THE NAUTILUS 121(3):105-130, 2007
Pare 105
The Epitoniidae (Gastropoda: Ptenoglossa) from die lower Alum
Bluff Group (lower to middle Mioceue) of Florida, with
descriptious of niue new species
Gan W. Schmelz
5575 Dogwood \\'a\
Naples, FL 34116 USA
Roger W. Porlell
Florkla Musouiii ol Xatuial Iliston'
University ot Floritla
P.O. Box 117S0()
Gainesville, FL .3261 ] -7S00 USA
portelltS'llnmh, uil.edu
AB.srKAc;r
A comprehensive studx of the iamiK Epitoniidae that e.xists in
tlie lower to middle Miocene portion of the Alum Bluff Group
of Florida (USA) was conducted. A total of 14 species was
examined. Of these, 12 are considered valid members of the
famih' Epitoniidae. They include three previously described
species, Atnaca gardneirie, Ciraotrema cirritiim, and Epitoiiiiim
lirginiiie. plus nine new species. Seven of the new species were
collected from the Chipola Formation and tvvo from the Shoal
Ri\'er Formation. One new species is assigned to the genus
Cirsotreina, two are assigned to the genus Opalia. and six are
assigned to tlie genus Epitoniiim.
Cirsotrema previously reported from the Chipola Formation
as Cirsotrema dalli, a Pleistocene to Recent species, has been
described as a new species. Epitoniuin alaqitacnse reported
from the upper Miocene Choctawhatchee Formation (upper
-Alum Bluff Group) and questionably placed in the Shoal River
Formation fauna b\' Gardner ( 1947) is no longer recognized as
a Shoal Ri\er Formation species and Gcgania acutissima has
been placed with the Architectonica-\ike members of the family
Madiildidae.
Additional Kcijwords: Miocene, Chipola Formation, Shoal
River Formation, Cirsotrema. Opalia, Epitoniuin, Chipola
Ri\er, Tenmile Creek, Farlev Creek
INTRODUCTION
The family Epitoniidae has an extensive history wath rep-
resentatives dating back to the early Mesozoic. According
to Clench and Turner (1950), the group appears to have
reached its peak of diversity during the Eocene and Mi-
ocene epochs. In Florida (USA), members of the familv
are well represented in early Miocene deposits and, to a
lesser extent, in middle Miocene deposits of the Alum
Bluff Group.
The -Alum Bluff Group consists of five named strati-
graphic units (Figure 1). From oldest to youngest these
units are die Chipola Formation, Oak Grove Sand, Shoal
Author for correspondence
River, Choctawhatchee, and [ackson Bluff formations
(Huddlestun, 19S4). All of the Ahnn Bluff strata occur in
outcrops in the western portion of the Florida panhandle
(Figure 2). Tlie lower Miocene Chipola Formation was
deposited approximately 18 mya (Jones et al., 199.3) and
outcrops along Tenmile, Farley, and Fourmile creeks,
and the Chipola, Yellow, Choctawhatchee, and Apalachi-
cola rivers. To date, most Chipola Formation specimens
have been collected from Tenmile, Farlev, and F"om"mile
creeks, and tlie Chipola River. Collections ot iossil speci-
mens irom the Oak Grove Sand along the Yellow River
and the Chipola Formation along the Apalachicola River
are limited, given that these locations hpicallv can only
be accessed dining veiy low water levels. According to
Yokes (1989), Tenmile Creek, Farley Creek, and Chipola
River complex alone encompasses over 7.5 miles (-12
km) of Chipola Formation exposures. Tlie middle Mi-
ocene Shoal River Formation was deposited approxi-
mately 12 mya (Jones et al., 1993). All known Slioal River
Formation outcrops are west of the Chipola Formation
exposures with most of the collecting areas situated along
the Shoal River in Walton Counts'. Ovemews of the ge-
ologv', stratigraphv, and paleontologx' ot the Chipola and
Shoal River formations can be found, respectively, in
Yokes (1989) and Portell et al. (2006).
Gardner (1947), as part oi her monographic treatment
of the moUuscan fauna of the Alum Bluff Ciioup, chs-
cussed three species belonging to the hmiily Epitoniidae.
These species were Epitoniuin iSpiniscala) virginiae
(Mauiy, 1910), Epitoniuin [Clcitliiiis) alaquaensc (Mans-
field, 19.35), and Gegania acutissima (Dall, 1892). How-
ever, only two of these taxa are herein consiilered to
belong to the family Epitoniidae. Epitoniuin cirginiac
was collected from a Chipola Formation site along the
east bank of the Apalachicola River. It was described by
Maury (1910) from a single, extremely small (3.7 mm
maximum heiglit x 1.5 mm maximum width) specimen
that was part of the Cornell UniversitA-Collection (now
deposited at the Paleontological Research Institution).
Epitoniuin (ddijuaense, recorded by Mansfield (1935)
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