Conus
demiurgus (Dall, 1896)
Diagnosis (1):
"Shell
large, elongate, with a large, somewhat bulbous nucleus, and about 10 subsequent
whorls ; spire low, in the young nearly flat, with a distinct but not channeled
suture; shoulder of the whorl angular, the space between the sutures flattish
or feebly excavated, sculptured with obvious lines of growth , crossed by few
faint, obsolete spiral traces ; sides of the whorl smooth, except for obsolete
spiral lines, rather wide and irregularly spaced; in the anterior third they
are stronger, but even there not very marked ; some specimens seem to indicate
a faded color pattern of continuous, narrow spiral lines, rather evenly and
uniformly spaced; aperture narrow, of equal width or nearly so; the anal notch
moderately deep, the pillar straight, with a narrow callous part not showing any
ridge or plait." (Dall, 1896)
Dimensions of holotype:
height 65.0 mm, diameter 35.0 mm.
Holotype: USNM 113920.
Type locality:
USGS 2213, one mile below Bailey's Ferry , Chipola River, Calhoun County, Florida
(=TU 457).
Occurrence: Chipola Formation, Florida; late lower Miocene.
Figured specimens:
Fig. 3, USNM
220095; height 52.5 mm, diameter 27.9 mm; locality TU 825.
Fig. 4, USNM 220096;
height 7.0 mm, diameter 3.2 mm ; locality TU 825.
Fig. 5, USNM 220097;
height 41.4 mm, diameter 22.5 mm; locality TU 548.
Other
occurrences: TU locality nos.457, 458 , 459, 546,547,554,555, 817a, 818, 819,
820b, 821 , 822, 824, 826, 827, 830, 950, 951 , 998, 999, 1050, 1052.
Discussion: The most
outstanding characteristic of C. demiurgus is its bulbous nucleus tipped with an erect, pointed
calcarella, more reminiscent of the family Volutidae than Conidae. This feature
is observed on only the very young (see pl. 1, fig. 4) and is abraded long
before reaching adulthood with only a round knob-like nucleus of about two whorls
remaining.
C. demiurgus
is
well represented throughout the Chipola Formation, but it is not considered t o
be abundant at any one locality. About 25% of the 50 specimens examined were taken from Ten Mile Creek localities, the
remainder evenly divided between the Chipola River and Farley Creek. Regardless
of locality this species shows only a minor degree of variability. Many of those
taken from certain river localities (TU 459
in particular)
retain traces of their original color pattern. This species fluoresces well and
shows a brilliant pattern with the aid of ultraviolet light
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Conus demiurgus
USNM 220095 mm. 52,5 x 27,9 |
Conus demiurgus
USNM 220097 mm. 41,4
x 22,5
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Bibliografia
Consultata
·
(1) - Hoerle, S. E.,
1976. The
Genus Conus (Mollusca: Gastropoda) from the Alum Bluff Group of
Northwestern Florida. Tulane Studies in Geology and Paleontology, 12 (1 )
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