
Remarks.— Pecten antillarum of the tropical western Atlantic region has been assigned previously to the genera Lyropecten or Bractechlamys Iredale, 1939. The species is clearly not a Lyropecten in that it lacks the strong three-element dentition of that genus and differs in microsculptural features. Specifically, P. antillarum has typical decatopectinine close-set commarginal lamellae (defined by Waller, 1986, as 30-70 lamellae per 2-mm distance along a radius in center of disk at 10 mm height) and a nearly smooth left preradial zone, whereas Lyropecten (and the related genus Nodipecten) have only far-set commarginal lamellae and a preradial zone that is commonly pitted or with antimarginal striae (Smith, 1991b: fig. 8). Pecten antillarum closely resembles the Indo-Pacific decatopectinine genus Bractechlamys in shape and ribbing but differs from all known members of that genus in lacking intermediate hinge teeth. This difference in dentition is a persistent feature of Antillipecten throughout its long geologic history in the tropical western Atlantic since at least the early Oligocene.
The need for a genus-level name for this group was anticipated by Mansfield (1937: 207), who observed that his new species Chlamys (Aequipecten) flintensis Mansfield, 1937, is in the same group as Pecten vaun Cooke, 1921. Without being able to determine the section to which such species belong, Mansfield placed these species in “the section Aequipecten” with a query. The new genus Antillipecten ties these species to a larger group of tropical American Decatopectinini that possesses close-set commarginal lamellae throughout ontogeny, lacks significant radial costae on disk flanks, lacks intermediate hinge teeth, and lacks significant ledging. Based on the examination of extensive collections at the Smithsonian Institution, at least the following species in addition to the type species are assigned to Antillipecten, beginning with the geologically oldest: Chlamys (Aequipecten?) flintensis Mansfield, 1937, Suwannee Limestone (sensu Huddlestun, 1993: 70), early Oligocene (Vicksburgian), Florida; Pecten anguillensis Guppy, 1867, of Cooke (1919), Antigua Formation, late Oligocene, Antigua; Pecten willobianus Cooke, 1919, Antigua Formation, late Oligocene, Antigua; Pecten guanicus Maury, 1920, Juana Díaz Formation?, Oligocene?, Puerto Rico; Pecten (Plagioctenium?) gardnerae Cooke, 1919, of Mansfield (1937), not Cooke, Chattahoochee Formation, early Miocene, Florida; Pecten (Chlamys) alumensis Dall, 1898, Chipola Formation, late early Miocene, Florida; Pecten vaun vaun Cooke, 1921, Anguilla Formation, late early to early middle Miocene, Anguilla; Pecten cercadica Maury, 1917a, Cercado Formation, late Miocene, Dominican Republic; Pecten gardnerae Cooke, 1919, La Cruz Formation, Pliocene, Cuba; Pecten vaun flabellum Cooke, 1921, La Cruz Formation, Pliocene, Cuba; and Chlamys (Chlamys) bellipictus Woodring, 1925, Bowden shell bed, late Middle Pliocene, Jamaica. Chlamys reynali Mongin, 1968, from the Miocene of Guadeloupe is another Antillipecten based on the figures in Mongin (1968). Anatipopecten Hertlein, 1936, is another decatopectinine genus restricted to the Americas. Pecten anatipes Morton, 1833, the type species, is confined to the early Oligocene (Vicksburgian; Huddlestun, 1993: 77) of the Gulf of Mexico Coastal Plain. It differs from Antillipecten in having a commonly well-developed three-element hinge dentition and costate disk flanks, as well as enhanced development of commarginal ledging and well-developed radial costae on posterior auricles. Chlamys (Lyropecten) incertae Tucker-Rowland, 1938, from the upper Eocene or lowermost Oligocene of the northern Florida Peninsula, was placed in Anatipopecten by Nicol et al. (1989), but it differs from the type species in having a weaker hinge dentition and commonly absent secondary radial costae on the disk, with only very faint radial costae or none on its disk flanks. On the basis of these characters, it could equally be regarded as a very early Antillipecten. Antillipecten differs from Flexopecten, an extant genus of the Mediterranean and eastern Atlantic, in the early ontogeny of shell microsculpture. Flexopecten has a pitted left beak, with pits commonly extending just beyond the start of radials, whereas Antillipecten has a smooth early left dissoconch followed by fine antimarginal microsculpture, which in turn abruptly terminates at the start of the close-set commarginal lamellae. Molecular genetic studies indicate that Flexopecten is phylogenetically closer to Aequipecten than to the Decatopectinini (Waller, 2006a, and references therein). Geographic and stratigraphic ranges.— Early Oligocene to present, Caribbean and tropical western Atlantic.»
THOMAS RICHARD WALLER, 2011
|
Antillipecten antillarum (Récluz, 1853); T. R. Waller, 2011, Neogene Paleontology of the Northern Dominican Republic. 24. Propeamussiidae and Pectinidae (Mollusca: Bivalvia: Pectinoidea) of the Cibao Valley, plate 16, figures 1-5.
Pecten Antillarum, Recluz; C. A. Récluz, 1853, Description de coquilles nouvelles (G. Pecten, Tellina et Natica), plate 5, figure 1.
|