Conus colossus (Eames,
1952)
Material. Rakki Nala section: White Marl Band (local zone 1 1 ) (FB. F. 1964, the holotype, Reg. No. G. 68398).
Description.
Specimen poorly preserved
but extremely large, conic in shape, with an almost flat, slightly convex
spire; anterior portion of body whorl missing, but flanks of that part which
remains stiffly subcylindrical. The number of spire whorls cannot be
determined. Width of spire is 168 mm., and width of body whorl above the
shoulder near the aperture 68 mm. Spire whorls showing on the mould a slightly
convex upper surface except on the later part of the body whorl where the inner
part is more convex and the outer part gently concave. This latter feature, as
well as the considerably sharper shoulder at this point, are probably due to
distortion. Shoulder near beginning of body whorl rounded, but sharper in the
middle and later stages. The slight upturning of the sutural region of the body
whorl near the aperture also seems to be due to the same distortion. Aperture
apparently almost parallel-sided. The broken basal section shows that there
were no columellar folds.
Dimensions.
Holotype: height
(incomplete) 81,0 mm.; width (apertural view) 168,0 mm.; width (at right angles
to apertural view) 114,0 mm.
Remarks.
The specimen is a mould. In
spite of the poor preservation the species merits naming since it is very
considerably larger than any Eocene form with which the writer is acquainted. Although
represented in these collections by only one specimen, it was represented in
the Burmah Oil Company’s collections of fossils, lost during the evacuation of
Burma in 1942, from similar horizons in the Khirthar of Western Pakistan.
Conus planus von Schauroth
(B 1865 , p. 229, PL 25, fig. 1), from the Lower Tertiary of Italy, is somewhat
similar in form, but has an absolutely flat spire, less parallel flanks to the
body whorl, and is considerably smaller.
Conus pyramidalis Munster as
figured by Schafhautl (B 1863 , p. 2 1 1 , PI. 52, fig. 7), from the Eocene of
Kressenberg, is considerably smaller and its flanks are less parallel. The
rather high and stiffly conic outline, almost flat spire, and exceedingly large
size are characters which, taken together, are typical of the Pakistan form.
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Conus colossusFigures 140 a, b, plate 6 Eocene |
Bibliografia
·
(1)
- Eames, F. A., 1952. A Contribution to the Study of the Eocene in Western
Pakistan and Western India. Philosophical Transactions of the Royal
Society of London, ser. B. vol. 236