Leopecten pyramidesius (Ihering, 1907)
IHERING, H. VON. 1907. Les Mollusques fossiles du Tertiaire et du Crétacé supérieur de l’Argentine. Anales del Museo Nacional Buenos Aires [serie 3], 7: 1-611, pls. 1-18 [p. 375]
1907 Pecten oblongus pyramidesius Ihering, 1907
Flabellipecten
piramidesensis (Ihering); C. J. del Río, C. J. & S. A. Martínez Chiappara. 1998, Moluscos marinos miocenos de la Argentina y del Uruguay: Clase Bivalvia, plate 5, figure 3. |
«Une coquille complète de Puerto Pirámides, formation entrerienne, recueillie en 1903 par M. Fl. Ameghino, est distinguée par les côtes rayonnantes, aplaties et plus ou moins obsolètes vers les bords. Ce caractére est surtout remarquable dans la valve plane qui, dans la forme typique, a les côtes anguleuses et carénées. La coquille mentionnée a une longueur de 117 mm. et une hauteur de 102 mm. Le diamètre est de 21 mm.»
HERMANN VON IHERING, 1907
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«Examples of taxa in the Miocene and Pliocene of the tropical American region having this combination of derived features are L. boesei (Hanna and Hertlein, 1927) from the late Miocene and/or Pliocene of Baja California Sur, México (Moore, 1984, p. B72), L. macdonaldi (Olsson, 1922) from the lower Chagres (Toro Limestone Member, Woodring, 1982, p. 585), and L. pyramidesius (Ihering, 1907) and L. oblongus (Philippi, 1893) from the Upper Miocene Puerto Madryn and Paraná Formations, respectively of Argentina (del Río, 1992, 2004b).»
WALLER, T. R. 2007. The evolutionary and geographic origins on the endemic Pectinidae (Mollusca: Bivalvia) of the Galápagos Islands. Journal of Paleontology, 81 (5): 929–950. [p. 937]
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«Conchilla grande con aurículas medianas y margen dorsal auricular con una longitud comprendida entre el 48% y el 58% del largo total de las valvas. Aurículas recorridas por finas líneas radiales y líneas comarginales. Cruras auriculares marcadas y con dentilio prominente, a veces bífido, en la aurícula anterior izquierda. Valva derecha ornamentada por 24 a 27 pliegues aplanados a subredondeados, bajos y lisos. Valva izquierda con 23 a 26 pliegues bajos, ligeramente redondeados, a veces distalmente recorridos por una costillita aguda longitudinal. Ambas valvas cubiertas por líneas comarginales que se hacen notablemente más densas hacia la región ventral.
Distribución: Formación Puerto Madryn aflorante en Puerto San José Este, Salina Grande, Lote 39, Lobería Punta Pirámide y Puerto Pirámide.» DEL RÍO, C. J. & S. A. MARTÍNEZ CHIAPPARA. 1998. Clase Bivalvia. In C. J. del Río (Ed.), 1998: Moluscos marinos miocenos de la Argentina y del Uruguay. Anales de la Academia Nacional de Ciencias Exactas, Físicas y Naturales, Buenos Aires, Monografía 15: 96 p., pls. 1-26. [p. 56]
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Flabellipecten piramidesensis (Ihering, 1907); C. J. del Río, C. J. & S. A. Martínez Chiappara. 1998, Moluscos marinos miocenos de la Argentina y del Uruguay: Clase Bivalvia, plate 4, figure 1.
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«Diagnosis: Shell thick. Auricles of medium size. Dorsal margin attaining lengths of nearly 48% to 58% of total length of the disk. Surface sculptured with flat, smooth plicae on both valves.
Description: Shell large in size, attaining heights of 130 mm, thick, equilateral in outline and longer than high. Right valve slightly convex. Dorsal margin straight or a little concave towards the beak. Anterior auricle covered with 4 radial ribs and fine growth lines with free margin slightly sigmoidal in plane of commissure. Byssal notch deep in young stages and obsolete or nearly so in mature specimens. Posterior auricle sculptured with only fine growth lines and with ftee margin straight. Triangular resilial pit flattened. Two pair of auricular crura with prominent denticles. Radial sculpture of disk characterized by 24 to 27 low, smooth, flattened to subrounded plicae, wider than interspaces and somewhat subdued near ventral and lateral margins in shells attaining more than 90 mm in height. Concentric ornamentation consisting of fine and crowded lamellae, becoming stronger distally in mature shells. Left valve flat, concave near umbonal area. Auricular margin straight. Both auricles sculptured with fine growth lines and one or two radial riblets. Mature shells with a pair of auricular crura, anterior auricles of young specimens with two pairs of crura and posterior with two short crura or a bifid dentilium. Disk sculptured with 23 to 26 equidistant, low, slightly rounded, wide plicae becoming flattened distally and sometimes longitudinally ribbed by a sharp riblet. Interspaces wider than plicae. Radial flutting of the interior of both valves extends inwards about 20 mm from the ventral margin to the apical region. Comments: Flabellipecten piramidesensis [sic] (IHERING) is a rather rare taxon in the Miocene deposits of the Puerto Madryn Formation but it is locally abundant at Ea. El Fracasso (Puerto San José Este, SJE7) and at Ea. Fernández in Salina Grande, occurring in strata that also contain Chlamys actinodes (SOWERBY), Aequipecten paranensis s. str. (D'ORBIGNY) and Amusium paris n. sp. The Miocene Flabellipecten oblongus (PHILIPPI) (PHILPPI 1893, Urn. 2, fig. 4) from the Paraná Formation (Entre Ríos Province) is closely related to F. piramidesensis but has larger auricles, longer hinge margin (reaching lengths of 62 to 67% of total length), left plicae narrower with a sharp and impressed secondary rib at the top and has higher right plicae that are longitudinally deeply grooved. The Lower and Middle Miocene Flabellipecten gatunensis s.str. (TOULA) (WOODRlNG 1982, pI. 104, figs. 1-2,10) from Panama, Costa Rica, Ecuador and Venezuela differs in having shorter and smooth auricles and fewer plicae. The living Eastern Pacific Flabellipecten dieguensis [sic] (DALL (Pliocene? - Recent, Eastern Pacific, MOORE 1984, PI. 31, fig. 2, PI. 32, fig. 4) differs in having a minor number of higher and commonly longitudinally grooved ribs on both valves, deeper interspaces and in having a slightly shorter hinge line.» DEL RÍO, C. J. 1992. Middle Miocene bivalves of the Puerto Madryn Formation, Valdes Peninsule, Chubut Province, Argentina (Nuculidae-Pectinidae), Pt.I. Palaeontographica, Palaeontologie A, 225: 1-58. [p. 22, 23]
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Flabellipecten piramidesensis (Ihering); C. J. del Río, 1992, Middle Miocene bivalves of the Puerto Madryn Formation, plate 3, figure 3; plate 4, figures 1-4.
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