The Epitoniidae (Gastropoda: Ptenoglossa) from the lower Alum Bluff Group (lower to middle Miocene) of Florida, with descriptions of nine new species

2007·11.6 MB·English

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 Roger W. Porlell
5575 Dogwood \\'a\ Florkla Musouiii ol Xatuial Iliston'
Naples, FL 34116 USA University ot Floritla
P.O. Box 117S0()
Gainesville, FL .3261 ]-7S00 USA
portelltS'llnmh,uil.edu
AB.srKAc;r
River, Choctawhatchee, and [ackson Bluff formations
A comprehensive studx of the iamiK Epitoniidae that e.xists in (Huddlestun, 19S4). Allofthe Ahnn Bluffstrataoccurin
tlie lowerto middle Miocene portion ofthe Alum BluffGroup outcrops inthewesternportion ofthe Floridapanhandle
of Florida (USA) was conducted. A total of 14 species was (Figure 2). Tlie lower Miocene Chipola Formation was
feaxmaimhi'neEdp.itOonfiitdhaees.e,T1h2eyareinccloundseidethrreedevaplriedvimoeusmlbyerdesscorfibtehed deposited approximately 18 mya (Jones et al., 199.3) and
outcrops along Tenmile, Farley, and Fourmile creeks,
species,Atnacagardneirie,Ciraotremacirritiim,andEpitoiiiiim
lirginiiie. plusninenewspecies. Sevenofthenewspecieswere andthe Chipola, Yellow, Choctawhatchee, andApalachi-
collected from the Chipola Formation and tvvo from the Shoal cola rivers. To date, most Chipola Formation specimens
Ri\'er Formation. One new species is assigned to the genus have been collected from Tenmile, Farlev, and F"om"mile
Cirsotreina, two are assigned to the genus Opalia. and six are creeks, andtlie Chipola River. Collections ot iossil speci-
assigned to tlie genus Epitoniiim. mens irom the Oak Grove Sand along the Yellow River
Cirsotrema previouslyreportedfrom the Chipola Formation and the Chipola Formation along the Apalachicola River
as Cirsotrema dalli, a Pleistocene to Recent species, has been are limited, given that these locations hpicallv can only
described as a new species. Epitoniuin alaqitacnse reported be accessed dining veiy low water levels. According to
from the upper Miocene Choctawhatchee Formation (upper
Yokes (1989), Tenmile Creek, FarleyCreek, and Chipola
-Alum BluffGroup) and questionablyplaced in the Shoal River
River complex alone encompasses over 7.5 miles (-12
aFoSrhmoaatlioRni\fearunFaorb\m'atGiaorndnseprec(i1e9s47a)ndisGncoglaonnigaeracruetciosgsniimzaedhaass km) of Chipola Formation exposures. Tlie middle Mi-
beenplacedwiththeArchitectonica-\ikemembersofthefamily ocene Shoal River Formation was deposited approxi-
Madiildidae. mately 12 mya (Jones etal., 1993). All known Slioal River
Formation outcrops are west of the Chipola Formation
Additional Kcijwords: Miocene, Chipola Formation, Shoal
exposureswithmostofthecollectingareas situatedalong
River Formation, Cirsotrema. Opalia, Epitoniuin, Chipola
Ri\er, Tenmile Creek, Farlev Creek the Shoal River in Walton Counts'. Ovemews ofthe ge-
ologv', stratigraphv, and paleontologx' ot the Chipola and
Shoal River formations can be found, respectively, in
INTRODUCTION Yokes (1989) and Portell et al. (2006).
Gardner (1947), as part oi her monographic treatment
The familyEpitoniidae has an extensivehistorywath rep- of the moUuscan fauna of the Alum Bluff Ciioup, chs-
resentatives datingbacktothe early Mesozoic. According cussed three species belongingtothe hmiily Epitoniidae.
to Clench and Turner (1950), the group appears to have These species were Epitoniuin iSpiniscala) virginiae
reached its peak ofdiversity during the Eocene and Mi- (Mauiy, 1910), Epitoniuin [Clcitliiiis) alaquaensc (Mans-
ocene epochs. In Florida (USA), members ofthe familv field, 19.35), and Gegania acutissima (Dall, 1892). How-
are well represented in early Miocene deposits and, to a ever, only two of these taxa are herein consiilered to
lesser extent, in middle Miocene deposits of the Alum belong to the family Epitoniidae. Epitoniuin cirginiac
Bluff Group. was collected from a Chipola Formation site along the
The -Alum Bluff Group consists of five named strati- east bank ofthe Apalachicola River. It was describedmbmy
gunriatpshiacreundiitesC(hFiipgoulraeF1o)r.mFartioomn,olOdaesktGtrooyvoeunSgaends,t Sthhoeasle mMaauxriymu(m19h1e0i)gliftroxm1a.5simngmle,maexxtirmeumemlywisdmtahl)ls(p3e.7cimen
that was part of the Cornell UniversitA- Collection (now
deposited at the Paleontological Research Institution).
Author for correspondence Epitoniuin (ddijuaense, recorded by Mansfield (1935)
.
Paee lOfi THE NAUTILUS, Vol. 121, No.
Cooke(1945) Huddlestun(1984) Vokes(1989) Scott Carteretal (2003) ThisPaper
(2001)
LLOZUU DUPLINMARL JACKSFOMNBLUFF JACKSFOMNBLUFF JACKSFOMNBLUFF JACKSFOMNBLUFF
gQ- Can{cEeclplharoiraazaonndes) Can{cEeclplhaoriraazaonndes) Can[cEeclplharoiraazaonndes) (Cance/Zar/azone) Can(cEeclplhaonraazaonndes)
CHOCTAWHATCHEE CHOCTAWHATCHEE
Arearzuobnieziniana {AreFaMzone) R(EADreaBAzYonFe)M QLLI R{EADreaBAzYonFe)M (4rcFaMzone)
Z mX
LU o
<X CDL
O
Vo/d/awaltonensis (Vo/Udp(paezrone) YELLOWRIVERFM UOz3- 8O<T YELLOWRIVERFM. OuLc3_Lr
ir (Yo/d/azone) a. {Yoldiazone) —I SHOALRIVERFM.
LZLOJUJ n< Oqo: C3D "Ca(rIdniculmudbeesds'
O r Middle ofGardner(1926).
U-J oT-1 (Mainshellbed) u=—.)1 SHOALRIVERFM Yoldiazoanneds,Glayncdymens
Glycymens in CO WhitesCreekMember)
waltonensis SHOALRIVERFM
zone WHITESCREEK _<l
MEMBER WHITESCREEKBEDS
y
Cardiumtaphnum OAKGROVESAND OAKGROVEFM / OAKGROVESAND OAKGROVESAND
zone
CHIPOLAFM 1 CHIPOLAFM / CHIPOLAFM. CHIPOLAFM J CHIPOLAFM
^^^H ^^^^1
Figure 1. Aliiiii Bluff Group stratie;raphic noinenclatiiial lii.ston and conelation (in part). Modified from Portell et al. (2006).
from theArea zone of the Choctawhatchee Formation, is familv Epitouiidae because she fi-lt tliat its inoi|iliologi-
late Miocene (Huddlestnn, 1984). When Gardner (1947) cal characteristics more closely coincided with the sub-
collected a shell fragment similar to Mansfield's shell at order Ptenoglossa. Gardner's generic assignment of Ge-
a Shoal River site she included it as part of the lower gania was based upon the shell similaritx* to Gegania
Alum Blufi Group as defined by Cooke (1945). The col- pinquis Jeffreys, 1884, a species collected during the
lecti\e exddence now suggests that E. alaquacnse should Porcupine Expedition oft Cape Mondego, Portugal.
not be listed as part ofthe faunaofthe lowerAlum Bluff However, the genus Gegania has since been assigned to
Group (see Figure 1). The reasons for this are twofold. AreJuteetonica-\\ke members of the familv Mathildidae
First, an extensive examination of the Chipola and Shoal (Vaught, 1989).
Riverformation fossils in the Florida Museum ofNatural In addition to the three species of Epitoniidae listed
History (including Tulane University and Florida Geo- for the Alum Bluff Group, Garchier (1947: 575) reported
logical Survey collections), Paleontological Research In- shell fragments belonging to "at least a dozen" species.
stitution, Smithsonian's National Museum of Natural Gardner stated that most of the specimens were so im-
History, American Museum of Natural History, The perfectly presened that onl)' subgeneric determinations
Academy of Natural Sciences, Alabama Geological Sur- could be made. Four of the unidentified epitoniids came
vey, and private collections during this study did not from the Aklrich Collection (housed at Johns Hopkins
uncoverasingle specimen that could be referred to as E. University) and the remaining species were from (iard-
alaquacnse. Second, Gardner (1947: 577) stated that she ner's collection. Eleven ofthe fragments were obtiiined
collected her shell fragment from "a Iiorizon sliehtlv from Slioal River Formation localities and two were col-
higher than the tyjiical Shoal River fonriation." Based lected from Chipola Formation sites. Gardner placed
upon this remark and that no additional specimens simi- eleven of the fragments in the genus Epitoniuni, one in
lar to E. alaquacnse were ever found in the above- the genus Scalina, and one in the genus Gegania. Six
mentionedcollections, it seems fairto assume that Gard- were placed in the subgenus Hi/aloseala, two in Spini.s-
ner'sspecimen belongedtostratayoungerthan the Shoal cala. three in Cinctiscala, and one in Nodiseala.
River Formation; most probably to the ujijier Miocene fl is apparent from Gardner's (1947) discussion on the
Choctawhatchee Formatioi F,piloniidae of the Alum Bluff Group that future work
i
Dall (1S92) described Tnlia acnlissiina and placed it in I'einaiiicd to l)e done on the family. Since her publica-
the family Mathildidae. Gardner (1947) replaced the ge- tion, three additional species of Epitoniidae have been
nus Tulxi with Ceciania and tentati\-elv assigned it to the re]iort('d b'om the Cln^iola Formation. These are Cir-
G. ^\". Schmelz and R. W. Portell 2007 Page 107
N
A
i
Okaloosa
Alum Bluff
Group
Figure 2. Map ot Florida showing counties wath Ainiii BluFf Group setliinents found at or near the surface.
sotrema dalli Rehder, 1945; Scalinn gardncrac (Olsson, (198.3a; 1983b; 1993), Weil et al. (1999), and others, cur-
1967); and Cinotrema cirritniii Duerr, 2004. Cirsotreina rent classification ofthe Epitoniidae is based upon shell
dalli is an extant species reported to have undergone characteristics. For this study, moq:)hological features
little moi"phologicalchange sincethe earlv Miocene (Ols- such as shell size (height and width), number and shape
son, 1967). Scalina gnrdnerae was described bv Olsson ofthe nuclear whnrls, number and shape of teleoconch
(1967) from a single large specimen collected from Mc- whorls, number amiplacement ofthe costae on the body
Clellan's Farm in Calhoun Count\s Florida. It is a fairh- whorl, presence orabsenceof\arices, tvpe of sculpturing
common species, and since its discover)', it has been on the bodv whorls, shape ot the aperture, shape and
found at numerous Chipola Formation sites bv the au- thickness ofthe outer lip, depth ofthe sutin'e, presence
thors and otlier investigators. Cirsotrenm cinitiim is a ofpunctae, and the spire angle were used to help differ-
much less common species collected at a few sites along entiate species. Spire angles were measured from pho-
Tenmile and Farlev creeks and the Chipola River (Du- tographs. A vertical line was di-a\\ai through the a.xis of
err, 2004). the sliell and a protractor was used to determine the
Scattered among the material in museums andprivate angle between the margins of the bodv whorls on both
collections are a large number of epitoniids from the sides ofthe shell.
Cliipola and Shoal River formations ofFlorida that have Additionally, in ordei' to ascertain whether or not the
been amassed o\er the last fift\-\ears. Since manv ofthe Chipola Formation species ofCinotrcma is the same as
recentK" collected specimens are in excellent shape, we the Recent Cirsotrcma dalli, we closely examined the
ha\e undertaken the task of identifving and describing \-arices on iiuth forms. As notedbvWeil et al. (1999) and
the new species and providing better descriptions and others, the presence or absence ofvarices can be a key
updated taxonomic placements of existing ones. As wll diagnostic feature for some species of Epitonium. We
be evidencedin thispaper, manvoftheseepitoniids have believe that the structural configirration and the number
shell structures that are similar to those of extant and of varices that appear within a specific generic group,
fossil species from Florida, the Caribbean, western Eu- such as in certain Epitcuium, will change over geologic
rope, and the eastern Pacific. time and that this moq^liological difference between the
According to Clench and Turner (19.51). DuShane Recent and fossil forms is significant enough to justify
(1979), Kilbum (1985), Xakavama (200.3j, Robertson naming tlie fossil form as a separate species. In part, this
Page 108 THE NAUTILUS, Vol. 121, No. 3
decision to use the changes obsei'ved in vailx count as a erature came from publications dealingwith the descrip-
diagnostic feature at the species level is based upon the tions of Recent and fossil species collected from the
precedence of using the number, shape, and configura- United States, Central and SouthAmerica,the northwest
tion ofvarices as a method ot identiRing different spe- Atlantic, Eiu'opean continent, and the eastern Pacific.
cies and genera in the family Muricidae. This technique Institutional abbreviations used herein are: USNM:
hasbeenusedbroadlybymuricidgastropodinvestigators National Museum of Natural History, Smithsonian Insti-
(Herbert, 2005, and references therein). tution, Washington, DC; UF: Florida Museum of Natu-
Besides examining the varices on Cirsotrema dalli, we ral Histon- (FLMNH), UniversityofFk)rida, Gainesville;
also abraded the external portion ofan uncataloguetl Re- TU: Tulane University, (formerly housed in New Or-
cent shell in order to compare its underlying sculpture leans, Louisiana and now housed at the FLMNH); PRI:
with that of its fossil counteipart. Paleontological Research Institution, Ithaca, New York;
Even though many of the epitoniids examined are in ANSP: The Academv of Natural Sciences, Philadelphia,
excellent shape, the task ofclassifying them and placing Pennsylvania; and BMSM: The Bailey-Matthews Shell
them into their appropriate generic and subgeneric Museum, Sanibel Island, Florida. Because of privacy
groupings was challenging. This is, in part, because there rights of landowners, specific locality data for specimens
is ven' little natural histon" information on Recent spe- described below are not given. However, specific locality
cies thatprovide insight into howthese animals gi'ow and information is available to qualified researchers upon
how their growth is impacted bv environmental condi- written request to [email protected].
tions. Subsequently, we have relied heavily upon the
combined works of numerous past investigators to help SYSTEMATICS
us with this decision making process. These researchers
included, but were not limited to: Brunet (1995), de SuperfamiK |antliinoidea Lamarck, 1812
Bouiy (1909), Clench and Turner (1950; 1951; 1952), Family Epitoniidae Bern', 1910
DuShane (1979; 19SS), Gardner (1947), Kilburn (1985), Genus Aiiuiea H. and A. Adams, 1853
Nakayama (2003), Robertson (1983a; 1983b; 1993), Weil Type Species: bv suliseijuent designation, Scalaria
et al.'(1999), and Woodring (1959). ina^nijiva Sowerby, 1844.
At the generic and subgeneric levels of classification
manyinvestigators have widely divergent opinions about Subgenus Scalina Conrad, 1865
in which group a specific epitoniid should be placed. AAiinnaaeeaa ggaarrddnneerac (Olsson, 1967)
Accordingto Clench andTurner 1950), de Bouiy's work (Figures 3-9)
(
on Epitoniidae left behind a long list of generic and Description: Slicll large, tniiiculatc; protoconch miss-
subgeneric names with only the types available for diag- ing; nine or ten teleoconch whorls. Spire angle 19.5°.
nostic analysis. This list includes seven generic and 19 \Vhorls convex, relati\el\' thin, with cancellate sculpture.
subgeneric names (Weil et al., 1999). It was Clench and Cancellate pattern created by foiu- spiral cords crossed
Turner's (1950) opinion that de Bouiy became confused by smaller, evenly spaced axial costae; square spaces
about the overlapping characteristics of the Epitoniidae within cancellate sculpture possess textured pattern cre-
and ratherthan tning to place tliem into existingcatego- ated by tine overlapping iLxial and spiral threads. Suture
ries, he established new genera and subgenera for them. deeply impressed. Basal cord well-defined, surface
To date, this confusion with overlapping characteiistics slightly elevated and sculpturedwith thin spiral and axial
appears to have continued with the list of generic and tlu'eads. Sculpture below basal disc lacks elcMited spiral
subgeneric extant Epitoniidae alone being expanded to cords. I'mbilicus absent.
34 and38 names, respectively(Weilet al, 1999). Forour Ilololype: USNM 645180, maxinnnn height 47.5 nun,
classification purposes we have decided to adhere, as ma.xinnun width 14.4 mm.
closelyaspossible, tothe moreconservative phylogenetic
scheme followed by Clench and Turner (1950) rather Type Locality: McCl Farm, Calhoun Countv,
than the more recentlyexpandedversion usedbyWeil et Florida.
al.W(i1t9h99)fosasinlds,Npalkaacyeammenat(2o0f04c)e.rtain epitoniids into ap- OmitlheeCrrMeaetke0r4ia(lCAE0.2v0a)mi(n=edT:ulanUeFUn1i1v7e0r4s5i,ty1lsohceallli.tyTeTnU-
propriate generic and subgeneric groups has been ham-
951), Clarks\ille Quadrangle USGS 7.5' Series (1945),
pered byerosion (taphonomic degradation). This process Calhoun County, Florida, Chipola Formation; UF
removes surface sculpturing present on living specimens
and exposes subsurface characteristics that are remark- c1e1d7i0n8g7;,U1Fs9h1e4ll5,9,lo1c6alsihteyllsa,ndTenfmorimlaetiCorneeska0m3e(aCsA0p1r7e)-
ably different. In this paper, an example of the impact (= Tulane University locality' TU 546), Clarksville Quad-
erosion has on the external features of a shell is illus- rangle USGS 7.5' Series (1945), Calhoun County,
trated with the new species Epifoniiim coinvaiac.
We Florida, Chipohi Formation.
have tried to sui"vey all the pertinent descriptions
and illustrations ol both fossil and Recent epitoniids. For Dislrihiition: Anun-ii <^iirdiicrac is a fairly conniion
taxonomic comparison pmposes tlie most significant lit- ('liipcila i''()niiali()ii spciics. Il is abundant at several col-
G. W. Schiiielz and R. W. Portcll. 2007 Page 109
Figures 3-9. Attuica gtirdncrac (OLssoii, 1967). 3-4. Apcrtural and aliapcrtural \"ic\\s nl liolot\.pe USNM 645180ongiiiall\ named
ScalinagardneraeOlsson, 1967. Sinceitsoriginaldescriptionthespecimenhasdegraded; maximumheight47.5mm,maximumwidtli
14.4 mm. 5-8. Apertural, lateral, abapertural, andbasalviews ofUF 117045showaiforcomparison toholot\pe (USNM 6451S0) and
otherChipolaand Shoal River formation epitoniid species; maximum height 17.85 mm. maximum width 5,4 mm. 9. Magnified\ie\v
ofsculpture ofteleoconch ofUF 117045. Scale bar = 0.6 mm.
lection sites along Tenmile Creek but is less abimdant (lifiicult to tell what the sculpturing was hke in the vi-
along Farley Creek and the Chipola River. Thus far, cinitv'ol the basal cord. Subsequent specimens, however,
diere are no reports ofit havingbeen collected alongdie have revealed that the sculpturing above and below the
Yellow or the Apalachicola rivers. basal cord is different in S. gardnerae (Figures 5, 8).
Et\TnoIog\-: Named for Julia A. Gardner, a pioneer Clench and Turner (1950), Weil et at. (1999), and
researcher on Chipola Formation molhisks. Nakayama (2003) have allplacedepitoniidswiththeshell
sculpture described by Olsson (1967) for Scalina gard-
Discussion: Gardner (1948) reported an epitoniid nerae into the genus Amaea. We are in complete agree-
fragment from the Chipola Formation which she as- ment with this placement and have assignetl Olsson's
signed to the genus Scalina. Olsson (1967) later de- epitoniid to that genus.
scribed diis species as Scalina gardnerae. A more thor- Weiletal. (1999) hasidentified eightsubgenericforms
ough analysis of additional specimens of S. gardnerae ofthe genus Amaea. These subgenera are distinguished
now indicates that it should be placed in the genus from one another by the t)pes of sculpture that appear
Amaea. DuShane (1988) noted that members ofthe ge- above and below the basal cord. Nakayama (2003) in his
nusAnmea are largerthan anvk-nown Scalina and have a review ofnorthwest Pacific epitoniids retained six of the
less distinct basal cord. In addition, Du.Shane observed subgenera hsted by Weil et al. (1999). Among the six
that in the genus Amaea, the sculpture above and below subgenera hsted for the genus Amaea by Nakayama
the basal cord is different. Unfortunatelv. the poor con- (2003), the present authors have assigned the Chipola
dition ofthe t\pe specimen describedbvOlsson makes it Formation species to the subgenus Scalina. According to
Page 110 THE NAUTILUS, Vol. 121, No. 3
Nakayama (2003) andWeil et al. (1999) meniber.s ofthis them, possess numerous distinct spiral threads. Thin ver-
subgenus possess convex bodv whorls with a cancellate tical threads intersect spiral threads, creating faint can-
sculpture oi spiral cords and a.\ial ribs. cellate pattern. \'arices formed from accretion of foliated
Representatives of the genus Amaea have been re- costae; varices poorly developed and onlv slightly el-
ported from a number of other fossil locations. These evated. Apical end ofcostae v\dth pointed nodes. Surface
include Scala {Opalia) reticulata Martin, 1904, from the of costae pitted with obliquely arranged small holes.
Miocene Calvert Formation of Vlarvland, Amaea Three or four obliquely arranged, slightlv elevated, nar-
(Scalina) fenniniana (Dall, 1908) from the Pliocene Es- row cords traverse each costa. Oblique cords on costae
meraldas beds of Ecuador, Scala (Acrilla) wiegandi less pitted than remainder ofsurface area. Base ofeach
(Bose, 1910) from Me.\ico and the Miocene Chagres costa stem-like, attached to a broad, crenulated, basal
Formation of Panama (formerly Canal Zone), Scalina cord. Basal diskcomposite, created byalarge outerbasal
pseuclolerogi (Maury, 1925) from the Pliocene of Tiin- cord with crenulated edges; a middle circle of narrow
idad, Epitoniiiin (Fenninoscala) manabiainiin (Pilsbn' linear pits; and an inner columellar cord with a crenu-
andOlsson, 1941), andEpitonium (Femiinoscala)eleuth- lated edge. Aperture subcircular. Columella short and
erium (Pilsbiy and Olsson, 1941) from the Pliocene arched. Lip margin thickened, pitted in unworn speci-
fauna ofwestern Ecuador, Scalina hoijlae (Olsson, 1967) mens. Less eroded specimens possess a shghtly elevated
from the Pliocene Tamiami Formation of Florida, and node on the posterior outer margin of the lip.
Scalina kendacensis Jung, 1971, from the Miocene Ken-
deace Formation ofCarriacou. Amaeafenniniana, origi- Holotvpe: UF 117088, maximum height 32.9 mm,
nally described from the Recent of Baja California, is an inaxiniuni width 15.0 mm.
offshore species. It ranges from Mexico south to Pern Type Locality: Tenmile Creek 03 (CA017) (= Tulane
(Weil et al, 1999). DuShane (1988) considered E. Uni\ersit\- locality TU 546), Clarksville Quadrangle
eleutherium and S. wiegandi to be synonvmous with A. uses 7.5' Series (1945), Calhoun County, Florida,
fenniniana and suggested that S. pseuclolerogi as well as Chipola Formation.
some otlier fossil species ofAmaea may be synonymous
withA.fenniniana. Comparison ofA. gardnerae wth A. Paratypes: UF 117089, 1 shell, locality and formation
fenniniana clearly illustrates that the two species are not same as holotvpe; UF 91490, 5 shells, locaht)- and for-
synonymous. Amaeafenniniana possesses six to nine spi- mation same as holotvpe; UF 84575, 7 shells, Tenmile
ral cords ofuniform tliickness on the body whorls, while Creek01 (CA002) (= tulane UniversitylocalityTU 830),
A. gardnerae possesses four broad primaiy cords with Clarksville Quadrangle USGS 7.5' Series (1945), Cal-
finer cords in between. The costae on A. gardnerae are houn Count)', Florida, Chipola Formation; UF 95161, 1
alsoless prominentthen theyareonA.fenniniana. Com- shell, Tenmile Creek 04 (CA020) (= Tulane University
parison ofAmaea mitchelli (Dall, 1896), a Recent west- localit^• TU 951), Clarksville Quadrangle USGS 7.5' Se-
ern Atlantic species, to A. gardnerae was also made. ries (1945), Calhoun Countv, Florida, Chipola Forma-
Amaea mitchelli has 6-7primaiyspiralcords onthe liody tion; UF 85383, 1 shell, Chipola 09 (CA018) (= Tulane
whorls (four ofwhich are closelv spaced belowthe\vhorl LJniversity locality TU 547), Clarksville Quadrangle
mid-line and two to three that ai'e evenk- spaced above) USGS 7.5' Series (1945), Calhoun County, Florida,
as compared to A. gardnerae which has four evenly Chipola Formation; UF 13966, 1 shell. Chipola 03
spaced primary spiral cords. (CA005), Chipola River (exact collection site unknown),
Calhoun Countv, Florida, Chipola Formation; UF
Genus Cirsotrema Morch, 1852
94650, 1 shell, tenmile Creek 02 (CA003) (= Tulane
Type Species: Scalaria varicosa Lamarck, 1822, by Universitv locality TU 70), Altha West Quadrangle
monotypy. USGS 7.5' Series (1982), Calhoun County, Florida,
Chipola Formation; UF 84444, 1 shell, Farley Creek 03
Cirsotrema chipolannm new species (CA009) (= Tulane University locaUty TU 825), Clarks-
(Figures 10-14) ville Quadrangle USGS 7.5' Series (1945), Calhoun
Description: Shell large, turriculate, protocouch miss- Countw Florida, Chipola Formation; UF 91356, 1 shell,
ing; seven to eight teleoconch whorls. Spire angle 27°. Chipola 07 (CA015) (= Tulane University- locality/ TU
WTiorls slightly convex, strongly shouldei-ed and joined. 554), Clarksville Quadrangle USGS 7.5' Series (1945),
Priman' underlying sculpture present on telecjconch Calhoun Countv, Florida, Chipola Formation; USNM
whorls consists of slightly elevated vertical ribs. Suture 534489, 1 shell,' Tenmile Creek 01 (CA()02) (= Tulane
deep, covered by external sculpture. Seventeen to 23 University locality TU 830), Clarksville Quadrangle
sinuous, inclined, feather-like, broad costae on liodv USGS 7.5' Series (1945), Calhoun County, Florida,
whorls. Edges of foliated costae occasionally toucli tlie Chipola Formation; USNM 534490, 2 fragments, locality
preceding ones giving the shell surface a pitted appear- and formationsame as preceding; USNM 534491, 2 frag-
ance. In other instances foliated costae are slightly sepa- ments, Tenmile Creek 05 (CA021) (= Tulane University
rated from one another. When feather-like costae sepa- localit)' TU 998), Clarksville Quadrangle USGS 7.5' Se-
rate from each other, five slightly elevated spiral cords ries (1945), Calhoun Count)', Florida, Chipola Forma-
seen on body whorls. Spiial cords, and spaces between tion; USNM 534492. 1 shell, Fariey Creek 03 (CA009)
G. W. Schmelz and R. W. Poitell 2007 Paee 111
Figures 10-19. Cirosotrcma cltipolaiuim new species and C'irsDlrenin ilnlli lii lull r, 194.5 10-13. Cii'sotrriiia cliipiiJtiniim: aper-
tural, lateral, abapertural, and basal \'iews of huldhpe UF UTOiSS; maximum height 32.9 nnii, m;L\ininm width 1.5.0 mm. 14.
Magnified \ie\v ofseulpture ofteleoconch ofholohpe UF 117088. Scale bar = 2.8.5 mm. 15-18. Cirsofrcmu diilli Rehder, 194.5;
apertural.lateral,abapertural,andbasalviewsofUF2.38698; maximumheight.32.8 mm and maximumwidth 13.8mm. 19. Magnified
\iew ofsculpture ofteleoconch of UF 238698. Scale bar = 5.0 mm. UF 238698 live collected offEgmont Key, Pinellas Count)',
Florida at about 52 m depth.
Page 112 THE NAUTILUS, Vol. 121, No. 3
(= Tulane Universitylocalitx'TU 825), Clarksville Quad- identifving different species of Cirsotrema from beach
rangle USGS 7.5' Series' (1945), Calhoun County, worn specimens.
Florida, Chipola Formation; USNM 53449.3, 10 shells, Often with fossil specimens it is difficult to find shells
Tenmile Creek 03 (CA017) (= Tulane Universit)'localit)' thathavenotbeen eroded. However, asufficientnumber
TU 546 and USGS 2212 "one mile west of Bailey's of well-presei'ved Chipola Formation Cirsotrema were
Ferry"), Clarksville Quadrangle USGS 7.5' Series (1945), discovered which allowed a more detailed comparison
Callioun Count)-', Florida, Chipola Formation; USNM between the fossil form of this genus and its Recent
534494, 8 shells, same locality and formation as preced- counteipart. These detailed studies lead to the follo\ving
obsen'ations:
First, when the underlying sculpture of the Chipola
Distribution: Cirsotrema chipolaiiuiu is a fairly com- Formation Cirsotrema was exposed no difference was
mon species. It is locally abundant at sevei-al Chipola discovered betsveen it and the underlying sculpture ex-
Formation collecting sites along the Chipola River and hibited by C. dalli.
Tenmile and Farley creeks. The factthat it has not been Second, although varices are present on both the
reported from the Oak Grove Sand along the Yellow Chipola Formation Cirsotrema and its Recent counter-
River or from Chipola Formation sites along the part, the varices on the Chipola Formation species are
Apalachicola River may simply reflect the degree ofdif- clearly not as well developed as those ofRecent C. dalli.
ficulty collecting these localities at the appropriate peri- In fact, the varices on C. cliipolamim are at times so
ods oflowwater level. poorly formed that it is difficult to identify them as va-
rices. In C. dalli the costae are fused together to form a
Etymology: Named for the Chipola River. pronounced, elevatedridge (Figures 15-19) that, inwell-
preserved specimens, has a slightly crenulated margin.
Discussion: The genus Cirsotrema has an extensive Conversely, wdth C. chipolamim the varices consist of
evolutionan' histoiy. Sohl (1964) established the genus little more than one or two slightly raised costae (see
Stiiaficostatuin to represent a Cretaceous form of Cir- Figures 10-13). In addition, even in instances where two
sotrema that lacked the faint spiral striations on the bod)' costae are fused together to form a varLx, the fusion is
whorl. By the Eocene the genus Cirsotrema was well often not complete andadistinctline ofdemarcation can
establishedwith numerous species being described from be seen.
different localities (Dockeiy, 1980; Harris and Palmer, Third, when a comparison of the number ofvarices in
1946; Palmer, 1937). Currently, amongextant forms, t^vo relation to the height of the shell was undertaken witli
species ofCirsotrema e.xist in the western Atlantic (Weil well-presewed specimens ofC. dalli and C. chipolamim,
et al, 1999). These are Cirsotrema dalli Rehder, 1945 and a least squares regression analysis was done on the
and Cirsotrema pilsbryi McGint)', 1940. two species, the results showed a significant correlation
Two species of Cirsotrema have also been reported between the height of the shell and the number of va-
from lower Miocene Chipola Formation. Olsson (1967) rices with C. dalli (0.922), and alowcorrelationbetween
identified a specimen collected along the west bank of shell height and the number of \'arices with C. chipo-
the Chipola River south ofTenmile Creekas C. dalli and lamim (0.499). Table 1 below provides the statistical re-
more recently Duerr (2004) described Cirsotrema cirri- sults ofthis study and a comparison ofthe number, size
turn from material collected at several different Chipola range, average size, varix range, and average number of
Formation sites. Olsson (1967) stated that after close varices ofthe specimens used in the analysis.
examination of the Chipola Formation Cirsotrema he As a result ofthe regression analysis two other differ-
found practically no differences between it and the ex- ences between the varices of the two species was also
tantspeciescurrentlylivinginthewesternAtlantic. Since noted. Althoughthevarices appearedatrandomintewals
Olsson's (1967) analysis ofthe Chipola Cirsotrema, over onthe bodywhorls ofboth species, in C. chipolamim the
50 additional specimens have been collected irom a va- first varix did not appear until after the third teleoconch
rietyofChipolalocations. When mostofthese specimens whorl, while in C, dalli varices would appear just after
were closely scrutinized it became apparent to the the protoconch. In addition, when the number ofvarices
present investigators that the Chipola Formation Cir-
sotrema studied by Olsson (1967) was not C. dalli. Table 1. Results of least squares regression analysis compar-
As noted by Clench and Turner (1950), the sculptur- ingshellheightwththenumberofvaricesfoundinC. dalliand
ing on the body whorls of representatives of the genus C. chipoliniitni.
Cirsotrema, is extremely complicated. It was suggested
byClenchandTurner, andobsei"vedin thepresentwork, C. tlaUi C. chipolanu
that two layers of sculpturing are present on the body No. ofspecimens examined 2.3 16
whorls of Cirsotrema dalli. There is an outermost one Correlation coefficient 0.922 0.499
that consists offoliated costae that may or may not join Range ofshell height (mm) .5.8-37.5 5.0^4.2
each other alongtheir convoluted edges and a secondaiy Mean height (mm) 1.5.31 17.21
layeroflaminatedcostae andspiralcords. Because ofthis Range ofvarices 2-27 0-10
Mean no. ofvarices S.82 4.75
dual type ofsculpture Clench andTui'nerwarjiedagainst
G. ^\. schnielz and R. W. Portell, 2007 Page 113
was compared between tlie ditterent species it was discox- Clench and Turner's reason for not using subgenera is
eredthatC. ilalli. on ;xvciage,liadsignilicantlx'morexarici's not stated, but in all probabihtv the authors did not think
than C. chipolaiunu [X = 8.82 \-s. 4.75J. that structural differences between members of this ge-
Table 2 below summarizes the structural dillercnces nus were sufficient to warrant their use.
in shell moqjhologx'bet\\'een C. clalli and C". clupolaiiinn. Since Clench and Turners publication, Weil et al.
In addition to comparing the ditterences between the (1999) and Nakayama (2003) have assigned a number of
shape and number oi \arices between species, the table subgenera to the "enus Cirfiotrcma. It is interesting to
;ilso compares the number ot teleoconch whorls, the note that Ijetween these authors there is not complete
number and arrangement oi costae, the spii"e angles, the agreement as towhich subgeneraare valid. Forexample,
arrangement ofthe costae, and the placement ofvarices Nakayama (2003) used the subgenus Borcnscala to de-
on the boch' whorls. scribe cold-water species that possess thickened, noii
-\nother point worth noting is that C. dalli and ('. blade-like costae, while \Veil et al. (1999) raised the sub-
chipolanum came from xen-differentenvironments. Cir- genus Boreoscala to tlie generic level. In addition, Weil
sotreina dalli lives in cooler continental shelf waters at et al. questions the use ofElcgantiscaki as a subgenus of
depths of37 to 227 m (Clench and Turner, 1950) while Cir.sotrcma while Nakavama retained this subgenus and
C. cliipolauiini thri\"ed in a shallow, warm, tropical, reel used it for many of the species of Cirsotrcma he de-
habitat, -\lthough not a great deal is knowni about how- scribed from the northwest Pacific.
die en\ironment and food supply impact the gro\\'th ot The present authors have followed the more conser-
wentletraps [Robertson (1983a) and Weil et al. (1999)], vative approach used by Clench and Turner (1950), Ab-
diere has been sufficient studies done on the family Mn- bott (1974), Duerr (2004), and Landau et al. (2006) and
ricidae (\'okes, 1973) thatwill ;illow us to speculate as to have not assigned a subgenus to the new Chipola For-
the reasons for the number and stnictural difierenccs mation species.
obsened between the varices of C. dalli and C. chipo- Cirsotrcma togafiim (Hertlein and Strong, 1951) is
lanum. According to \'okes (1973) vaixx (axial gro\\'tli moiphologicallv similar to C. chipolanum. Duerr (2004)
ridge) development in muricids occurs during resting considers C. tos.atum to be awestern cognate ofC. dalli.
stages in shell formation. These stoppages may come Cirsoirema togatuni has also been reported from die
about as the result of food shortages or perhaps as the Pliocene Esnieraldas beds of northwestern Ecuador by
result of environmental changes. The weaker develop- Pitt (1981) and DuShane (1988). Cirsoiremachipolanum
ment and lowernumberofvarices in C. chipolaniiin ma\ differs from C. iogatum in that it has fewer and less
indicate that this species lived in a rather stable environ- distinct spiral cords on the body whorls and the varices
ment where diere were a large number ofprev species are much less developed.
for it to consume. Conversely, C. dalli has more and Cirsotrcma woodringi Olsson, 1967, reportedfrom the
better dev-eloped varices (growth stoppages) which mav Miocene Gatun Formation of Panama and the Pliocene
be due to lack of prev or perhaps increased predation Tamiami Formation at Sunnviand, Florida, is similar to
pressures. C. chipolanum. The main difference between C. woo-
In all probabilits-, C. chipolanum is the ancestral form dringi and C. chipolanum is that C. uoodringi lacks the
of C. dalli. It is the opinion ofthe investigators that C. inclined spiral sculpture that is present on the flat outer
chipolanum probably retreated from the coastal waters surface ofthe costae in C. chipolanum.
into die deeper offshore waters during intenening ice
Cirsotrcma cirrilnm ]3uerr, 2004
ages where itgraduallyevolved into the e.xtant, and mor-
(Figures 20-28)
phologicallv- similar, C. dalli.
Clench andTurner (1950) did not assign a subgeneric Description: Shell medium to large. Turriculate.
name to this genus even though de Boui'v (1909) ditl. Much of protoconch missing. Last protoconch whorl
transitions fi-om asmooth surfaceintowawaxial lamellae
Table 2. A comparison of tlie structural differences in slicll that gradually enlarge into thickened foliated costae.
morphologv between C. dalli and C. chipohniinn. Spire angle 27°. Eight strongly shouldered teleoconch
whorls present. Suture deep. Thirteen crenulated, re-
C dalli ('- chipolaiunu cuiA-ed, axial costae pi'esent on last body whorl. Apical
ends of axial costae shai"p. Costae made up of multiple
Xo. ofspecimens examined 2.3 16
Teleoconch whorls 9-10 7-8 wavy lamella that possesses a fine irregular diamond-
Spire angle 26.5° 27.0° shaped pattern that is inclined adaperturally. Costae
Costae arrangement touching sometimes separated by wide intercostal spaces. Inteix-ostal spaces
separated possess five rounded spiral cords. Cords and intenening
Mean no. ofcostae 20.6 19.1 spaceshaveacancellatesculpturecreatedbyoverlapping
Range in costae number 18-23 17-21 vertical and horizontal threads. Anterior i-eflected pro-
Range in varix number 2-27 0-10 jections ofcostae on last bodv whorl form a basal ridge
Mean varix number 8.82 4.75 with a crenulate outer margin. Costae on basal ridge not
^'arix placement start on 1" start on 3"' fused. Varices absent. Columella short and arched. Ap-
bodv wiiorl bodv wiiorl erture subcircular. No umbilicus.
Page 114 THE NAUTILUS, Vol. 121, No. 3
Figures 20-28. Cirsoirciiui ciiriliiiii Ducrr, 2()()l. 20-23. A|icrliiral, lalcral. aliapci-tiiral. ami hasal \if\\s (jI lioKitxiic I'F 1 1(1972;
nia\irnuiii heiglit2S.5 iiiiii. iiiaxiumm width 11.8 iniii. 24. Mugnitied\ie\vofsculpture cil liliixoiicli (il UF 110972. Scale bar = 2.75
inni. 2.5-2S. Apertural, lateral, abapertural, and hasal views ofparahpe UF 67746; m;v\iiiiiiiii liclght 29.6 nun, nuLviinum width 13.4
mm. Note: Arrows point to apparent varices on paratype UF 67746; thus based upon description by Duerr (2004, p. 1.54-155)
denoting a key diagnostic featuj'e of no varices, tin's paratyjDe was mistakenly identilied. In onr opinion UF 67746 is representative
ol C. cliipnlanuin new species.