# List of the Cenozoic life of South Dakota

This list of the Cenozoic life of South Dakota contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of South Dakota and are between 66 million and 10,000 years of age.

## A

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* †Adeloblarina
** †Adeloblarina berklandi – or unidentified comparable form
* †Adjidaumo
** †Adjidaumo lophatus
** †Adjidaumo minutus
* †Aelurodon
** †Aelurodon ferox
** †Aelurodon taxoides
* †Aepinacodon
** †Aepinacodon deflectus – type locality for species
* Life restoration of the Miocene camel Aepycamelus, or the long-necked camel. Heinrich Harder (1920). †Aepycamelus
* †Agnotocastor
** †Agnotocastor coloradensis
** †Agnotocastor praetereadens – type locality for species
* †Agriochoerus
** †Agriochoerus antiquus
** †Agriochoerus gaudryi – type locality for species
* †Alilepus – tentative report
* †Alismaphyllites
** †Alismaphyllites grandifolius
* †Allantodiopsis
** †Allantodiopsis erosa
* Alligator
** Fossilized skeleton of the Oligocene Alligator prenasalis †Alligator prenasalis – type locality for species
* †Allomys
** †Allomys harkseni
** †Allomys storeri – type locality for species
* †Allophaiomys
** †Allophaiomys pliocaenicus
* †Alwoodia
* †Ambystoma
** †Ambystoma minshalli
** †Ambystoma tigrinum
* Life restoration of the Miocene elephant relative Amebelodon. Margret Flinsch (1932). †Amebelodon
* †Ameiseophis
** †Ameiseophis robinsoni
* †Ampelopsis
** †Ampelopsis acerifolia
* †Amphechinus
** †Amphechinus horncloudi
* †Amphicaenopus
** †Amphicaenopus platycephalus – type locality for species
* †Amynodontopsis
** †Amynodontopsis bodei
* †Anchitherium
** †Anchitherium clarencei
* †Ansomys
** †Ansomys cyanotephrus – type locality for species
* Antilocapra
** †Antilocapra americana
* Apalone
** †Apalone leucopotamica
* †Aphelops
** †Aphelops megalodus
* †Apternodus
** †Apternodus mediaevus
* †Archaeocyon
** †Archaeocyon leptodus
** †Archaeocyon pavidus
* †Archaeohippus
** †Archaeohippus blackbergi – or unidentified comparable form
* †Archaeolagus
** †Archaeolagus macrocephalus – type locality for species
** †Archaeolagus primigenius – type locality for species
* Life restoration of the Eocene-Oligocene entelodont mammal Archaeotherium †Archaeotherium
** †Archaeotherium lemleyi – type locality for species
** †Archaeotherium marshi – type locality for species
** †Archaeotherium mortoni
** †Archaeotherium trippensis – type locality for species
* †Arctodus
** †Arctodus simus
* †Arctonasua
* †Arretotherium
** †Arretotherium fricki
** †Arretotherium leptodus – type locality for species
* Azolla
** †Azolla schopfi – type locality for species

## B

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* Fossilized skull of the Miocene-Pliocene false saber-toothed cat Barbourofelis †Barbourofelis
** †Barbourofelis whitfordi
* †Barbouromeryx
** †Barbouromeryx trigonocorneus
* †Bathornis
** †Bathornis celeripes
** †Bathornis veredus
* Bison
** †Bison latifrons
* Blarina
** †Blarina carolinensis – or unidentified comparable form
* †Boochoerus
** †Boochoerus angustus – type locality for species
* †Bothriodon
** †Bothriodon americanus – type locality for species
** †Bothriodon rostratus
* †Brachyerix
** †Brachyerix incertis – or unidentified comparable form
* †Brachygaulus – or unidentified comparable form
* †Brachypsalis
** †Brachypsalis modicus
* Skeletal reconstruction of the Eocene-Oligocene bear-dog Brachyrhynchocyon †Brachyrhynchocyon
** †Brachyrhynchocyon dodgei
* †Brontops
** †Brontops bicornutus
** †Brontops brachycephalus
** †Brontops dispar
** †Brontops robustus – type locality for species
** †Brontops tyleri – type locality for species
* Bufo
** †Bufo pliocompactilis
** †Bufo woodhousei
* Buteo
** †Buteo grangeri – type locality for species

## C

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* †Calamagras
** †Calamagras angulatus
** †Calamagras weigeli
* †Calippus
** †Calippus martini
** †Calippus placidus
* Life restoration of the Pliocene-Holocene camel Camelops †Camelops
* Canis
** †Canis dirus – or unidentified comparable form
** †Canis latrans
** †Canis lupus
* †Capacikala
** †Capacikala parvus
* †Capatanka
** †Capatanka gaulodon
** †Capatanka minor
* †Carpocyon
** †Carpocyon robustus
* Castor
** †Castor canadensis – or unidentified comparable form
** †Castor peninsulatus
* †Catostomus
* Celtis
* †Centetodon
** †Centetodon magnus
** †Centetodon marginalis
** †Centetodon wolffi
* Cercidiphyllum
** †Cercidiphyllum arcticum
* A living Charina boa Charina
** †Charina prebottae
* Chrysemys
** †Chrysemys antiqua
* †Clinopternodus
** †Clinopternodus gracilis
* Cnemidophorus
* †Colodon
** †Colodon cingulatus
** †Colodon occidentalis
* †Copemys
** †Copemys longidens
* †Coprophis – type locality for genus
** †Coprophis dakotaensis – type locality for species
* †Cormocyon
** †Cormocyon haydeni – type locality for species
* †Cormohipparion
** †Cormohipparion fricki
** †Cormohipparion quinni
* †Cosoryx
** †Cosoryx furcatus
* Restoration of the Miocene palaeomerycid Cranioceras, a relative of modern deer, with anachronistic human to scale †Cranioceras
** †Cranioceras unicornis
* Crotalus
* †Crucimys
** †Crucimys milleri
* †Cupidinimus
** †Cupidinimus smaragdinus – type locality for species
* †Cymaprimadon
** †Cymaprimadon kenni – type locality for species
* †Cynarctoides
** †Cynarctoides acridens
** †Cynarctoides lemur
** †Cynarctoides roii
* †Cynarctus
** †Cynarctus crucidens
* †Cynodesmus
** †Cynodesmus thooides
* Cynomys

## D

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* †Dakotallomys
** †Dakotallomys lillegraveni
** †Dakotallomys pelycomyoides
* †Dakotaophis – type locality for genus
** †Dakotaophis greeni – type locality for species
* Life restoration of the Eocene-Miocene bear dog Daphoenus †Daphoenus
** †Daphoenus hartshornianus
** †Daphoenus vetus
* †Dendrochen – type locality for genus
** †Dendrochen robusta – type locality for species
* †Desmathyus
** †Desmathyus pinensis
* †Desmatippus
** †Desmatippus texanus
* †Desmatochoerus
** †Desmatochoerus megalodon
* †Desmocyon
** †Desmocyon thomsoni
* †Diceratherium
** †Diceratherium annectens
** †Diceratherium armatum – type locality for species
** †Diceratherium radtkei
** †Diceratherium tridactylum – type locality for species
* †Dikkomys
** †Dikkomys matthewi
* †Dinictis
** †Dinictis felina
* †Dinohyus
* †Dipoides
* †Disallomys
** †Disallomys robustus
* †Domnina
** †Domnina dakotensis – type locality for species
** †Domnina gradata
** †Domnina greeni – type locality for species
* †Domninoides
** †Domninoides riparensis – type locality for species
* †Douglassciurus
** †Douglassciurus bjorki – type locality for species
* †Downsimus
** †Downsimus chadwicki – type locality for species
* †Duchesnehippus
** †Duchesnehippus intermedius
* Illustration of the fossilized jaws and teeth of the Eocene brontothere mammal Duchesneodus †Duchesneodus
** †Duchesneodus uintensis

## E

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* †Ectopocynus
** †Ectopocynus antiquus
* †Ekgmowechashala
** †Ekgmowechashala philotau – type locality for species
* Elaphe
** †Elaphe nebraskensis
** †Elaphe vulpina
* †Elomeryx
** †Elomeryx armatus – type locality for species
** †Elomeryx garbanii – type locality for species
* †Enhydrocyon
** †Enhydrocyon crassidens – type locality for species
** †Enhydrocyon pahinsintewakpa
* Life restoration of the Eocene-Oligocene mammal Entelodon. Charles R. Knight. †Entelodon
** †Entelodon coarctatus – or unidentified comparable form
* †Entoptychus
** †Entoptychus leptophrys
* †Eopelobates
** †Eopelobates grandis – type locality for species
* †Epeiromys
* †Epicyon
** †Epicyon saevus
* Equus
** †Equus francisci
** †Equus giganteus – or unidentified comparable form
* †Etheostoma
* Life restoration of the Miocene elephant relative Eubelodon †Eubelodon
** †Eubelodon morrilli
* †Eucastor
** †Eucastor tortus
* †Eucommia
** †Eucommia serrata
* Eumeces
** †Eumeces septentrionalis
* †Eumys
** †Eumys brachyodus
** †Eumys elegans
* †Eusmilus
** †Eusmilus sicarius
* †Eutypomys
** †Eutypomys montanensis – or unidentified comparable form
** †Eutypomys thomsoni – type locality for species
** †Eutypomys wilsoni – or unidentified comparable form

## F

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* A living Ficus, or fig tree Ficus
** †Ficus artocarpoides
** †Ficus subtruncata
* †Florentiamys
** †Florentiamys agnewi – type locality for species
** †Florentiamys tiptoni
* †Fossorcastor
** †Fossorcastor brachyceps

## G

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* †Galbreathia
** †Galbreathia novellus
* Geomys
* †Geringia
** †Geringia gloveri
** †Geringia mcgregori
* †Gigantocamelus
** †Gigantocamelus spatulus
* Glyptostrobus
** †Glyptostrobus nordenskioldi
* Mounted fossilized skeleton of the Miocene-Pleistocene elephant relative Gomphotherium †Gomphotherium
** †Gomphotherium obscurum
* †Grangerimus
** †Grangerimus dakotensis
* Graptemys
* †Gregorymys
** †Gregorymys curtus – type locality for species
** †Gregorymys formosus – type locality for species
* †Gripholagomys – type locality for genus
** †Gripholagomys lavocati – type locality for species
* †Guildayomys
** †Guildayomys hibbardi – or unidentified comparable form

## H

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* †Haplomys
** †Haplomys galbreathi – type locality for species
* †Heliscomys
** †Heliscomys senex
* †Hemiauchenia
* †Hemicyon
** †Hemicyon barbouri
* †Heptacodon
** †Heptacodon curtus – type locality for species
** †Heptacodon gibbiceps – type locality for species
** †Heptacodon occidentale
* †Herpetotherium
** †Herpetotherium fugax
** †Herpetotherium youngi
* Life restoration of the Eocene-Oligocene dog Hesperocyon. Robert Bruce Horsfall (1913). †Hesperocyon
** †Hesperocyon gregarius
* †Hesperolagomys – tentative report
* †Hesperopetes
** †Hesperopetes blacki – type locality for species
** †Hesperopetes jamesi – type locality for species
* †Hesperotestudo
** †Hesperotestudo niobrarensis
* Heterodon
* †Heteromeryx
** †Heteromeryx dispar – type locality for species
* †Hibbarderix
** †Hibbarderix obfuscatus
* †Hibbardomys
** †Hibbardomys marthae – or unidentified comparable form
** †Hibbardomys zakrzewskii
* Life restoration of a herd of the Miocene-Pleistocene horse Hipparion. Heinrich Harder (1920). †Hipparion
** †Hipparion tehonense
* †Hippotherium
** †Hippotherium dolichops – type locality for species
* †Hitonkala
** †Hitonkala andersontau – type locality for species
* †Homotherium – or unidentified comparable form
* †Hoplophoneus
** †Hoplophoneus cerebralis
** †Hoplophoneus mentalis
** †Hoplophoneus occidentalis
** †Hoplophoneus primaevus
* Life restoration of the Eocene-Miocene creodont mammal Hyaenodon †Hyaenodon
** †Hyaenodon brevirostrus – type locality for species
** †Hyaenodon crucians
** †Hyaenodon horridus
** †Hyaenodon montanus – or unidentified comparable form
** †Hyaenodon mustelinus – type locality for species
* Hyla
* †Hypertragulus
** †Hypertragulus calcaratus
** †Hypertragulus dakotensis – type locality for species
* †Hypisodus
** †Hypisodus minimus
* Life restoration of the Miocene horse Hypohippus. Heinrich Harder (1920). †Hypohippus
* †Hypolagus
** †Hypolagus fontinalis – type locality for species
** †Hypolagus vetus – or unidentified comparable form
* †Hyporhina – type locality for genus
** †Hyporhina antiqua – type locality for species
* †Hyracodon
** †Hyracodon leidyanus – type locality for species
** †Hyracodon nebraskensis
** †Hyracodon priscidens – or unidentified comparable form

## I

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* Ictalurus
* †Ischyrocyon
** †Ischyrocyon gidleyi
* Mounted fossilized skeleton of the Eocene-Oligocene rodent Ischyromys †Ischyromys
** †Ischyromys typus

## J

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* †Javazapus
** †Javazapus weeksi

## K

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* †Kirkomys
** †Kirkomys martintau
** †Kirkomys nebraskensis

## L

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* †Lambdoceras
** †Lambdoceras hessei – type locality for species
* Lampropeltis
** †Lampropeltis similis
* †Leidymys
** †Leidymys blacki
** †Leidymys juxtaparvulus
* Lepisosteus
* Lepomis
* †Leptarctus
** †Leptarctus primus – type locality for species
* Restoration of the Oligocene-Miocene oreodont mammal Leptauchenia †Leptauchenia
** †Leptauchenia decora – type locality for species
** †Leptauchenia major – type locality for species
* †Leptictis
** †Leptictis dakotensis
** †Leptictis haydeni
* †Leptochoerus
** †Leptochoerus elegans
** †Leptochoerus supremus – type locality for species
* †Leptocyon
** †Leptocyon delicatus – type locality for species
** †Leptocyon douglassi
** †Leptocyon gregorii
** †Leptocyon matthewi
** †Leptocyon vafer – or unidentified comparable form
** †Leptocyon vulpinus
* Life restoration of the Eocene-Oligocene even-toed ungulate Leptomeryx †Leptomeryx
** †Leptomeryx evansi
* †Leptoromys
** †Leptoromys wilsoni – type locality for species
* Lepus
** †Lepus americanus – or unidentified comparable form
** †Lepus ennisianus – or unidentified comparable form
* †Lignimus
** †Lignimus austridakotensis – type locality for species
* †Limnoecus
** †Limnoecus compressus – or unidentified comparable form
** †Limnoecus niobrarensis
* †Longirostromeryx
** †Longirostromeryx wellsi – type locality for species

## M

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* †Macrogenis
** †Macrogenis crassigenis
* †Macrognathomys
** †Macrognathomys gemmacolis – type locality for species
* †Macrorhineura – type locality for genus
** †Macrorhineura skinneri – type locality for species
* †Mammacyon
** †Mammacyon obtusidens – type locality for species
* †Mammuthus
** Life restoration of a herd of Mammuthus columbi, or Columbian mammoths. The extent of the fur depicted is hypothetical. Charles R. Knight (1909). †Mammuthus columbi
** †Mammuthus primigenius
* †Manitsha – type locality for genus
** †Manitsha tanka – type locality for species
* Martes
** †Martes campestris
* †Megacerops
** †Megacerops coloradensis
** †Megacerops curtus
* †Megachoerus – tentative report
** †Megachoerus latidens – type locality for species
* †Megalagus
** †Megalagus primitivus – or unidentified comparable form
** †Megalagus turgidus
* †Megaleptictis
** †Megaleptictis altidens
* †Megalictis
** †Megalictis ferox – type locality for species
* †Megalonyx
** †Megalonyx leptostomus
** †Megalonyx wheatleyi
* †Megapaloelodus – type locality for genus
** †Megapaloelodus connectens – type locality for species
* †Megasminthus
** †Megasminthus gladiofex – type locality for species
** †Megasminthus tiheni
* †Megoreodon
** †Megoreodon grandis
* †Meniscomys
** †Meniscomys hippodus
* Life restoration of the Miocene rhinoceros Menoceras †Menoceras
** †Menoceras barbouri
* †Menops
** †Menops marshi
** †Menops serotinus
** †Menops walcotti
* †Merychippus
** †Merychippus insignis
* †Merychyus
** †Merychyus arenarum
** †Merychyus minimus
** †Merychyus novomexicanus
* Restorative portrait of the Oligocene-Miocene oreodont mammal Merycochoerus †Merycochoerus
** †Merycochoerus chelydra
** †Merycochoerus matthewi – type locality for species
* †Merycodus
** †Merycodus major – or unidentified comparable form
** †Merycodus necatus
* †Merycoides
** †Merycoides longiceps
** †Merycoides pariogonus – or unidentified comparable form
* †Merycoidodon
** †Merycoidodon bullatus – type locality for species
** †Merycoidodon culbertsoni – type locality for species
** †Merycoidodon major
* Skull fossils of the Oligocene-Miocene dog Mesocyon †Mesocyon
** †Mesocyon temnodon
* †Mesohippus
** †Mesohippus bairdi
** †Mesohippus exoletus
* †Mesoreodon
** †Mesoreodon chelonyx
** †Mesoreodon minor
* †Mesoscalops
* Restoration of the Eocene-Miocene swamp rhinoceros Metamynodon. Charles R. Knight (1896). †Metamynodon
** †Metamynodon chadronensis – type locality for species
** †Metamynodon planifrons
* †Michenia
** †Michenia exilis
* Microtus
** †Microtus meadensis
** †Microtus paroperarius
* Mictomys
** †Mictomys kansasensis
* †Mimomys
** †Mimomys dakotaensis
* †Miniochoerus
** †Miniochoerus affinis
** †Miniochoerus forsythae
** †Miniochoerus gracilis
** †Miniochoerus starkensis – type locality for species
* †Mioheteromys
** †Mioheteromys arcarius
* Fossilized skull of the Eocene-Oligocene three-toed horse Miohippus †Miohippus
** †Miohippus annectens – type locality for species
** †Miohippus equiceps
** †Miohippus equinanus
** †Miohippus gemmarosae – or unidentified comparable form
** †Miohippus gidleyi – type locality for species
** †Miohippus grandis
** †Miohippus intermedius – type locality for species
** †Miohippus obliquidens – type locality for species
* †Mionictis
** †Mionictis pristinus
* †Miortyx – type locality for genus
** †Miortyx teres – type locality for species
* †Miospermophilus – or unidentified comparable form
* †Monosaulax
** †Monosaulax curtus – or unidentified comparable form
* †Moropus
* Mustela
* †Mustelavus
** †Mustelavus priscus – type locality for species
* †Mylagaulus
** †Mylagaulus sesquipedalis – or unidentified comparable form
* †Mystipterus
** †Mystipterus martini – or unidentified comparable form

## N

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* Partial fossilized mandible of the Miocene-Pliocene horse Nannippus †Nannippus
* †Nanotragulus
** †Nanotragulus loomisi
** †Nanotragulus ordinatus – type locality for species
* †Nelumbago
** †Nelumbago montanum
* †Neohipparion – type locality for genus
** †Neohipparion affine – type locality for species
* †Neonatrix
** †Neonatrix elongata
* Neotoma
** †Neotoma amplidonta – type locality for species
* Nerodia
** †Nerodia sipedon
* Nettion
** †Nettion greeni – type locality for species
* †Nexuotapirus
** †Nexuotapirus marslandensis
* †Niglarodon
** †Niglarodon koerneri
* Illustration of the fossilized skull of the Oligocene false saber-toothed cat Nimravus †Nimravus
** †Nimravus sectator – type locality for species
* †Nothodipoides
** †Nothodipoides planus
* Notophthalmus
** †Notophthalmus crassus – type locality for species
* †Nototamias
** †Nototamias quadratus
* †Notropis
* †Noturus – tentative report

## O

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
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* L
* M
* N
* O
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* T
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* X
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* †Ocajila
** †Ocajila makpiyahe – type locality for species
* †Octacodon
** †Octacodon valens – type locality for species
* †Ogmophis
** †Ogmophis miocompactus – type locality for species
* †Oligoryctes
** †Oligoryctes altitalonidus
* †Oligoscalops
** †Oligoscalops galbreathi
* †Oligospermophilus
* †Oligotheriomys
** †Oligotheriomys magnus – type locality for species
* Ondatra
** †Ondatra annectens
* Onychomys
** †Onychomys pedroensis
* †Oreodontoides
** †Oreodontoides oregonensis
* Ortalis
** †Ortalis pollicaris – type locality for species
* †Osbornodon
** †Osbornodon sesnoni
* †Otarocyon
** †Otarocyon cooki
** †Otarocyon macdonaldi – type locality for species
* †Oxetocyon
** †Oxetocyon cuspidatus – type locality for species
* Mounted fossilized skeleton of the Oligocene-Miocene camel Oxydactylus †Oxydactylus
** †Oxydactylus lacota – type locality for species
** †Oxydactylus wyomingensis – or unidentified comparable form

## P

* A
* B
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* M
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* X
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* †Paciculus
** †Paciculus cedrus – type locality for species
** †Paciculus montanus – or unidentified comparable form
** †Paciculus nebraskensis – or unidentified comparable form
** †Paciculus woodi
* †Palaeoborus
** †Palaeoborus rosatus – type locality for species
* Spiral-shaped fossilized burrow and associated skeleton of the Oligocene-Miocene beaver Palaeocastor †Palaeocastor
** †Palaeocastor peninsulatus
** †Palaeocastor wahlerti
* †Palaeogale
** †Palaeogale dorothiae – type locality for species
** †Palaeogale sectoria
* †Palaeolagus
** †Palaeolagus burkei
** †Palaeolagus haydeni
** †Palaeolagus hypsodus
** †Palaeolagus intermedius
** †Palaeolagus philoi – type locality for species
* †Palaeonossax – type locality for genus
** †Palaeonossax senectus – type locality for species
* †Paleoheterodon
** †Paleoheterodon tiheni
* †Parablastomeryx
** †Parablastomeryx gregorii
* †Paracrax
** †Paracrax gigantea – type locality for species
** †Paracrax wetmorei – type locality for species
* †Paradaphoenus
** †Paradaphoenus minimus
** †Paradaphoenus tooheyi – type locality for species
* †Paradjidaumo
** †Paradjidaumo trilophus
* †Paraenhydrocyon
** †Paraenhydrocyon robustus
* †Parahippus
** †Parahippus cognatus – or unidentified comparable form
** †Parahippus pawniensis
** †Parahippus pristinus – type locality for species
* †Paramerychyus
** †Paramerychyus harrisonensis
** †Paramerychyus relictus
* †Paramys
** †Paramys relictus
* †Paranymphaea
** †Paranymphaea crassifolia
* †Paranyroca – type locality for genus
** †Paranyroca magna – type locality for species
* †Parapliosaccomys
** †Parapliosaccomys hibbardi – or unidentified related form
* †Paratomarctus
** †Paratomarctus euthos
* †Paratylopus
** †Paratylopus labiatus
* †Parictis
** †Parictis dakotensis – type locality for species
** †Parictis gilpini – type locality for species
** †Parictis major – type locality for species
** †Parictis parvus – type locality for species
* †Parvericius
** †Parvericius montanus
* Fossilized skull of the Eocene-Oligocene lizard Peltosaurus †Peltosaurus
** †Peltosaurus granulosus
* †Pelycomys
** †Pelycomys placidus
* †Penetrigonias
** †Penetrigonias dakotensis
* †Peraceras
** †Peraceras superciliosum
* †Perchoerus
** †Perchoerus minor
** †Perchoerus nanus
** †Perchoerus probus – or unidentified comparable form
* Perognathus
** †Perognathus brevidens
** †Perognathus coquorum – or unidentified comparable form
** †Perognathus trojectioansrum
* Peromyscus
* †Philotrox
** †Philotrox condoni
* †Phlaocyon
** †Phlaocyon minor
* Phrynosoma
** †Phrynosoma douglassi
* †Planera
** †Planera raynoldsi
* Restoration of a herd of alarmed Miocene-Pleistocene peccaries of the genus Platygonus. Charles R. Knight (1922). †Platygonus
* †Plesiosorex
** †Plesiosorex coloradensis
** †Plesiosorex donroosai – type locality for species
* †Pleurolicus
** †Pleurolicus clasoni
** †Pleurolicus dakotensis – type locality for species
** †Pleurolicus sulcifrons
* †Pliauchenia
** †Pliauchenia magnifontis
* †Pliogale
** †Pliogale manka
* Fossilized skull of the Miocene horse Pliohippus †Pliohippus
** †Pliohippus pernix
* †Pliophenacomys
** †Pliophenacomys osborni – or unidentified comparable form
* †Pliosaccomys
** †Pliosaccomys dubius – or unidentified comparable form
* †Poebrotherium
** †Poebrotherium wilsoni
* †Pogonodon
** †Pogonodon brachyops
** †Pogonodon cismontanus – type locality for species
** †Pogonodon eileenae
* †Problastomeryx
** †Problastomeryx primus
* †Procamelus
** †Procamelus grandis
* †Procastoroides
** †Procastoroides sweeti – or unidentified comparable form
* †Procrax – type locality for genus
** †Procrax brevipes – type locality for species
* †Prodipodomys
** †Prodipodomys idahoensis
* †Prodipoides
** †Prodipoides dividerus
* †Proharrymys
** †Proharrymys fedti – type locality for species
** †Proharrymys schlaikjeri
** †Proharrymys wahlerti
* †Proheteromys
** †Proheteromys gremmelsi – type locality for species
** †Proheteromys ironcloudi – type locality for species
** †Proheteromys matthewi – type locality for species
* †Promartes
** †Promartes gemmarosae
** †Promartes lepidus – type locality for species
** †Promartes olcotti
* Restoration of the Miocene hippopotamus-like oreodont Promerycochoerus both onshore and in the water. Robert Bruce Horsfall (1913). †Promerycochoerus
** †Promerycochoerus carrikeri
** †Promerycochoerus superbus
* †Promylagaulus
** †Promylagaulus riggsi – type locality for species
* †Proscalops
** †Proscalops evelynae – type locality for species
** †Proscalops secundus
** †Proscalops tertius
* †Prosciurus
** †Prosciurus dawsonae
* †Prosthennops
** †Prosthennops niobrarensis – or unidentified comparable form
* †Protapirus
** †Protapirus obliquidens – type locality for species
** †Protapirus simplex – type locality for species
* †Proterix
** †Proterix bicuspis
** †Proterix loomisi
* Life restoration of a female (left) and male of the Oligocene-Miocene even-toed ungulate Protoceras. Charles R. Knight (1896). †Protoceras
** †Protoceras celer
** †Protoceras skinneri – type locality for species
* †Protohippus
** †Protohippus supremus – type locality for species
* †Protolabis
** †Protolabis heterodontus
* †Protospermophilus
* Pseudacris
** †Pseudacris clarki – or unidentified comparable form
* †Pseudaelurus
* †Pseudhipparion
** †Pseudhipparion gratum
** †Pseudhipparion retrusum
* †Pseudoblastomeryx
** †Pseudoblastomeryx advena
* †Pseudograptemys
** †Pseudograptemys inornata – type locality for species
* Fossilized skeleton of the Eocene protoceratid mammal Pseudoprotoceras †Pseudoprotoceras
** †Pseudoprotoceras longinaris
** †Pseudoprotoceras minor
* †Pseudotheridomys
* †Pseudotrimylus
** †Pseudotrimylus dakotensis
* †Pterogaulus
* †Pterygoboa – type locality for genus
** †Pterygoboa miocenica – type locality for species

## Q

* A
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* †Quadrodens
** †Quadrodens wilsoni – type locality for species
* Querquedula
** †Querquedula integra – type locality for species

## R

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* †Rana
** A living Rana catesbeiana (sometimes Lithobates catesbeianus), or American bullfrog †Rana catesbeiana
** †Rana pipiens
* Reithrodontomys
** †Reithrodontomys moorei
* Rhineura
** †Rhineura hatcherii – type locality for species
** †Rhineura sepultura – type locality for species
* †Russellagus
** †Russellagus vonhofi – or unidentified comparable form

## S

* A
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* Salvadora
** †Salvadora paleolineata
* †Sanctimus
** †Sanctimus stuartae – type locality for species
* †Scalopoides
** †Scalopoides isodens – or unidentified comparable form
* Scaphiopus
* †Scaptohyus
** †Scaptohyus altidens – type locality for species
* †Schaubeumys
** †Schaubeumys clivosus
** †Schaubeumys galbreathi
** †Schaubeumys grangeri – type locality for species
* †Schizodontomys
** †Schizodontomys harkseni
* †Scottimus
** †Scottimus exiguus
** †Scottimus lophatus
* †Semotelus – tentative report
* †Sespia
** †Sespia nitida – type locality for species
* †Sinclairella
** †Sinclairella dakotensis
* Sorex
** †Sorex cinereus
* Spea
** †Spea neuter – type locality for species
* Spermophilus
* Mounted fossilized skeleton of the Pliocene-Pleistocene elephant relative Stegomastodon †Stegomastodon
** †Stegomastodon mirificus
* †Steneofiber
** †Steneofiber fossor
** †Steneofiber gradatus
* †Stibarus
** †Stibarus obtusilobus
** †Stibarus quadricuspis
* Strix
** †Strix dakota – type locality for species
* Mounted fossilized skeleton of the Eocene-Oligocene tortoise Stylemys †Stylemys
** †Stylemys nebrascensis
* †Subhyracodon
** †Subhyracodon mitis
** †Subhyracodon occidentalis
* †Sunkahetanka
** †Sunkahetanka geringensis
* Sylvilagus
** †Sylvilagus floridanus

## T

* A
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* Tapirus
* Restoration of the Miocene-Pliocene rhinoceros Teleoceras †Teleoceras
** †Teleoceras major
* †Teleodus – type locality for genus
** †Teleodus avus – type locality for species
* †Temperocastor
** †Temperocastor valentinensis
* †Tenudomys
** †Tenudomys macdonaldi – type locality for species
* Thamnophis
** †Thamnophis sirtalis
* †Thinohyus
* Thomomys
* †Tisisthenes
** †Tisisthenes parvus
* Mounted fossilized skeleton of the Miocene-Pleistocene camel Titanotylopus †Titanotylopus
* †Trigenicus
** †Trigenicus profectus
* †Trigonias
** †Trigonias osborni
** †Trigonias wellsi – type locality for species
* †Trilaccogaulus
** †Trilaccogaulus ovatus
* †Triletes
** †Triletes velus – type locality for species
* †Tylionomys
** †Tylionomys woodi
* Tympanuchus
** †Tympanuchus stirtoni – type locality for species
* †Tyrannomys
** †Tyrannomys harkseni

## U

* A
* B
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* †Ursavus
* †Ustatochoerus
** †Ustatochoerus medius

## W

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* Y
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* †Wilsoneumys – tentative report
** †Wilsoneumys planidens
* †Wilsonosorex
** †Wilsonosorex bateslandensis
* †Woodoceras – type locality for genus
** †Woodoceras brachyops – type locality for species

## X

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* †Xenochelys
** †Xenochelys formosa – type locality for species

## Z

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* A living Zapus jumping mouse Zapus
** †Zapus sykesae
* Zelkova
** †Zelkova planeroides