Conus
cacuminatus (Spieker, 1922)
Shell large, moderately heavy ; the spire of medium height, and the body
whorl tapering gracefully in a straight-sided cone. Whorls 9-10 in number; the
2 ˝ nuclear whorls smoothly convex, and
the remainder concave, with a smooth keel at the outer edge just above the
suture. Sculpture of lines of growth, arcuate on the whorls of the spire,
straight on the body whorl and lamellose in worn specimens. The best preserved
specimen shows numerous very faint spiral striae on the whorls, with a faintly
impressed spiral line at the deepest point of the concave whorl-surface. Near
the base of the body whorl are six to eight spiral cords with narrower
interspaces; these are most prominent just inside the aperture. The shoulder of
the body whorl is sharp, and the sides descend from it, with very little
convexity, in straight lines. The aperture is somewhat wide (1).
Height, 73 ;
diameter, 38,5 mm.
A number of specimens of this graceful cone occur in Nelson's collection, and a
cast in the Singewald collection from the Upper Zorritos formation is
questionably identified with it. It is similar to Conus molis Brown and
Pilsbry, of the Gatun fauna, differing from that species in having straighter
sides, lacking the prominent spiral striae on the body wrhorl, and in having a
proportionally higher spire. It is a much smaller form (1).
It differs from
C. molis var. bravoi, of the local fauna, as noted in the remarks on
that variety (1).
Upper Zorritos ( ?). Quebrada de las Alturas.
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Conus cacuminatus (2)
Plate 12 fig. 1 USNM 643429 mm. 102,0 x 57,7 Pliocene Punta Gorda - Ecuador |
Conus cacuminatus (1)
Plate I fig. 5 mm. 73,0 x 38,5 Upper Zorritos Formation (Miocene) Perů |
Conus cacuminatus (2)
Plate 12 fig. 1b mm.
68,5 Pliocene Zona J – Punta
Blanca - Ecuador
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Conus cacuminatus
Middle Miocene - Ferrotepec Formation Messico |
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Bibliografia Consultata
·
(1) - Spieker, E. M., 1922. The Paleontology of the Zorritos Formation
of the North Peruvian Oil Fields. Johns Hopkins University Studies in
Geology, 3: 1 -196
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(2) - Olsson, A. A., 1964. Neogene Mollusks from Northwestern
Ecuador