Argopecten ameleus (Woodring, 1925)
WOODRING, W. P. 1925. Miocene mollusks from Bowden, Jamaica. Pelecypods and scaphopods. Carnegie Institution of Washington Publication 366: 222 pp. [p. 70, pl. 8, fig. 9]
1925 Chlamys (Plagioctenium) ameleus Woodring, 1925
W. P. Woodring, 1925, plate 8.
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«The following is a description of this species:
Shell small, subequivalve, suborbicular, the two valves equally inflated; both valves sculptured with 21 to 23 strong, subrounded ribs, separated by narrower interspaces; concentric sculpture of fine lamellae usually appears in interspaces and occasionally on ribs, absent on submargins; auricles unequal, both bearing inconspicuous radials; on the posterior auricle the radials are more prominent ventrally, but on the anterior auricle they are broader and stronger dorsally, overridden by fine concentric lamellae, coarser and more irregular on the anterior auricle. A right valve: length 15 mm.; height 14.8 mm.; diameter.; 3.2 mm.; length of hinge 8 mm. A left valve: length 13.5 mm.; height 13.2 mm.; diameter 3.5 mm.; length of hinge 6.2 mm. Some shells are slightly less rounded than the holotype. On some shells a slight groove lies on the extreme lower part of a few ribs. Type material: Holotype (right valve, U. S. Nat. Mus. No. 352785)». WENDELL PHILLIPS WOODRING, 1925
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«Comparisons.— Argopecten ameleus resembles the early ontogenetic stages of A. eccentricus eccentricus in having smooth, gently rounded rib crests on the right valve. Compared to that subspecies, however, A. ameleus lacks any sign of crestal troughs even on the largest specimen. It also has more prominent commarginal lamellae in rib interspaces and a deeper byssal notch with a more prominent active ctenolium. The posterior margin of the right posterior auricle of A. ameleus is more deeply sigmoidal and more strongly costate, and the free margins of the right auricles commonly form a less obtuse angle where they meet the dorsal margins. Argopecten ameleus differs from the stratigraphically lower forms of A. thetidis in having more rounded ribs and a much less extensive foliated-calcite re-entry and in lacking any sign of troughs on rib crests. Compared to the holotype of A. ameleus from the Bowden Formation of Jamaica, the Dominican Republic specimens have at least one less rib. Compared to A. uselmae of the Bowden Formation, A. ameleus lacks rib crests that overhang the rib flanks and has a considerably broader umbonal angle and more numerous ribs (20-22 compared to 17-18). Compared to extant A. nucleus (Born, 1778), A. ameleus lacks strong radial costae on its disk flanks, is less gibbous, and has posterior auricular margins that form a less obtuse angle with the dorsal margins.
Evolution.— Because Argopecten ameleus is thus far known only from 9 valves from the Dominican Republic and 3 valves from Jamaica, evolutionary trends cannot be discerned with any confidence. The only difference between specimens from the Mao Formation of the Dominican Republic and the slightly younger Bowden shell bed (compare Saunders et al., 1986: text-fig. 39 and Kohl & Robinson, 1998: 39) is a slight increase in the number of ribs in the latter. The origin of the species is unknown. Occurrence.— In the Dominican Republic, Argopecten ameleus occurs in the Mao Formation (Mao Adentro Limestone Member?) near Guayabin and possibly in the upper Gurabo Formation north of El Limpio, of Pliocene age. Distribution.— Outside of the northeastern Dominican Republic, Argopecten ameleus is known only from the Bowden Formation of southeastern Jamaica». 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. 42]
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Argopecten ameleus (Woodring, 1925); T. R. Waller, 2011, Neogene Paleontology of the Northern Dominican Republic, plate 4, figures 5-10.
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