Conus
riosantiagensis (Olsson, 1964)
The
shell is of medium or large size, solid, with an almost flat spire or five plus
whorls, the apex although much corroded in the specimens rises like a small
sharp pimple in the middle. The dorsal surface, or that of the subsutural
fasciole, is a wide, flat area, bounded on the outer side by a slightly raised
margin, and marked by growth lines showing a shallow, concave form, the whole
overrun by weak subobsolete spirals. The shell is widest just below the
shoulder formed by the edge of the subsutural fasciole, the profile of the body
whorl is a little convex above, then sloping inward towards the anterior end
with a slight convex curve, then with a slight contraction near the anterior
end itself which appears a little produced, bulging by the sculptured siphonal
fasciole which partly encircles it. The main surface of the body whorl below
the shoulder is smooth and polished except for the nearly straight growth lines
and on closer examination, fine, wavy, spiral threads may be seen which
increase in strength below to form, stronger visible spiral threads around the
anterior end. The outer lip is sharp, nearly straight except for the curve
backward at the shoulder into the relatively wide, shallow, anal sinus. The
siphonal canal notch is wide, shallow,
forming a slightly developed bulging fasciole.
Length 53,2 mm., diameter 31,8. Gueva de Angostura, Rio
Santiago. Holotype USNM 643926
Length 40mm.(Base broken off),
diameter 31 mm. Telembi,
Rio Cayapas. Paratype USNM 643927
Angostura fm.,
Cueva de Angostura, Rio Santiago, Ecuador.
Late Miocene
Il Conus riosantiagensis può essere messo in relazione con
il Conus molis.
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Conus riosantiagensis Holotype USNM 643926 mm. 53,2 x 31,8 |
Conus cf. riosantiagensis (3) |
Bibliografia Consultata
·
(1) - Olsson, A. A.,
1964. Neogene Mollusks from
Northwestern Ecuador
·
(3)
- Johnny Alberto, Villacrés Sanchez (1990) “Estudio estratigrafico de la
Formacion Angostura en los cortes del Cerro La Mona y el Rio Cascol, Perovincia
de Manabi”, Tesi de grado Previo a la Obtenicion del Titulo de Ingeniero en
Geologia