Climatic Gradients in the Distribution of Kansas Land Snails (Mollusca: Gastropoda)

7 Pages·2002·3.7 MB·English

by  Barry B Miller

KIRTLANDIA
The Cleveland Museum of Natural History
July 2002 Number 53:5-11
CLIMATIC GRADIENTS IN THE DISTRIBUTION
OF KANSAS LAND SNAILS (MOLLUSCA: GASTROPODA)
BARRYB.MILLER
DepartmentofGeology
KentStateUniversity,Kent,Ohio44242-0001
MICHAELJ.S.TEVESZ,DANIELAC.SMITH,ANDMICHAELA.GATES
DepartmentofBiological,Geological,andEnvironmentalSciences
ClevelandStateUniversity,Cleveland,Ohio44115-2406
[email protected]
ABSTRACT
Thedistributionof64speciesoflandsnails(Mollusca:Gastropoda)acrossthe 105coun-
tiesoftheStateofKansaswasanalyzedbyprincipalcomponentsanalysistodeterminethe
relationshipbetweenspeciesoccurrenceandclimaticfactors.Significantbioticresponsesof
speciesassemblagestoclimaticgradientsinprecipitationandinannualtemperatureweredis-
covered. Inparticular,totalspeciesdiversityispositivelycorrelatedwithprecipitation(annu-
alorsummeralone)acrossthecountiesofKansas,andthedistributionsofmajorclustersof
gastropodspecieswerecorrelatedwithaverageannualtemperature(orlatitude).
Introduction temperaturerangewas50.6to58.9°F,andtheaveragenum-
This paper presents an analysis of the relationships beroffrost-freedaysvariedbetween154and198.
between the distribution of species assemblages of land Because the State of Kansas shows pronounced geo-
snails (Mollusca: Gastropoda) across the counties of the graphicdinesinclimaticconditions,ouraimwastoexplore
StateofKansas and gradients ofclimatic variables across whetherthere is afaunal response to these gradients in a
thosecounties.Forthelarge,mid-continentalstateofKansas groupoforganismslikelytobedependentuponclimaticfac-
intheyearsrepresentedbyourdata,theaverageannualpre- tors.Inasimilargeographicstudy,KadmonandHeller(1998)
cipitationacrossthe105geopoliticaldivisions(thecounties) foundastrongcorrelationbetween species distributionsof
rangedfrom15.82to41.68inches,whiletheannualaverage landsnailsinIsraelandtheclimaticgradientsfoundthere.
6 MILLERANDOTHERS No.53
MaterialsandMethods
Themostrecentpublishedsurveyofspeciesoflandsnails
inKansasremainsthemonographofLeonard(1959),which
givesdistributionmapsforeachsnailspeciesinthecounties
ofthe state. Table 1 lists the 64 gastropod taxa found in
Kansas,usingnomenclatureupdatedaccordingtothesystem-
atic treatment ofTurgeon et al. (1988) and earlier works
(Pilsbry, 1948;Taylor, 1960;Taylor, 1965).Thedistribution
maps were converted into a presence/absence data table,
where each of the 105 counties was scored according to
whethereach ofthe species was recorded as present. The
countiesofKansaswerecodedaccordingtoaletter-and-num- Figure1,MapofthecountiesofKansas,alongwiththeirlet-
bercheckerboardscheme(Figure1),withlowerlettersofthe ter-and-number codes, as follows: Al, Cherokee; A2,
alphabettotheeastandhighernumberstothenorth.Thus,the Crawford; A3, Bourbon; A4, Linn; A5, Miami; A6,
mostsoutheasterncounty(Cherokee)wascodedAl,andthe Johnson;A7,Wyandotte;A8,Leavenworth;B1,Labette;B2,
mostnorthwesterncounty(Cheyenne)wascoded08. Neosho; B3, Allen; B4, Anderson; B5, Franklin; B6,
Climaticdataforthesamplelocalitiesweretakenfromthe Douglas; B7, Jefferson; B8,Atchison; B9, Doniphan; Cl,
nearestreportingstationoftheUnitedStatesWeatherBureau Montgomery; C2,Wilson; C3,Woodson; C4,Coffey;C5,
fortheperiod 1899-1938,correspondingtothemajorityof Osage; C6, Shawnee; C7, Jackson; C8, Brown; Dl,
thecollectiondatesforthespecimenscollectedbyLeonard Chautauqua; D2, Elk; D3, Greenwood; D4, Lyon; D5,
(1959)fortheMuseumofNaturalHistoryattheUniversityof Wabaunsee; D7, Pottawatomie; D8, Nemaha; El, Cowley;
Kansas.Thefiveclimaticparametersthatwereusedcorre- E2,Butler;E4,Chase;E5,Morris;E6,Geary;E7,Riley;E8,
spondtoaveragevaluesforthemainweatherstationineach Marshall; F4, Marion; F5, Dickinson; F7, Clay; F8,
county,usingpublishedmaps(Kincer, 1941).Theirdescrip- Washington;Gl,Sumner;G2,Sedgwick;G3,Harvey;G4,
tionsaregiveninTable2,alongwithlatitudeandlongitude. McPherson; G5, Saline; G6, Ottawa; G7, Cloud; G8,
AllstatisticalanalyseswereperformedusingtheSPLUS Republic;HI,Harper;H2,Kingman;H3,Reno;H4,Rice;
2000softwarepackage(MathSoft, 1999).Weusedprincipal H5, Ellsworth;H6, Lincoln; H7,Mitchell; H8,Jewell; II,
componentsanalysis(Morrison,1967;Gauch,1982)toreduce Barber; 12, Pratt; 13, Stafford; 14, Barton; 16, Russell; 17,
thecomplexityofthedistributionsofthe64speciesacrossthe Osborne;18,Smith;Jl,Comanche;J2,Kiowa;J3,Edwards;
105countiesinKansas.Thistechniqueiscommonlyusedin J4,Pawnee;J5,Rush;J6,Ellis;J7,Rooks;J8,Phillips;Kl,
analyses of geographic distributions ofbiotic assemblages Clark;K2,Ford;K3,Hodgeman;K4,Ness;K6,Trego;K7,
(KadmonandHeller,1998)toreducethemultivariatedimen- Graham;K8,Norton;LI,Meade;L2,Gray;L4,Lane;L6,
sionalityoftheoriginaldata.Itconstructslinearcombinations Gove;L7,Sheridan;L8,Decatur;Ml,Seward;M2,Haskell;
of the original variables (in this case, the presences and M3,Finney;M4,Scott;Nl,Stevens;N2,Grant;N3,Kearny;
absencesof64species)thatmaximallyencompassthevaria- N4, Wichita; N6, Logan; N7, Thomas; N8, Rawlins; 01,
tionintheoriginaldata.Inparticular,thefirstprincipalcom- Morton; 02, Stanton; 03, Hamilton; 04, Greeley; 06,
ponentaccountsforthegreatestvarianceinthespeciesdata; Wallace;07,Sherman;08,Cheyenne.
the secondcomponentisperpendiculartoanduncorrelated
withthefirstcomponent,anditaccountsforthesecondlargest
amountofvariation;thethirdcomponentisorthogonaltothe thevariationamongall 105countiesinthefirstthreeprin-
firsttwoandaccountsforthenextlargestamountofvariation; cipalcomponents.Principalcomponent1,whichaccounted
etc. These synthetic variables thus represent uncorrelated for20.8percentofthetotalvariationinthedata,loadedpos-
aspectsofspeciesdistributionsacrossthecountiesofKansas. itively on all 64 species, except Succinea pseudavara,
Theprincipalcomponentsforspeciesdistributionthenwere Succineavaginacontorta,andGastrocoptacristata\inother
relatedtolatitude,longitude,andthefivespecificclimaticvari- words,itcontrastedtheoccurrencesofthesethreespecies
ablesforthe105countiesbyusingsimplelinearregressionand againstthoseoftheother61species,amongwhichthehigh-
correlationtechniques(Gauch,1982;Sokal&Rohlf,1995). est loadings were attributed to Zonitoides arboreus,
Anguispiraalternata,Philomycuscarolinianus,Strobilops
ResultsandDiscussion labyrinthicus,Gastrocoptaarmifera,Gastrocoptacontrac-
Principalcomponentsanalysisofdistributionsof64gas- ta,andCarychiumexile.Thesecondprincipalcomponent,
tropodspecies accountingforanother 11.2percentofthevariation, con-
Principalcomponentsanalysisofthedistributionaldata, trasted19speciesagainsttheother45.Thethirdcomponent
basedonthematrixofcorrelations amongthe64 species comprised an additional 6.2 percent ofthe variation and
variates,wassuccessfulincapturingasignificantfractionof contrastedthedistributionsofadifferentsetof30species
2002 CLIMATIC GRADIENTS 7
Table1.Systematicsofthegastropodspecies(orsubspecies)foundinKansas.The28speciessubsetusedinasecondanalysis
describedinthetextisindicatedwithboldface.
Order Family Species Order Family Species
Basommatophora Punctidae
Carychiidae Punctumminutissimum(I.Lea,1841)
Carychiumexiguum Pupillidae
(Say,1822) Gastrocoptaarmifera(Say,1821)
Carychiumexileexile Gastrocoptacontracta(Say,1822)
I.Lea,1842 Gastrocoptacorticaria(Say,1816)
Stylommatophora
Gastrocoptacristata
Bulimulidae (Pilsbry&Vanatta,1900)
Bulimulusdealbatusdealbatus Gastrocoptaholzingeri(Sterki,1889)
(Say,1821)
Gastrocoptapellucidahordeacella
Cochlicopidae (Pfeiffer,1841)
Cochlicopalubricalubrica Gastrocoptapentodon(Say,1821)
(Miller,1774)
Gastrocoptaproceraprocera
Discidae (Gould,1840)
Anguispiraalternataalternata Gastrocoptatappaniana
(Say,1816) (C.B.Adams,1842)
Haplotrematidae Pupoidesalbilabris
Haplotremaconcavum (C.B.Adams,1841)
(Say,1821) Pupoideshordaceus(Gabb,1866)
Helicarionidae PupoidesinomatusVanatta,1915
Euconuluschersinuspolygyratus
(Say,1821) Vertigomilium(Gould,1840)
Helicodiscidae VertigoovataovataSay,1822
Heliocodiscuseigenmannieigenmanni VertigotridentataWolf,1870
(Pilsbry,1900) Succineidae
Heliocodiscusparallelus Catinellavagans(Pilsbry,1900)
(Say,1817)
Catinellawandae(Webb,1953)
Heliocodiscussingleyanussingleyanus
(Pilsbry,1890) Oxylomaretusum(I.Lea,1834)
Philomycidae SuccineaconcordialisGould,1848
Philomycuscarolinianus(Bose,1802) SuccineaovalisSay,1817
Polygyridae SuccineapseudavaraWebb,1954
Allogonaprofunda(Say,1821) SuccineavaginacontortaLee,1951
Euchemotremaleaialiciae Strobilopsidae
(A.Binney,1841) Strobilopslabyrinthicus(Say,1817)
Mesodonclausus(Say,1821) Vitrinidae
Deroceraslaeve(Muller,1774)
Mesodoninflectusinflectus(Say,1821)
Mesodonthyroidusthyroidus Zonitidae Hawaiiaminusculaminuscula
(Say,1816) (A.Binney,1840)
Polygyradorfeuillianadorfeuilliana Mesomphinxcupreusozarkensis
(I.Lea,1838) (Rafinesque,1831)
Polygyradorfeuillianasampsoni Nesovitreaelectrina(Gould,1841)
(I.Lea,1838)
Polygyrajacksonijacksoni Nesovilreaidentataidentata(Say,1823)
(Bland,1866) Paravitreacapsellacapsella
(Gould,1851)
Stenotremahirsutumhirsutum
(Say,1817) Paravitreasignificans(Bland,1866)
Stenotremastenotrema{Pfeiffer,1842) Paravitreasimpsoni(Pilsbry,1889)
TTrriiooddooppssiissaclbroalgaibnriisCaallll,eni18(S8a6y,1816) SSttrr(iiPaiatltusurbraraymm&ielriiFedurimroin(sEas.l,iS1s.9M0o6r)se,1859)
Triodopsisdivesta(Gould,1848)
Ventridensligera(Say,1821)
Triodopsismultilineataalgonquinensis
(Say,1821) Zonitoidesarboreus(Say,1816)
Triodopsismultilineatamultilineata Valloniidae
(Say,1821) ValloniaparvulaSterki,1893
Triodopsisneglecta(Pilsbry,1899)
8 MILLERANDOTHERS No.53
Table2.Thesevenclimaticvariablesandcorrelationsof
5 thefirstthreeprincipalcomponents(comps.)ofspecies
distributionsof64gastropodspecieswiththeseclimatic
0 variables.Thelastfivevariablesrepresentannualaverages.
2 -5
Comp.1 Comp.2 Comp.3
Component-10 Latitude(°N) 0.151 0.303 -0.115
Longitude(°W) -0.730 -0.040 0.099
-15 Annualprecipitation(inches) 0.730 0.010 -0.132
Summerprecipitation(inches) 0.721 0.034 -0.150
-20 Annualtemperature(°F) 0.125 -0.203 -0.023
Julytemperature(°F) -0.128 -0.091 -0.040
-25 A1 Numberoffrost-freedays 0.436 0.157 0.013
-3.5 -1.0 1.5 4.0 6.5 9.0 11.5 14.0
Component1 Table3.Correlationsbetweenprincipalcomponent
(comp.)scoresbasedon28gastropodspeciesandclimatic
variablesinthecountiesofKansas.
Species Comp.1 Comp.2 Comp.3
Euchemotremaleaialiciae 0.241 -0.136 0.001
Mesodonthyroidusthyroidus 0.139 -0.009 -0.332
3 Mesodonclausus 0.163 0.202 0.092
Triodopsisalbolabrisalleni 0.219 0.213 -0.073
Bulimulusdealbatusdealbatus 0.170 -0.122 -0.104
Component
Euconuluschersinuspolygyratus 0.230 0.011 -0.097
Nesovitreaelectrina 0.244 0.136 -0.048
Nesovitreaidentataidentata 0.249 -0.033 -0.085
Paravitreasignificans 0.082 -0.030 -0.321
Hawaiiaminusculaminuscula 0.179 -0.180 0.166
Striaturamilium 0.091 0.385 0.351
Striaturameridionalis 0.091 0.386 0.350
Zonitoidesarboreus 0.247 -0.108 -0.011
Anguispiraalternataalternata 0.258 0.061 -0.130
Heliocodiscusparallelus 0.180 -0.236 0.149
Figure2.LocationofthecountiesofKansas(indicatedwith Punctumminutissimum 0.167 0.238 0.053
thelocalitycodesofFigure 1)inthespacedefinedbythe Philomycuscarolinianus 0.204 0.028 -0.266
firstthreeprincipalcomponentsbasedonthedistributionof Succineaconcordialis 0.110 0.141 0.161
64gastropodspecies. Catinellavagans 0.070 0.186 0.169
Strobilopslabyrinthicus 0.254 0.102 -0.195
Gastrocoptaarmifera 0.188 -0.254 0.199
Gastrocoptacontracta 0.244 -0.113 -0.009
againsttheremaining34.Thus,thefirstthreeprincipalcom- Gastrocoptapentodon 0.189 0.099 -0.174
ponentstogetheraccountfor38percentofthevariationin Gastrocoptatappaniana 0.160 -0.089 0.066
the distributional dataof64 gastropod species across the Gastrocoptaproceraprocera 0.151 -0.222 0.262
105countiesofKansas. Pupoidesalbilabris 0.167 -0.230 0.199
Inspectionofthelocationoftheindividualcountiesin Valloniaparvula 0.157 -0.282 0.286
thethreemostimportantdimensionsofprincipalcompo- Carychiumexileexile 0.214 0.247 -0.013
nentsspace(Figure2)revealsthatthemosteasterncoun-
tiesofKansas(codesA1 toD8)occuratthehighendof
thefirstprincipalcomponent, thatthe mostsoutheastern Relationshipsbetweenspeciesdistributionsandclimatic
county(Al:Cherokee)isdistinctwithrespecttothesec- gradients
ondprincipal component, andthatthere is some separa- Table2givesthecorrelationsbetweenthefirstthreeprin-
tionoftheeasterncounties,aswellasH3(RenoCounty) cipalcomponentsandthevaluesforeachofthesevencli-
alongthethirdcomponent.Thesuperpositionofnearlyall maticfactorsforeachcounty.Itisclear,forexample,thatthe
ofthewesterncountiesindicatethattheyaredistinctwith firstcomponentis stronglypositivelycorrelatedwithtotal
respecttogastropodassemblages. precipitation(r=0.730,P<0.001)andwithsummerpre-
r
2002 CLIMATIC GRADIENTS 9
cipitation( =0.721,P<0.001),butstronglynegativelycor-
relatedwithlongitude(r=0.730,P<0.001).Asmightbe
expectedfromthemid-continentallocationofKansas,there
isastrongpositivecorrelationbetweenannualandsummer
precipitation(r=0.997,P<0.001).Furthermore,thisstate
partlywaschosenforthisstudybecauseofthestrongrela-
tionship(r=0.981,P<0.001)betweenlongitudeandpre-
cipitation,witharemarkablylineargradientfromthewetter
east to the drier west (see Figure 3). However, Figure 4
demonstratesthatannualprecipitationisagoodpredictorof
thefirstprincipalcomponentonlyfortheeasterncounties,
where there generally is a higher diversity of gastropod
species(Figure5).Amuchbetterpredictorofthefirstcom-
ponent(r=0.976,P<0.001)issimplythespeciesdiversity
(Figure6),althoughasnotedabovenotallspeciesloadpos- Longitude
itivelyonthiscomponent.Furthermore,thesupeipositionof Figure3.Relationshipbetweenlongitudeandtotalannual
manyofthewesterncountiesalongthefirstcomponentthat precipitationinKansas.
wasevidentbeforecanbeexplained,inlargepart,bytheir
depauperategastropodpopulations.
Thesecondprincipalcomponentismoststronglyposi-
tivelycorrelatedwithlatitude(r=0.303,P<0.01)andneg-
ativelycorrelated(r=0.203,P<0.01)withannualtemper-
ature(Table2).Sincehigherlatitudesgenerallycorrespond
withlowertemperaturesoverthecountiesofKansas (r=
0.800,P<0.001),theserelationshipsimplythatthesecond
mostimportantaxisofgastropodspeciesdistributioncanbe
explainedpartially by asecond, less pronouncedclimatic
gradient. The third principal component correlates only
weakly with climatic variables; the highest correlation is
withsummerprecipitation,butitisnotstatisticallysignifi-
cant(r=0.150,P>0.05).
Principalcomponentsanalysisofdistributionsof28
selectedgastropodspecies Figure 4. Relationship between total annual precipitation
Inordertotesttherobustnessoftheseresults,asecondprin- and scores on the first principal component ofgastropod
cipalcomponentanalysiswasundertakenusingasubsetcon- speciesdistributionsinKansas.
sistingof28ofthe64gastropodspeciesfoundinKansas.Table
1indicatesinboldfacetypethespeciesselectedforthisanaly-
sis,whichrepresentmostofthefamiliesofgastropods.They
includemostofthespeciesthatloadedhighlyintheanalysisof
tohfetfhuell10da5tacsoeutn,tiasesliisntetdheabsopvaec.eFdiegfuirneed7bsyhtohwesfitrhsettdiwsopopsriitnicoin- B9 C6
palcomponents.Again,alongitudinaltrendisevident(with A<ep|F 03
mostofthewesterncountiessuperimposed),plusthesepara- A4 B3 El
tionThofeBfi4rs(tApnridnecrispoalncCoomupnotyn)enatloinngthtihsecsaesceolnodacdoemdppoonseitnitv.ely AA3kB1CC85C°47dr™K!i’?f£®8
onall28species(seeTable3),withthehighestcontributions C3 ffl! S’M ^M4
provided by Anguispira altemata, Strobilops labyrinthicus, C1C2 *
NN8»
Nesovitreaindentata,Zonitoidesarboreus,Nesovitreaelectri-
na,Gastrocoptacontracta,andEuchemotremaleai.Manyof IS
thesesamespeciescontributedhighlytothefirstcomponentof
thefull64-speciesdataset.Onceagain,scoresonthefirstcom-
ponentacrossthecountiesofKansaswerehighlypositively Figure 5. Relationship between longitude and gastropod
correlatedwiththeclimaticfactorsofannualprecipitation(r= speciesdiversityinKansas.
.
10 MILLERANDOTHERS No.53
0.784, P<0.001; Figure 8) and summerprecipitation (r=
0.781,P<0.001),werehighlynegativelycorrelatedwithlon-
gitude(r=0.773,P<0.001),andwereverystronglycorrelat-
edwithspeciesdiversity(r=0.966,P<0.001).
Thesecondprincipalcomponentmoststronglycontrasted
the distributions ofStriatum meridionalis. Striatum milium,
Carychium exile, and Punctum minutissimum with those of
Valloniaparvula, Gastrocopta armifera, Helicodiscusparal-
lelus,andPupoidesalbilabris.Thiscomponentwassignificant-
lycorrelatedonlywithlatitude(r=0.238,P<0.05).Thethird
componentcontrastedthedistributionsofStriatummeridion-
alis,Striatummilium,Valloniaparvula,andGastrocoptapro-
cerawiththoseofMesodonthyroidus,Paravitreasignificans,
0 5 10 15 20 25 30 35 and Philomycus carolinianus. It was correlated significantly
Numberofspecies onlywithtwoclimaticvariables:positivelywithlatitude(r=
Figure6.Relationshipbetweengastropodspeciesdiversity 0.372,P<0.01)andnegativelywithaveragetemperature(r=
andthefirstprincipalcomponent. 0.231,P<0.05);ofcourse,thesetwovariablesarecorrelated
negativelywitheachother,asnotedabove.
Thecongruenceoftheresultsforthefullsetof64gastropod
speciesfoundinKansasandtheselectedsubsetof28species
strengthensourinterpretationthattherehasbeenasignificant
bioticresponseofthisgroupofgastropodstoclimaticgradients
inprecipitation(fromeasttowestacrossthecheckerboardof
Kansancounties)and,lessstrongly,inannualtemperature(from
southtonorth).Theseconclusionsarecomparabletothesimi-
larlystrongresponsefoundbyKadmonandHeller(1998)ofthe
landsnailsofIsraeltoastrongrainfallgradientfromnorthto
south.Toourknowledge,thepresentstudyrepresentsthefirst
analysisoftherelationshipbetweenlandsnaildistributionsand
climaticfactorsinthecentralregionoftheUnitedStates.
Acknowledgements
Figure7.LocationofthecountiesofKansasinthespace We are gratefulforthe helpful comments ofJ. Heller
definedbythefirsttwoprincipalcomponentsbasedonthe (Hebrew University ofJerusalem) andJ. B. Keiper(The
distributionof28gastropodspecies. ClevelandMuseumofNaturalHistory)onthemanuscript.
WealsoappreciatethefinancialsupportofClevelandState
University for publication costs, through a supplemental
EFFRDgranttoM.Tevesz.
References
Gauch, H. G., Jr. 1982. Multivariate Analysis in Community
Ecology. Ordination, Chapter 4, p. 109-172. Cambridge
UniversityPress,Cambridge,England.
Kadmon,R.,andJ.Heller.1998.Modellingfaunalresponsestocli-
maticgradientswithGIS:landsnailsasacasestudy.Journalof
Biogeography,25:527-539.
KincIenr,G.J.HBa.mb19r4i1d.gCeli(emda.)t.eCalnidmawteeatahnedrMdaatnaf(oUrSthDeAU.YSe.a,rpb.oo6k8)5,-7U.4S1.
GovernmentPrintingOffice,Washington.
Leonard,A.B.1959.HandbookofGastropodsofKansas.University
ofKansasMuseumofNaturalHistory,MiscellaneousPublication
Figure 8. Relationship between total annual precipitation 20.Lawrence.225p.
andscoresonthefirstprincipalcomponentof28gastropod MathSoft 1999. SPLUS 2000. DataAnalysisProductsDivision;
speciesdistributionsinKansas. MathSoft,Inc.,Seattle.
2002 CLIMATIC GRADIENTS 11
Morrison, D. F. 1967. Multivariate Statistical Methods. The Taylor,D.W. 1965.ThestudyofPleistocenenonmarinemollusks
structure ofmultivariate observations: I. Principal compo- inNorthAmerica,p.597-611.InH.E.WrightandD.G.Frey
nents,Chapter7,p.221-258.McGraw-Hill,NewYork. (eds.), The Quaternary of the United States. Princeton
Pilsbry,H.A.1948.LandMolluscaofNorthAmerica.American UniversityPress,Princeton.
AcademyofNaturalSciences,Monograph3,2:521-1113. Turgeon,D.D.,A.E.Bogan,E.V.Coan,W.K.Emerson,W.G.
SokaPlr,acRt.icRe.,oafnSdtaFt.isJ.tiRcoshlinf.Bi1o9l9o5g.iBcialomReetsreya:rcThh.eLPirinnecairplreesgraensd- TNLyhaoomnmesps,sooWnf.,AqaL.unadtPJir.actDt.I,nWvCie.lrltieF.barmasEt..es1R9of8pr8eo.rm,CotAhm.emUSoncnihteaeldntdeSmStaca,iteensFt.iafGni.dc
5si4o5n-,6C08h.apWt.erH.14,Frp.ee4m5a1n-5&44C,o.a,ndNCeowrrYeolartki.on,Chapter15,p. PCuabnlaidcaa:tioMnol16l.usAkmse.riAcmaenrFiicshaenrieFsisShoecriieetsy,SBoectiheetsyda.Sp2e7c7iapl.
Taylor,D.W. 1960. LateCenozoicmolluscanfaunasfromthe
HighPlains. United States Geological Survey Professional
Paper337.94p.