Conus
armentrouti (Hickman, 1980)
Description (1).
Shell moderately large for genus, biconic, with turreted spire; periphery of whorls lacking nodes or beads but sharply angled; shoulder concave above periphery and marked by faint successive indications of shallow anal notch; aperture narrow and parallel-sided; who.r abrupt narrowing and constriction at the anterior end; spiral ornamentation prominent anteriorly, becoming faint to obsolete toward periphery; relative height of spire and spiral angle variable.
Etymology. The species is named for
John M. Armentrout, whose collections at several localities in the middle
member of the Keasey Formation have aided in the completion of this study.
Dimensions of holotype.
Height 38.5 mm; maximum diameter 19.1 mm.
Material examined. Eight
specimens.
Stratigraphic distribution.
Conus armentrouti has been collected only in the upper 150 m of the
middle member of the Keasey Formation and from only a few localities.
Holotype. USNM 251437.
Figured paratypes. USNM
251438, 251439.
Type locality. Middle
member, Keasey Formation: USGS 25038.
Other localities. Middle
member, Keasey Formation: USGS 15280, 15602, 25036, 25037.
Comparison. There are few
Paleogene species of Conus with keeled, unnoded peripheries and only one
that might be confused with C armentrouti.
C.
hornii Gabb, 1864, from the type
Tejon Formation is similar to the new species, but has a more prominently channeled
shoulder and relatively lower spire. Spire height is variable in the specimens examined
(PI. 9, figs. 17, 19) and it is possible that more than one species is
represented.
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Conus armentrouti (Hickman, 1980) Pl.9 fig. 17-20 Oligocene |
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Conus asheri
length 42 mm Miocene St. Marys Formation Maryland |
Conus asheri
mm. 23 Miocene - St. Marys Formation - Maryland A cura
del Dott. Claudio Galli - Genova, Italia |
Bibliografia
Consultata
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