Conus
waltonensis (Aldrich,
1903)
Shell medium in size, substance
rather thin ; spire elevated, with nine whorls, including the apex, which is
rather sharp, profile of spire slightly broken by a shoulder just above the suture
on each whorl, the suture impressed, each whorl of the spire concave, and
marked by numerous curved lines; periphery sharp; body whorl below the keel in
some specimens over one-half smooth, then below this bearing two or three
spirals of evenly-spaced nodules without any grooves between, gradually
changing to rows of nodules on bands between grooves, which are eight or ten in
number, the nodules fading away as the canal is reached, but in the type
specimen the nodules are present over the whole of the smooth part wilhout,
however, any grooves between. Anal notch rather deep, and marking the spire
with its former positions; outer lip thin, pillar lip straight with a very
slight twist; aperture straight above, widening near the base (1).
Length 20 mm., max.
diameter 12 mm.
Locality : Shoal Creek, Walt on
county, Florida.
Remarks : This shell bears a close
resemblance to Conus puncticulatus Hwass, and is doubtless an ancestral
form, thus adding another link to the chain of evidence of a connection between
the Atlantic and Pacific Oceans during Tertiary times (1).
This species has been in my
possession for many years and until lately was not known to me from any other
locality, but on looking over some specimens of fossils from the Number 2 well
of the Mobile Oil Co., bored near Mobile, Alabama, I found two or three specimens
of it, and from its position over three hundred feet above the Oak Grove (Fla.)
horizon in this well, it would seem to indicate that this deposit on Shoal
Civek is much younger than the Oak Grove beds. The assignment of these beds
to the Oligocene must, in the writer's opinion, be better substantiated than at
present. There are so few species common to the " Chipola " of Dall
and the Vicksburg formation, it would seem better to confine the use of the
term " Oligocene " to the latter, which is in accordance with
Conrad's original diagnosis, and put the Chipola, Shoal Creek and Chattahoochie
beds into one formation, calling them all Miocene, and if this should
eventually be done, then this formation should bear the name its discoverer, D.
W. Langdon, Jr., gave it of " Chattahoochie" (1).
D. G. Harris figures a Conus
puncticulatus Hwass from the Galveston deep well. It is probably the same
species as the one herein described. The pustules on the living shell appear to
be in the grooves while on the fossil form they are between them (1).
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Conus waltonensis (1)
mm. 20 x 12 |
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Conus waltonensis
Shoal
River Fm. Walton County mm. 21,3 x 13,3 [AZFC 552-01] |
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Conus
puncticulatus Lectotype
MHNG 1107/40 mm. 27 x 17 Colon
- Panama
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Conus
waltonensis anodosus (Gardner, 1937)
Shell of moderate size, of rather
heavy texture and inclined to be stout; relative height of spire ranging as in C.
waltonensis s. s. from less than one-fifth to onethird of the altitude of
the entire shell and the apical angle from approximately 90° to 120°. Whorls 9
or 10 in the adult, closely embracing the suture line, falling a little in
front of the periphery of the.preceding volution. Nucleus, small, smooth,
erect, its two or three component whorls relatively high and flattened
laterally (2).
Axial sculpture of conch
restricted to incrementals, which are strongest upon the shoulders of the
whorls of the spires. Spiral sculpture confined to the anterior half of the
body, 6 to 10 fillets or ridges separated by narrower channels usually
developed, exclusive of the half dozen crowded lirae upon the anterior canal.
Sutures strongly impressed. Aperture rather wide, the margins subparallel.
Outer lip deeply emarginate at the shoulder for the protrusion of the posterior
siphon. Labrum very thin and parallel to the inner lip. Aperture slightly expanded
at the anterior canal, which is broadly and very feebly emarginate (2).
Dimensions: Maximum height,
20.0±millimeters; altitude of spire, 3.5± millimeters; maximum diameter, 12.0
millimeters.
Holotype: U. S. Nat. Mus. No.
351122.
Type locality: No. 3856, 5 to 6
miles west-northwest of Mossyhead, Walton County, Fla.
The subspecies differs most
radically from C. waltonensis s. s. in the nondevelopment of spiral rows
of pustules upon the body whorl. In some specimens a few rows are present on
the medial portion near the aperture, but commonly they are absent altogether. Transitional
forms are less abundant than might be expected in two races, both so
prolific within the same area. The subspecies runs a little larger possibly
than the species in the strict sense, although the relation is apparently not
that of young and adult, since young forms occur with no trace of a nodose
sculpture developed upon them, whereas adults, such as Mr. Aldrich's type,
occur with nodules from the periphery of the ultima to the anterior canal. The
thinness of the outer lip seems to have rendered the form peculiarly
susceptible to injury, and repairs have been made on a large proportion of the
shells collected (2).
Occurrence:
Shoal River formation, localities 3856pr, 2645P, 3731a, 5080C, 5184a, 5195P,
3742a (2).
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Conus waltonensis anodosus (2)
Plate XLIII, figure 15 mm. 20 x 12 |
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Conus waltonensis anodosus (1)
mm. 22 |
Conus
waltonensis blountensis (Mansfield, 1935)
Shell small, ruther stout with 7 or
8 whorls in all. Spire turrited, evenly and broadly conic and constitutes about
one-fourth of shell length. Spire whorls carinated at the lower shoulder and
depressed medially. Body whorl broad above and narrow below and sculptured,
from the upper third to the siphonal fascicle, with about 10 rather wide spiral
bands, which arc ornamented with a few granules. Siphonal fascicle weakly
elevated and marked
with 5 or 6 closely spaced and
narrow spiral bands (3).
The holotype
(U.S.N.M.Cat.No.373119) measures: Length, 17.2 mm.; greatest diameter, 9.2 mm.;
Length of spire, 5 mm.
Conus waltonensis blountensis, n. subsp. differs from Conus waltonensis Aldrich, a species
from the Shoal River formation in having a relatively higher and more evenly
conic spire; broader body whorl above and more constricted below; a
stronger carina at the shoulder of the body whorl; and in the absence of
granules on the upper third of the body whorl (3).
Occurrence:
Upper middle Miocene, Area zone. Station 12046, Vaughan Creek, upper locality,
Walton County, Fla. (type locality). Known only from the type locality
(3).
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Conus waltonensis bloutensis (3)
Plate 1, figure 9 mm. 17,2 x 9,2 |
Bibliografia
Consultata
·
(1) - Aldrich, T. H.,
1903. A
new Conus from the Tertiary of Florida. The Nautilus: A Quarterly Devoted
to Malacology, 16 (11 ): 131 -132
- (2) - THE MOLLUSCAN
FAUNA OF THE ALUM BLUFF GROUP OF FLORIDA BY JULIA GARDNER
·
(3) -
Mansfield, W. C., 1935. New Miocene Gastropods and Scaphopods from Alaqua Creek
Valley, Florida. State of Florida, Department of Conservation, Geological
Bulletin, 12: 1 -64
·