The Late Pleistocene Vertebrate Fauna - California … Pleistocene fauna of southwestern Montana is...

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Introduction ThePleistocenefaunaofsouthwesternMontanaisnotwellunderstood.Thisislargelybecauselittleattentionhasbeengiventofossilsitesintheregionuntilrecently.Sincethelate1980s,fossilremainsattheMerrellLocalityhavebeenthesubjectofamajorresearcheffortundertaken,inpart,toenhanceourknowledgeoftheregion’sfaunadur-ingtheLatePleistocene(Dundas1992;Dundas,Hill,andBatten1996). ThisdiscussionprovidesasystematicaccountofthePleistocene vertebrate fauna recovered from the MerrellLocalityandSite,withcommentsonspeciespaleoecology.HillandBatten(thisreport)reportthespatialdistributionof the fossil remains.Atpresent, thevertebrate fauna iscomposedof19species(Table8),mostofwhichoccuratotherLatePleistocenesitesinMontanaandthesurround-ingregion(Graham,Semken,andGraham1987;KurténandAnderson1980;FAUNMAP1994;Harris1985).TwospeciesatMerrellareofparticularinterest;Homotherium serum(Scimitarcat)andOlar buccinator(Trumpeterswan),thesecondofwhichisreportedforthefirsttimeinthefos-silrecordofMontana.Inadditiontothevertebratefauna,specimensofbivalvesandgastropodswerealsorecovered,buthavenotbeenstudied.

Specimen Repository Fossil material collected from the Merrell Localityin1988and1989bytheBLMandtheUM-Missoulaishousedalongwithotherspecimensrecoveredfromthesite,attheMuseumoftheRockies,MontanaStateUniversity-Bozeman,Bozeman,Montana.Acomplete listingofallfaunalremainsintheMuseumoftheRockiescollectionsisprovidedinAppendicesCandD.

Abbreviations and Institutional Acronymsi-lowerincisorm-lowermolarp-lowerpremolarM-uppermolarP-upperpremolarMOR-MuseumoftheRockiesUMT-UniversityofMontanaPaleontologyMuseumUMZM-UniversityofMontanaZoologyMuseum

USNM-UnitedStatesNationalMuseum-SmithsonianInstitution

Systematic PaleontologyPhylumChordata(chordates)

ClassOsteichthyes(bonyfishes)

Referred specimens: MORLI94.5.246,parietalfragment;MORLI94.5.248,suborbitalfragment;MORLI94.5.249,skullbonefragment;MORLI94.5.247,anopercularfrag-mentandaparietalfragment;MORLI95.2.21,skullbonefragment;MORLI95.2.536,trunkvertebra.

Remarks:Thefishremainswereexaminedbypaleoichthy-ologistDr.DouglasLong.Dr.LongdeterminedthatthematerialisinsufficientforfurtheridentificationbelowthelevelofOsteichthyes(bonyfishes).However,thespecimenscomparebestwiththeCatostomidae(suckers)andCyprini-dae(carpsandminnows).Bothfamiliesoffisharefound

The Late Pleistocene Vertebrate FaunaRobert G. Dundas

Figure 81. Late Wisconsinan localities and sites referenced in the text by R. G. Dundas.

Montana1) Flint Creek2) Warm Springs I3) Merrell

Wyoming4) Horned Owl Cave5) Little Canyon Creek Cave6) Prospects Shelter7) Agate Basin8) Sheaman9) Little Box Elder Cave10) Colby11) Natural Trap Cave

Late Wisconsinan localities

Idaho12) Wilson Butte Cave13) Jaguar Cave14) Wasden (Owl Cave)15) Duck Point16) Moonshiner Cave17) Rainbow Beach/ American Falls

California18) Rancho LaBrea

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131416

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Pleistocene Geology, Paleontology, and Prehistoric Archaeology

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Table 8. Late Pleistocene Merrell Locality Fauna.__________________________________________________________________________________

Phylum Mollusca (mollusks) Class Bivalvia (clams and others) Class Gastropoda (snails)Phylum Chordata (chordates) Class Osteichthyes (bony fishes) Class Aves (birds) Order Anseriformes (waterfowl) Family Anatidae (ducks, geese, swans) Genus Anas cf. A. platyrhynchos (Mallard duck) Genus and species Olar buccinator (Trumpeter swan) Class Amphibia (amphibians) Order Anura (frogs and toads) Family Ranidae (ranids) Genus cf. Rana (true frogs) Class Mammalia (mammals) Order Rodentia (rodents) Family Muridae (voles, lemmings, muskrats, mice, and others) Genus and Species Lemmiscus curtatus (sagebrush vole) Genus and Species Ondatra zibethicus (muskrat) Family Sciuridae (squirrels and others) Genus Spermophilus sp. (ground squirrels) Family Castoridae (beavers) Genus and Species Castor canadensis (beaver) Order Carnivora (carnivores) Family Canidae (canids, i.e., dogs) Genus and Species Canis latrans (coyote) Genus and Species Canis lupus (gray or timber wolf) Family Felidae (cats) Genus and Species Homotherium serum (Scimitar cat) Family Ursidae (bears) Genus and Species Ursus sp. (bear) Order Artiodactyla (artiodactyls) Family Antilocapridae (pronghorns) Genus and Species cf. Antilocapra americana (American pronghorn) Family Cervidae (deer) Genus indeterminate (large species) Genus cf. Odocoileus sp. (white-tail or mule deer) Family Bovidae (bovids) Genus Bison sp. (bison) Family Camelidae (camels) Genus Camelops sp. (large camel) Order Perissodactyla (perissodactyls) Family Equidae (horses) Genus Equus sp. (horse) Order Proboscidea (proboscideans) Family Elephantidae (elephants) Genus and Species Mammuthus columbi (Columbian mammoth)__________________________________________________________________________________

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inMontanatoday(Gould1992).Itisnotunreasonabletosuggestthatthefossilspecimensmayrepresentoneorbothofthesegroups.AHolocenespecimenofcf.Catostomus,rightoperculum,wasrecoveredduringthe1995excava-tionsatMerrell.

ClassAves(birds)OrderAnseriformes(waterfowl)

FamilyAnatidae(ducks,geese,swans)

Referred specimen: MOR LI94.5.245, thoracic verte-bra.

Remarks:This specimen was examined by Dr. SteveEmslie,who referred it to theAnatidae.Further identi-fication isnotpossiblebecauseof the lackofadditionaldiagnosticfeatures.

Anas cf.A. platyrhynchos(Mallardduck)

Referred specimen:MORL194.5.455(MS-685,EN-20-2),distalendofalefthumerus.

Remarks:ThisspecimenwasexaminedbyDr.SteveEmslieandfoundtobestcomparewithAnas platyrhynchos.TheMallardisawide-rangingduck,foundthroughoutmostofNorthAmerica,particularlyaroundpondsandfresh-watermarshes(Robbins,Bruun,andZim1966).

GenusOlar(swan)Olar buccinator(Trumpeterswan)

Figure ��

Referred specimen:MORLI96.4.190,proximalendofalefthumerus.

Remarks: MORLI96.4.190wascomparedwithalloftheNorth American swans: Cygnus olor (Mute swan), Olar buccinator (Trumpeter swan), and Cygnus columbianus(Whistlingswan).TheMuteswanisanintroducedspeciesinNorthAmerica,havingbeenbroughtfromEuropeinthe1800s(StokesandStokes1996).TheMORspecimencomparesbestinsizeandmorphologytoOlar buccinator.ItcomparedespeciallywelltoaspecimenofOlar buccina-tor,USNM430266,fromAlaska(Emslie,pers.comm.,1997). TheTrumpeterswan(Olar buccinator)isparticularlyinteresting.Fewfossilremainsofthisspeciesareknown.Fossil specimens have been recovered from Alaska, Or-egon,Iowa,Illinois,Ohio,andFlorida(Brodkorb1964).AlthoughwidespreadinNorthAmericainhistorictimes,

fromAlaskatosouthernCaliforniaandtheGulfCoast,itisraretoday,andoncenearlyextinct(Pough1953).Earlythiscentury,thedrainingofmarshes,hunting,leadpoisoning,andotherenvironmentaldisturbancesnearlyresultedintheextinctionoftheTrumpeterswan.Onlyasmallnumbersurvivedbythe1930s,but,withconservationeffortsandreintroductionback into formerhabitat, thepopulationincreased to more than 3,000 by the 1970s (Udvardy1977).ItisoneofNorthAmerica’slargestbirds,andthelargestmemberoftheswanfamilyinNorthAmerica,withalengthofupto65in(1.65m),awingspanof100in(2.54m),andweighingabout30lbs(13.6kg).Theirhabitatistypicallymarshes, lakes,or riverswithdensevegetation.Theyareknowntonestinoldmuskratorbeaverhousesorsmallisletsinshallowpondsormarshyareas.Foodin-cludesleaves,roots,andseedsofsedgesandotheraquaticplants,andmollusks(Pough1953).Theydiptheirhead

The Late Pleistocene Vertebrate Fauna

Figure 82. Trumpeter swan (Olar buccinator) (MOR LI96.4.190) proximal end of partial lft. humerus: a, anconal; b, palmar; c, ventral; and d, dorsal views.


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andneckinthewatersimilartoaduckwhenfeedingonbottomvegetation (Stokes andStokes1996).They alsoforagealongtheshore.TheRedRockLakesareatotheeastofLimaReservoirisoneofthefewbreedinggroundsleftforthisspeciesinthecontiguousUnitedStates(Robbins,Bruun,andZim1966).

ClassAmphibia(amphibians)OrderAnura(frogsandtoads)

FamilyRanidae(ranids)cf.Rana(truefrogs)

Figure ��

Referred specimen: MORLI95.2.535,distalendofalefthumerus.

Remarks:The specimen isnotScaphiopus (Pelobatidae)because the condylar morphology is different for thatgroup.Thespecimenistoorobustforahylid.OfRanidaeandBufonidae, the specimencomparesbestwithRana.Twenty-fivespeciesofthisgenusoccurinNorthAmericatoday,atleast10ofwhichareknownfromthePleistocene.Mostareaquatic frogs thatpreferquietwater, althoughsomespeciesventurewellintograssyandmoistwoodlandareas(Holman1995).

ClassMammalia(mammals)OrderRodentia(rodents)

FamilyMuridae(voles,lemmings,muskrats,mice,etc.)GenusLemmiscus

Lemmiscus curtatus(sagebrushvole)Figure �4

Referred specimen:MORLI95.2.36,rightdentarywithi1,m1,andm2.

Remarks:Theidentificationisbasedonthespecimenbeing

amicrotinerodentwithfivetrianglesandnolingualwingdevelopmentonthelingualsideoftheanterocap. The sagebrushvolehasbeenrecovered fromseveralLatePleistocenelocalitiesintheregionandoccursintheareatoday.FossiloccurrencesinIdahoincludeWilsonButteCave,JaguarCave,MoonshinerCave,andWasden,whileBellCave,HornedOwlCave,LittleCanyonCreekCave,Prospects Shelter, NaturalTrap Cave, Agate Basin, andLittleBoxElderCaverecordthespeciesinWyoming(Kur-ténandAnderson1980;FAUNMAP1994).InMontana,LemmiscusisknownfromtheLateWisconsinan-ageWarmSpringssite(Rasmussen1974;KurténandAnderson1980)andFalseCougarCave(FAUNMAP1994).Thespeciesistypicallyfoundinsemiarid,openenvironments.Usually,theirhabitatisdominatedbysagebrushandbunchgrasses.Theyareoftenfoundlivingundersagebrushplants,con-structingnests fromits shreddedbark,aswellas leaves,stems,andgrassseed-heads(Zeveloff1988).

GenusOndatra(muskrat)Ondatra zibethicus(muskrat)

Figure ��

Referred specimens:UMT10034,upper right incisor;MORLI94.5.28,rightcalcaneum;MORLI94.5.97,left

Figure 83. Rana distal lft. humerus.

Figure 84. Lemmiscus rt. dentary: a, medial; and b, lateral views.

Figure 85. Ondatra lft. m1: a, occlusal; and b, side views.

a

b

ab

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m1;MORLI94.5.454,partialleftdentarywithm2andm3.

Remarks:UMT10034wascomparedtorodentspecimensin theUniversityofMontanaZoologyMuseum.Of allrodentsinhabitingNorthAmericaduringtheLatePleisto-cene,thesizeandmorphologyoftheincisorcomparesbestwithOndatra zibethicus.Theremainderofthespecimensareclearlyidentifiableasmuskrat,basedoncomparisonswithmodernspecimens. Muskratoccurintheareatoday.Foundinalmostanyaquatic environment, they are common around beaverpondsinthewesternUnitedStates.Aquaticplantscomposemuchofthediet,withapreferenceforcattails.However,theyalsoforageforanimalssuchasfreshwaterclams,snails,frogs,crayfish,turtles,andfish.Muskratsbuildlodgesfromaquaticvegetationandalsoburrowintobanks(Zeveloff1988;JonesandBirney1988).Ondatra zibethicusisalsoknownfromtheLateWisconsinanWarmSprings#1siteinMontana(Rasmussen1974;FAUNMAP1994).Inthesurroundingregion,thespecieshasbeenrecoveredfromtheLateWisconsinandepositsatRainbowBeachandtheDamLocalFaunainIdahoandHornedOwlCaveinWyoming(FAUNMAP1994).

FamilySciuridae(squirrels,etc.)Spermophilussp.(groundsquirrels)

Referred specimen:MORLI94.5.256,partialedentulousrightdentarywithalveoliforthem2andm3present.

Remarks:Speciesidentificationisnotpossibleduetothelackofdentition.Ingeneral,allgroundsquirrelsarebur-rowers,mosthibernate,andmanyarecolonial.Habitatofgroundsquirrelslivingintheareatodayispredominantlysagebrushandbunchgrassrangeland.However,speciessuchasSpermophilus lateralistypicallyinhabitmoistconiferousforests(Zeveloff1988).Recentgroundsquirrelburrowinghas resulted in considerable bioturbation at the MerrellLocality. Spermophilus lateralis is a common ground squirrelfoundintheareatoday.Spermophilus richardsoniimayalsobealocalresidentatthepresenttime.ThereisapossibilitythatapopulationofSpermophilus townsendiicouldreachasfarnorthastheCentennialValleyaswell.InMontana,Spermophilus lateralisisknownfromtheLateWisconsinanatFalseCougarCave,whileSpermophilus richardsoniihasbeenrecoveredfromFalseCougarCaveandWarmSprings#1.OtherspeciesofSpermophilusarealsoknownfromFalseCougarCave(FAUNMAP1994).

FamilyCastoridae(beavers)GenusCastor(beaver)

Castor canadensis(beaver)

Referred specimen:UMT10035,arightp4.

Remarks:Thesizeandmorphologyofthep4fromMer-rellisindistinguishablefrommodernspecimensofCastor canadensisinthecollectionsoftheUniversityofMontanaZoologyMuseum. Beaver live in the region today. Ingeneral, theyarefound wherever permanent water and enough woodyvegetationispresent.Theyhaveagreatcapacityformodi-fyingtheirenvironment.Whenevermovingintoanareawherewaterdepthisnotsufficient,theybuilddamsacrossstreams,wherepossible,usinglogs,sticks,andmud.Thedeepwaterservesanumberoffunctions.Deepwaterpro-tectslodgesandbankdens,facilitatesmovementoffoodandbuildingmaterials,andprovidesagreaterareaforswim-mingduringwinterwhenthewatersurfacemaybecomeice-covered.Also,floodingcausedbydammingsaturatesalargeareaofsurroundingsoil,aconditionconducivetogrowthoffavoritefooditemssuchaswillow,aspen,alder,andcottonwood.Manyotherplantspeciesarealsoeaten,such as grasses in summer.Beaver ponds attract awiderangeofwildlife,includingwaterfowl,fish,muskrats,andothers(Zeveloff1988). Inthefossilrecordoftheregion,Castor canadensisisknown from LateWisconsinan sites at Rainbow Beachand the Dam Local Fauna in Idaho and the Little BoxElderCaveandLittleCanyonCreekCave inWyoming(FAUNMAP1994).

OrderCarnivora(carnivores)FamilyCanidae(canids,i.e.,dogs)

GenusCanis(wolves,jackals,coyotes,domesticdog)Canis latrans(coyote)

Figure ��

Referred specimen:MORLI95.2.309,arightp4.

Remarks:MORLI95.2.309hasawell-developedsecondcusplet,athirdcuspletpresent,andaposteromedialcingu-lum.Thespecimenis13.5mminlengthand6.1mmwide.ItwascomparedwithmodernspecimensofCanis latransandCanis lupus.Ingeneralsize,thespecimenfallswithintherangeofvariationofninespecimensofCanis latransintheUMZM;sizerangeofthenineUMZMspecimens,length8.2-13.8mm,width4.7-6.7mm.ItissmallerthanfivespecimensofCanis lupus intheUMZM;sizerangeof the five UMZM specimens, length 15.8-17.6 mm,



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width7.4-8.7mm.InacomparisonbetweenCanis latransandCanis lupus,thep4ofCanis lupushasmorereducedcusplets,moreoftenlackingawell-developedthirdcuspletandposteromedialcingulum.Thep4ofCanis latranshasasecondcusplet,usuallyapronouncedthirdcusplet,andaposteromedialcingulumextendingbehindthethirdcusplet(Nowak1979).Basedonthesecharacters,theMerrellp4comparesbestwithCanis latrans. Ingeneral,Pleistocenecoyotesarelargerthanmodernspecimens,althoughbyLateWisconsinantimetheyap-proachthesizeoftheRecentforms(KurténandAnderson1980).ThespeciesisoneofthemostcommoncarnivoresintheNorthAmericanLatePleistocene,recoveredfromaround100localities,aboutadozenofwhicharenearbyinIdahoandWyoming(Figure86)(Nowak1979).LateWisconsinanoccurrencesareJaguarCave,RainbowBeach,andtheDamLocalFaunainIdahoandLittleBoxElderCaveinWyoming(FAUNMAP1994). Today, the coyote continues to be a wide-rangingspecies,occupyingmostofNorthAmericaandlivinginavarietyofhabitats(JonesandBirney1988).Theymostoftenoccupyopengrasslands,brushcountry,andbrokenforest (Bekoff1977;Nowak1991).Coyotesareconsid-eredanopportunisticpredatorwithabroadrangeoffooditemsinthediet.Dietvariesseasonallyandaccordingtogeographiclocation,although90percentoffooditemsare

mammals,particularlyrodentsandrabbits.Largeanimalscan be important in the winter diet and plant materialmaybean importantdietarycomponent.Scavenging isnotuncommon(Bekoff1977).

Canis lupus(grayortimberwolf )Figure ��

Referred specimen:MORLI94.5.130,proximalhalfofarightmetatarsal3.

Remarks:MORLI94.5.130comparesverywellinsizetoCanis lupusspecimenUMZM17652.ThemetapodialsofCanis lupusareconsiderablylargerthanCanis latrans.ThespecimendoesnotgenerallycomparewelltoCanis dirusinsize.Canis diruspostcranialelementsaremorerobustthanCanis lupus.MORLI94.5.130isnotoutofthesizerangeforknownCanis dirus,butwouldbeonthesmallendofthesizerange(e.g.,Kisko1967).Thesmallendofthesizerangefordirewolfskeletalelementsisrepresentedmainlybyspecimensfromsoutherndirewolfpopulations.GiventhattheMORmetatarsalcomparesextremelywellinsizetolocalgraywolfspecimens,andinareaswhereCanis dirusandCanis lupusco-occurthedirewolfspecimensaremorerobust, it seems highly unlikely that MOR LI94.5.130couldrepresentaspecimenofCanis dirus.However,Canis lupusandCanis diruslikelyco-occurredinthearea,becauseaspecimenofdirewolfisknownfromnearbyOrrCaveinBeaverheadCounty,Montana(Kurtén1984).Canis lupusisgeographicallywidespreadandoccursatover50locali-tiesofLatePleistoceneageinNorthAmerica(Figure88)(Nowak1979).LateWisconsinanoccurrencesintheregionareLittleBoxElderCaveandProspectsShelterinWyo-ming.Regional“Late-Glacial”recordsincludeJaguarCave,Idaho,andAgateBasinandNaturalTrapCave,Wyoming(FAUNMAP1994).Thespeciesoccupiesabroadrangeofhabitats,mostcommonlyarctictundra,steppe,savannah,

Figure 86. Late Pleistocene occurrences of coyote (after FAUNMAP).

Figure 87. Gray or timber wolf (Canis lupus) (MOR LI 94.5.130) proximal half of a rt. metatarsal 3: a, medial; b, lateral; c, posterior; and d, proximal views.

NA locations 3

1000 Km

Merrell

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andforests(Nowak1991).Today,thegraywolfisoneofNorthAmerica’stoppredators,feedingprimarilyondeer,elk,caribou,moose,andbison(Zeveloff1988).

FamilyFelidae(cats)GenusHomotherium(Scimitarcats)Homotherium serum(Scimitarcat)

Figures (�9-90)

Referred specimens: UMT 10001, proximal left ulna;UMT10002,leftmetacarpal4.

Remarks: These two specimensofHomotherium serum,recoveredfromunproveniencedbeachcollectionsbytheUniversityofMontanafieldcrewin1989,weredescribedbyDundas(1992).AsampleofUMT10001,aproximalleftulna,wassubmittedtoBetaAnalyticforradiocarbondating;however,thespecimenlackeddatableprotein(LesDavis,pers.comm.,1997). Oneofthemostsignificantdiscoveriesamongthefau-nalremains,thisspeciesisrareinthePleistoceneofNorthAmerica,andthisrepresentsitsfirstrecordinMontana.Homotherium serumisknownfrom18Rancholabrean-agesites(Figure90),theclosestoccurrencesbeingattheDuckPointandAmericanFallslocalitiesinIdaho(Jeffersonand


NA locations 1

1000 Km

Merrell

Figure 88. Late Pleistocene occurrences of gray or timber wolf (after FAUNMAP).

NA locations 2

1000 Km

Merrell

Figure 90. Late Pleistocene occurrences of Scimitar cat (after FAUNMAP).

Figure 89. Scimitar cat (Homotherium serum) (UMT 100002): (a-c) proximal lft. ulna; and (d-f) lft. metacarpal

a b c

d e f


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Tejada-Flores1993).ConsistentwithmostrecordsofHo-motherium(JeffersonandTejada-Flores1993),theMerrellspecimensrepresentoneindividual.

FamilyUrsidae(bears)Ursus sp.

Figure 9�

Referredspecimen:UMT10050,leftdentaryfragment.

Remarks:Anearlier referralof thedentary fragment toUrsus americanus(Dundas1992;Dundas,Hill,andBat-ten1996)wasbasedonacomparisonofonlyacoupleofspecimens.ExaminationofovertwodozenmandiblesofUrsus arctos(Grizzlybear)andUrsus americanus(Americanblackbear)inthecollectionsoftheUniversityofMontanaMuseumofZoology indicates thatdiagnosticcharactersnecessarytoidentifythespecimentospeciesarelacking.Thespecimenis,therefore,referredtoUrsussp.

OrderArtiodactyla(artiodactyls)FamilyAntilocapridae(pronghorns)

cf.Antilocapra americana(Americanpronghorn)

Referred specimens:UMT10049,pelvicfragment;MORLI94.5.456,proximalendofaproximalphalange;MORLI95.2.537,proximalphalange.

Remarks:MORLI95.2.537,aproximalphalange,com-pareswellwithAntilocapra americanaspecimenUMZM4027, although the Merrell specimen is slightly larger.Pronghorn occupy grassland habitat (Jones and Birney1988).Thespeciesoccursintheareatoday(Zeveloff1988).Notsurprisingly,consideringthespeciesdistribution,itisfoundatseverallateWisconsinansitesintheregion,includ-ingRainbowBeach,OwlCave,andtheDamLocalFaunainIdahoandHornedOwlCave,LittleBoxElderCave,Prospects Shelter, and NaturalTrap Cave inWyoming.Other“Late-Glacial”sitesinWyomingincludeAgateBasin,Colby,andSheaman(FAUNMAP1994).

FamilyCervidae(deer)GenusandSpeciesindeterminate(largecervid)

Referred specimens:MORLI94.5.455,lefti1ori2;MORLI94.5.457,deciduouslowerleftmolariformtooth.

Remarks:MORLI94.5.455,alowerincisor,compareswellwithCervus elaphus,butisrathersmallforelk.Thespeci-menalsocompareswellwithsomespecimensofOdocoileus,butislargeforthisgenusofcervid.MORLI94.5.457,adeciduouslowermolariformtooth,wascomparedwiththedeciduousdentitionsofspecimensofCervus elaphus(elk)and Alces alces (moose).The variation in the deciduousdentitionofbothoftheselargecervidsisgreatenoughtoprecludeassignmentoftheMerrellspecimentoagenus.BothspecimensarebestidentifiedasbeingreferredtoasCervidae,albeitfromlargecervids.

cf.Ococoileussp.(white-tailormuledeer)

Referred specimen: MORuncat.(MS-685,EN-2),proxi-malphalange.

Remarks:The proximal phalange compares well withUMZM4945,aproximalphalangeofOdocoileus hemionus(muledeer).Deeroccupyavarietyofhabitatsfrombrushy,woodedareastoopenplains.BothspeciesofOdocoileusoc-curintheareatoday(Zeveloff1988).Odocoileus hemionusisknownfromseveralLateWisconsinansitesinWyoming,includingHornedOwlCave,LittleBoxElderCave,andLittleCanyonCreekCave.TheknownWisconsinan-agefossilrecordofthetwospeciesofOdocoileusispoorfortheregion(FAUNMAP1994).

FamilyBovidae(bovids)Bisonsp.(bison)Figures 9�-94

Figure 91. Bear (Ursus sp.) (UMT 10050) lft. dentary fragment: a, lateral and b, medial views.

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b

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Referred specimens:UMT10013,partiallowerrightm3;UMT10032,proximalphalange;UMT10064,partialleftradius/ulnadiaphysis;UMT10071,distalendofameta-podial;MORLI91.1.3,naviculocuboid;MORLI91.1.5,partialproximalendofametacarpal3/4;MORLI93.2.1,

partialleftinnominate;MORLI94.5.458,toothfragment;MORLI94.5.460,leftmedialphalange;MORLI94.5.462,proximalendofarightulna;MORLI95.2.535,proximalphalange; MOR L191.1.3 (MS-562, BLM#27), rightscaphoid.

Remarks:UMT10032isaproximalphalangemissingtheproximalepiphysis.Thespecimenisclearlyfromajuvenile.Theremainderofthematerialisfromadultanimals. Bisonaregrazersthatoccupymainlyopen,grasslandhabitatinNorthAmerica.Theyoccasionallyuseforestedareas,particularlyforshadeandfeedingwhenthesnowistoodeep(Zeveloff1988).Bisonoccurredintheareaupintohistoric timebeforepopulationswere reduceddra-maticallyandthespeciesnearlybecameextinctinthelate1800s(Zeveloff1988).Inthefossilrecord,bisonareknownfrommanyWisconsinansitesintheregion(FAUNMAP1994).

FamilyCamelidae(camels)Camelopssp.(largecamel)

Figure 9�

Referred specimens: UMT 10020, left partial dentarywithm3;MORLI94.5.86,toothfragmentconsistingof

Figure 92. Bison (Bison sp.) (UMT 10071) distal end of metapodial: a, distal; b, anterior; and c, side views.

Figure 93. Bison (Bison sp.) (UMT 10032) proximal phalange: a, anterior and posterior views; b, side; and c, proximal views.

Figure 94. Bison (Bison sp.) (MOR LI 94.5.460) medial phalange: a, posterior; b, lft. proximal; and c, side

a

b c

a b

c

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bc


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thebuccalsideofanM2orM3;MORLI94.5.459,distalendofaproximalphalange;MORLI94.5.461,proximalepiphysisofaproximalphalange.

Remarks:Morphologically,UMT10020,a leftdentaryfragmentwithm3,compareswellwithRanchoLaBreaspecimensofCamelops hesternusinthecollectionsoftheUniversityofCaliforniaMuseumofPaleontology(Berke-ley).CamelopswasalsoreportedfromtheLateWisconsinan

lefthalfofamedialphalange;MORLI95.2.134,medialphalange;MORLI95.2.155,uneruptedpartialupperleftmolariformtooth,nottheP2orM3;MORLI95.2.162,mandibularsymphysiswithalveoliforrighti1,i2,i3,andlefti1;MORLI96.4.96,rightuppermolariformtooth,nottheP2orM3;MORLI96.4.191,distalhalfofaradius.

Remarks:Bothadultandjuvenilehorsematerialisrepre-sented.Noattemptismadeheretoassignthismaterialtoaspecies,fortworeasons.First,thematerialisoflimitedvaluetaxonomically,notpossessingdiagnosticcharactersnecessary for species identification. Second, given thecurrent state of confusion concerning the species leveltaxonomyofthegenusEquus,littlevalueexistsinassigningthematerialtospecies. EquusmaterialisnotuncommonintheLatePleisto-ceneofMontana,althoughmostrecordsareunpublished.IncomparisontootherMontanasitescontaininghorse,whichtypicallyhavefewspecimens,aconsiderablecollec-tionofEquusmaterialwasrecoveredfromtheFlintCreeksite(Dundas1991).

OrderProboscidea(proboscideans)FamilyElephantidae(elephants)GenusMammuthus(mammoths)

Mammuthus columbi (Columbianmammoth)Figures 9�-9�

Referred specimens:UMT10019,leftmetatarsal3;UMT10027,fibula;UMT10028,patella;UMT10029,rightmetatarsal3;UMT10038,partiallowerrightm3;UMT10052,proximalendofaleftscapula;UMT10054,righttibia;UMT10055,leftmetacarpal5;UMT10056,rightmagnum;UMT10057,rightmetacarpal(4?);UMT10059,right cuboid; UMT 10060, proximal phalange; UMT10061,rightmetacarpal1;UMT10065,leftcuneiform;UMT10066,proximalphalangeofdigit3;UMT10067,proximalphalange;UMT10068,proximalphalangeofdigit5;UMT10069,proximalphalange;UMT10070,rightlunar;UMT10072,leftmetacarpal2;UMT10075,partialleftmagnum;UMT10076,partialrightmagnum;UMT10077,rightectocuneiform;UMT10078,partialrightnavicular;UMT10079,partialleftunciform;UMT10080,partialrightcalcaneum;UMT10083,atlas;UMT10085,medialphalange;MORLI94.5.98,phalange;MORLI94.5.100,tooth;MORLI94.5.114,metapodialmissingtheproximalend;MORLI94.5.115,?leftmetacarpal5;MORLI94.5.120,proximalphalange;MORLI94.5.134,basicranial fragment with one occipital condyle; MORLI94.5.363,proximalphalange;MORLI94.450,partialtooth;MORLI94.5.451,partialtooth;MORLI94.5.541,partialtooth;MORLI95.2.118,proximalendofaleftulna;

FlintCreek site,Montana (Dundas1991).NearbyLateWisconsinanoccurrences in Idaho include JaguarCave,Dam Local Fauna, and Rainbow Beach (FAUNMAP1994).

OrderPerissodactyla(perissodactyls)FamilyEquidae(horses)

Equussp.(horse)

Referred specimens: UMT 10023, lower molariformtooth,notthep2orm3;UMT10039,lowerrightmo-lariformtooth,notthep2orm3;UMT10043,partiallyeruptedlowerrightmolariformtooth;UMT10048,leftcuneiform; UMT 10051, partial distal phalanx; UMT10062,lowerrightmolariformtooth,notthep2orm3;MORLI91.1.4,partialrightnavicular;MORLI91.1.6,partial medial phalange; MOR LI93.2.2, partial leftinnominate; MOR LI94.5.119, left trapezium; MORLI94.5.185,proximalsesamoidofpes;MORLI95.2.23,distal end of a proximal phalange; MOR LI95.2.106,

Figure 95. Camelops hesternus partial lft. dentary with m3: a, occlusal; and b, buccal views.

a

b

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MORLI95.2.140,partialinnominate,mostlytheilium;MORLI95.2.156,distalphalange;MORLI96.4.63,rightnavicular;MORLI96.4.90,proximalendofaleftscapula;MORLI96.4.91,metapodial;MORLI96.4.95,phalange;MORLI96.4.99,leftastragalus;MORLI96.4.182,rightcalcaneum; MOR LI96.4.183, right astragalus; MORLI96.4.184, left metatarsal 5; MOR LI96.4.185, rightmetatarsal3;MORLI96.4.186,leftmetatarsal4;MORLI96.4.187,sesamoid;MORLI96.4.188,rightmetatarsal1;MORLI96.4.189,distalphalange;MORLI96.4.192,rightmetatarsal4;MORLI96.4.193,leftcalcaneum.

Remarks: UMT 10029 is a right metatarsal 3 with anunfuseddistalepiphysis,suggestingasubadult.Nearlyalloftheidentifiablemammothremainsappearstobefromadults.UMT10027,afibula,wasradiocarbondated. ThereissomedisagreementregardingNorthAmericanmammothtaxonomy(Maglio1973;KurténandAnderson1980;Graham1986;AgenbroadandBarton1991)and,untilacomprehensiverevisionisundertakenandageneralconsensusreached,itisparticularlyimportanttocitewhichtaxonomyisbeingused.Here,thetaxonomyfollowsMaglio(1973).DentalmeasurementsweretakenusingproceduresoutlinedbyMaglio(1973).

SeveralpartialteethfromMerrellallowsomeconsid-erationtobegiventospeciesidentification.Platecount,enamelthickness,andlamellarfrequencyarereportedforthefollowingspecimens,wherepossible:

UMT10038-Theanteriorpartofthelowerrightm3isbrokenoff.TheremainderofUMT10038consistsof15totalplates,11ofwhichareinwear.Theenamelthicknessis2-2.8mm,andthelamellarfrequencyisseven.

MOR LI94.5.100- 20 plates, 11 of which are in wear;enamelthicknessof2mm;lamellarfrequencyof6.

MOR LI94.5.450- a molar fragment with 5.5 plates.Enamelthicknessis2mm.

MORLI94.5.451-amolarfragmentwith4plates.Enamelthicknessis1.5mm.

MORLI94.5.452-amolarfragmentwith7plates.Enamelthicknessis2mm.

Figure 96. Occlusal surfaces of Columbian mammoth (Mammuthus columbi): a, MOR LI 94.5.100; (b-c), MOR LI94.5.450-452.

a

b

Figure 97. Columbian mammoth (Mammuthus columbi) distribution relative to Pleistocene glaciation.


c d


90

Unfortunately,mostof theMerrellmammothteethareincomplete.Asaresult,thecharacteristicofplatespertoothisoflittlevaluehere.Maglio(1973)recognizedtwoLatePleistocenespeciesofmammothinNorthAmerica:Mammuthus columbi(Columbianmammoth)andMam-muthus primigenius (Woollymammoth).Maglio furtherrecognizedwhathetermeda“typicalform”anda“derivedform”ofColumbianmammoth.Thecharacteristicsusedtodistinguishthespecieslistedbelowarebasedonthe3rdmolar. Considering the Merrell material, the lamellar fre-quencyof6-7andenamelthicknessrangingfrom1.5-2.8mmsupporttheassignmentofthesespecimenstoMam-muthus columbi(Table9).

Discussion TheMerrellfaunaiscomprisedof21taxa,ofwhich15aremammals.Althoughmanymembersofthefaunacurrentlyliveinthearea,severalbecameextinctinNorthAmericaneartheendofthePleistocene,includingHomoth-erium serum,Camelops,Equus,andMammuthus columbi.Inregardtominimumnumberofindividuals,allvertebratespeciesattheMerrellSitearerepresentedbyaminimumof one individual, except for Bison sp., Equus sp., andMammuthus columbi.AtleasttwoBisonarerepresented;ajuvenileispresentwhiletheremainderofthematerialisadult.Likewise,Equusisrepresentedbyaminimumoftwoindividuals,basedonpartiallyerupteddentitionindicat-ingayounganimal,whilemostofthematerialisadult.Probablymorethantwoindividualsarerepresentedbasedonstratigraphiclocationofthejuveniledentitions.Mam-mothisthemostabundantmaterialatMerrell.However,determiningaminimumnumberofindividualsbasedonthefragmentarynatureofmanyofthespecimensprobablyunderestimatestheactualnumberofindividuals.Neverthe-less,atleastthreeindividualsofmammotharepresent,twoadultsandonesubadult(orjuvenile). Ingeneral,discussionoffaunulesattheMerrellSiteisnotpossible,inpart,duetotheconsiderablebioturbation

present at the site.However, considering thefive strati-graphicunitsatMerrell,thefaunalremainswererecoveredfrom deposits of at least two ages. Specimens from thedebrisflow(stratumD),onthenorthendofthesite,datetoca.27,000BPand22,000BP.RemainsfromstratumB(andupperstratumA)aredatedtoca.40,000BP(Hill,thisreport:Table9). Severalmembersofthefaunaareindicativeofaperen-nial,slow-movingwaterbodyinthearea.Theswan,duck,muskrat,andbeaverallsuggestastream,marsh,or lakesetting. Thesedimentarysequencecontainsavarietyoffossilremains(cf.Dundas1992).AlistofthevertebratefaunarecoveredfromtheMerrellLocalityispresentedasTable8.ThematerialsstudiedbyDundaswerecollectedbyateamdirectedbyFoorin1989andwereinitiallyconservedintheUniversityofMontanaMuseumofPaleontologyver-tebratecollections(Dundas1992:9).Mammothremainsarepresent inboththestratumB(LL2)andstratumDdeposits(Albanese,thisreportandHill,thisreport).BoneswerealsoobservedintheuppermostpartofandonthetopofstratumA(alongitsboundarywithstratumB).OthervertebrateremainsthatarebiostratigraphictimemarkersincludeaPleistocenevariantofhorse,Yesterday’scamel,andScimitarcat.

InvertebratesChristopher L. Hill

Invertebrate fossils include molluscs and ostracods.FragmentsofgastropodsandbivalveswererecoveredfromtheuppermostpartofstratumB(LL2e,Figure6).IntactgastropodsandostracodswererecoveredfromLL3a(Figure6).FragmentsofmolluscsandostracodsoccurthroughouttheuppersectionsofstrataCandD.Bump(1989)reportsthepresenceof four generaof gastropods and abivalvegenus from the sediments containing and overlying thevertebrateremains.Allareassociatedwithaquatichabitats,includingstreamsettingsorponds.

Table 9. Comparison of Lamellar Frequency, Enamel Thickness, and Plates Per Tooth Between M. columbi Variants.

Characteristics M. columbi M. columbi M. primigenius (typical form) (derived form)

lamellar frequency 5-7 7-9 7-12 (lophs per 100 mm)enamel thickness 2.0-3.0 mm 1.5-2.0 mm 1.0-2.0 mm

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