# List of the Mesozoic life of Utah

This list of the Mesozoic life of Utah contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Utah and are between 252.17 and 66 million years of age.

## A

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* †Abrekopsis
** †Abrekopsis depresispirus – type locality for species
* †Abydosaurus – type locality for genus
** †Abydosaurus mcintoshi – type locality for species
* †Aclistochara
** †Aclistochara bransoni
* Fossilized skull of the Late Cretaceous duck-billed dinosaur Acristavus †Acristavus
** †Acristavus gagslarsoni
* †Adelodelphys
** †Adelodelphys muizoni
* †Adelolophus – type locality for genus
** †Adelolophus hutchisoni – type locality for species
* †Admetopsis
* †Adocus
* †Aenigmadelphys
** †Aenigmadelphys archeri – type locality for species
* Diagram illustrating the sizes of three specimens of the Late Cretaceous long-necked dinosaur Alamosaurus, with an anachronistic human to scale †Alamosaurus
** †Alamosaurus sanjuanensis
* †Albanerpeton
** †Albanerpeton cifellii – type locality for species
** †Albanerpeton galaktion
** †Albanerpeton gracilis
** †Albanerpeton nexuosus
* †Allocrioceras
** †Allocrioceras annulatum
* Life restoration of the Late Jurassic theropod dinosaur Allosaurus †Allosaurus
** †Allosaurus fragilis
** †Allosaurus jimmadseni – type locality for species
* †Alphadon
** †Alphadon attaragos
** †Alphadon eatoni – type locality for species
** †Alphadon halleyi
** †Alphadon marshi – or unidentified comparable form
** †Alphadon sahnii
* †Alzadites
** †Alzadites incomptus
* †Amberleya – tentative report
* †Amblotherium
** †Amblotherium gracilis
* †Ameribaatar – type locality for genus
** †Ameribaatar zofiae – type locality for species
* †Ameribataar
** †Ameribataar zofiae
* Amia
* †Ampezzopleura
** †Ampezzopleura rugosa – type locality for species
* †Amplovalvata
* †Anaflemingites
** †Anaflemingites silberlingi – or unidentified related form
* †Anasibirites
** †Anasibirites angulosus
** †Anasibirites bastini
** †Anasibirites hircinus
** †Anasibirites kingianus
** †Anasibirites mojsisovicsi
** †Anasibirites multiformis
** †Anasibirites tenuistriatus
* †Anawasatchites
* †Anchisauripus
** †Anchisauripus sillimani
* †Anchistodelphys – type locality for genus
** †Anchistodelphys archibaldi – type locality for species
** †Anchistodelphys delicatus – type locality for species
* †Anchura
* †Anemia
** †Anemia dakotensis
** †Anemia dicksoniana
** †Anemia fremontii
* Mounted fossilized skeleton of the Cretaceous armored dinosaur Animantarx †Animantarx – type locality for genus
** †Animantarx ramaljonesi – type locality for species
* †Anisomyon
* Anomia
* †Anomoepus
* †Apatopus
** †Apatopus lineatus
* †Apatosaurus
** †Apatosaurus louisae – type locality for species
* †Apistodon – report made of unidentified related form or using admittedly obsolete nomenclature
** †Apistodon exiguus – or unidentified related form
* †Aquiladelphis – tentative report
** †Aquiladelphis laurae – type locality for species
* †Araeodon
** †Araeodon intermissus
* †Araucariacites
** †Araucariacites australis
** †Araucariacites fissus
* Petrified trunk segments of the Permian-Late Triassic conifer tree Araucarioxylon arizonicum †Araucarioxylon
* †Arcomya
* †Arctoceras
** †Arctoceras tuberculatum
* †Arctoprionites
** †Arctoprionites resseri
* †Arvinachelys – type locality for genus
** †Arvinachelys goldeni – type locality for species
* †Aspenites
** †Aspenites acutus
* Astarte
** †Astarte livingstonensis
** †Astarte meeki
* Fossil of the Ordovician-Modern sea star trace fossil ichnogenus Asteriacites Asteriacites
** †Asteriacites lumbricalis
* †Astralopteris
** †Astralopteris coloradica
* †Astroconodon
** †Astroconodon delicatus – type locality for species
* †Atreipus
** †Atreipus milfordensis
* †Aublysodon – tentative report
* †Aucellina
* †Austrotindaria
** †Austrotindaria canalensis
** †Austrotindaria svalbardensis
* †Avitotherium – type locality for genus
** †Avitotherium utahensis – type locality for species

## B

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* †Baena
* †Baibisha – or unidentified comparable form
* †Bajarunia
** †Bajarunia confusionensis – type locality for species
* †Bakevellia
** †Bakevellia costata
** †Bakevellia costatus – or unidentified comparable form
** †Bakevellia exporrecta
** †Bakevellia silberlingi – type locality for species
* Life reconstruction of an individual rearing up to defend itself against a pair of Allosaurus †Barosaurus
** †Barosaurus lentus
* †Basilemys
* †Batrachopus
* †Battenizyga
** †Battenizyga eotriassica – type locality for species
* †Bernissartia
* †Bicuspidon – type locality for genus
** †Bicuspidon numerosus – type locality for species
** †Bicuspidon smikros – type locality for species
* †Borissiakoceras
* †Bothriagenys – type locality for genus
** †Bothriagenys mysterion – type locality for species
* Life restoration of the Late Cretaceous plesiosaur Brachauchenius hunting a hesperornithiform bird †Brachauchenius
** †Brachauchenius lucasi
* †Brachiosaurus
* †Brachychirotherium
** †Brachychirotherium thuringiacum
* †Brachyphyllum
** †Brachyphyllum crassicaule
* †Brasilichnium
* †Brontomerus – type locality for genus
** †Brontomerus mcintoshi – type locality for species
* †Brontopodus
* Life restoration of a herd of the Late Jurassic sauropod dinosaur Brontosaurus †Brontosaurus
** †Brontosaurus parvus
* †Brownichnus
** †Brownichnus favosites – type locality for species
* †Bryceomys
** †Bryceomys fumosus – type locality for species
** †Bryceomys hadrosus
** †Bryceomys intermedius – type locality for species

## C

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* †Callialasporites
** †Callialasporites segmentatus
** †Callialasporites turbatus
* Callistina
** †Callistina alta – or unidentified related form
* †Calycoceras
** †Calycoceras naviculare
* Life restoration of a herd of the Late Jurassic sauropod dinosaur Camarasaurus †Camarasaurus – type locality for genus
** †Camarasaurus lentus – type locality for species
* Campeloma
* †Camptonectes
** †Camptonectes platessiformis
** †Camptonectes stygius
* †Camptosaurus
** †Camptosaurus dispar
* †Cantioscyllium – or unidentified comparable form
* †Carmelopodus – type locality for genus
** †Carmelopodus untermannorum – type locality for species
* †Carycorbula
** †Carycorbula nematophora
* †Cassiope
** †Cassiope utahensis
* †Cedaromys
** †Cedaromys bestia – type locality for species
** †Cedaromys hutchisoni – or unidentified comparable form
** †Cedaromys minimus – type locality for species
** †Cedaromys parvus – type locality for species
* †Cedarosaurus – type locality for genus
** †Cedarosaurus weiskopfae – type locality for species
* †Cedarpelta – type locality for genus
** †Cedarpelta bilbeyhallorum – type locality for species
* †Cedrorestes – type locality for genus
** †Cedrorestes crichtoni – type locality for species
* †Cedroxylon
* †Ceratodus
* Restoration of the Late Jurassic ceratosaur Ceratosaurus †Ceratosaurus
** †Ceratosaurus nasicornis
** †Ceratosaurus dentisulcatus – type locality for species
* †Cercomya
** †Cercomya punctata
* †Cerebropollenites
** †Cerebropollenites macroverruesus
* Cerithiopsis
* †Chamops
** †Chamops segnis
* †Characichnos
* †Chartronella
** †Chartronella pagina – type locality for species
** †Chartronella unicostata – type locality for species
* Restoration of the Late Triassic coelacanth fish Chinlea †Chinlea – type locality for genus
** †Chinlea sorenseni – type locality for species
* †Chirotherium
** †Chirotherium rex – or unidentified comparable form
* Chlamys
* †Chondrites
* †Churkites
** †Churkites noblei
* †Cimexomys
** †Cimexomys antiquus – or unidentified comparable form
** †Cimexomys gregoryi – type locality for species
* †Cimolodon
** †Cimolodon electus
** †Cimolodon nitidus – or unidentified comparable form
** †Cimolodon similis
** †Cimolodon wardi – type locality for species
* Life restoration of the face of the Late Cretaceous multituberculate mammal Cimolomys †Cimolomys
** †Cimolomys clarki
** †Cimolomys milliensis – type locality for species
* †Cionichthys – type locality for genus
** †Cionichthys dunklei – type locality for species
* Cladophlebis
** †Cladophlebis constricta
** †Cladophlebis parva
* †Claraia
* †Cnodontosaurus – type locality for genus
** †Cnodontosaurus suchockii – type locality for species
* †Coelophysis – tentative report
* †Coelostylina
** †Coelostylina angulifera – or unidentified comparable form
** †Coelostylina costata – type locality for species
** †Coelostylina virginensis – type locality for species
* Life restoration of the Late Jurassic primmitive tyrannosaur Coelurus †Coelurus
** †Coelurus fragilis
* †Compsemys
* †Confusionella
** †Confusionella loczyi
* †Coniophis
* †Coniopteris
** †Coniopteris hymenophylloides
* †Contogenys
** †Contogenys sloani – or unidentified comparable form
* Corbula
* †Cordillerites
** †Cordillerites compressus
* †Corviconodon
** †Corviconodon utahensis – type locality for species
* Cossmannea
** †Cossmannea imayi
** †Cossmannea imlayi
** †Cossmannea kanabensis
* †Costatoria
* †Cowboyiceras – type locality for genus
** †Cowboyiceras farwestense – type locality for species
* †Cretorectolobus
* †Crittendenia
* †Ctenacodon
* †Cteniogenys
* †Ctenostreon
** †Ctenostreon gikshanensis – or unidentified comparable form
* Cucullaea
** †Cucullaea haguei
* †Culicolestes – type locality for genus
** †Culicolestes kielanae – type locality for species
* Fossil of the Jurassic-Cretaceous cycad relative Cycadeoidea †Cycadeoidea
** †Cycadeoidea cleavelandii
** †Cycadeoidea medullara
* Cylichna
* †Cylindrobullina
** †Cylindrobullina convexa – type locality for species
* †Cymbophora
* †Cynepteris
** †Cynepteris lasiophora
* †Cypellospongia – type locality for genus
** †Cypellospongia fimbriartis – type locality for species
* †Czekanowskia
** †Czekanowskia turneri – type locality for species

## D

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* †Dakotadens – type locality for genus
** †Dakotadens morrowi – type locality for species
** †Dakotadens pertritus – type locality for species
* †Dakotamys
** †Dakotamys malcolmi – type locality for species
* †Dakotaseps – type locality for genus
** †Dakotaseps gillettorum – type locality for species
* †Dakotasuchus
** †Dakotasuchus kingi
* †Deinonychus
* †Deinosuchus
** †Deinosuchus hatcheri
* †Denazinemys
** †Denazinemys nodosa
* Dentalium
** †Dentalium sublineatum – or unidentified related form
* Restoration of the Late Cretaceous horned dinosaur Diabloceratops †Diabloceratops – type locality for genus
** †Diabloceratops eatoni – type locality for species
* †Dicothodon – type locality for genus
** †Dicothodon cifelli
** †Dicothodon cifellii – type locality for species
** †Dicothodon moorensis – type locality for species
* †Dieneroceras
** †Dieneroceras dieneri
* †Dimekodontosaurus – type locality for genus
** †Dimekodontosaurus madseni – type locality for species
* †Dinehichnus – type locality for genus
** †Dinehichnus socialis – type locality for species
* †Dinochelys – type locality for genus
** †Dinochelys whitei – type locality for species
* †Dinophyton
** †Dinophyton spinosus
* †Dinosauropodes – type locality for genus
** †Dinosauropodes bransfordii
** †Dinosauropodes magrawii – type locality for species
** †Dinosauropodes osborni
** †Dinosauropodes wilsoni
* †Diplochilus – tentative report
* Life restoration of the Late Jurassic long-necked dinosaur Diplodocus †Diplodocus
** †Diplodocus hallorum
** †Diplodocus longus
* Discinisca – report made of unidentified related form or using admittedly obsolete nomenclature
* †Docodon
* †Doswellia
* †Drepanocheilus
** †Drepanocheilus ruidium
* †Dryolestes
** †Dryolestes priscus
* †Dryosaurus
** †Dryosaurus elderae – type locality for species
* †Dystrophaeus – type locality for genus
** †Dystrophaeus viaemalae – type locality for species

## E

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* †Elegantinia
* Elliptio
* Restoration of the Early Cretaceous-Eocene bony fish Enchodus, or the "saber-toothed herring" †Enchodus
* †Enneabatrachus
* †Entalophora
** †Entalophora stokesi
* †Entolioides
* †Entolium
* †Entradasuchus – type locality for genus
** †Entradasuchus spinosus – type locality for species
* †Eoalphadon
** †Eoalphadon clemensi – type locality for species
** †Eoalphadon lillegraveni – type locality for species
** †Eoalphadon woodburnei – type locality for species
* †Eocephalites
** †Eocephalites primus
* †Eodelphis
* †Eoginkgoites
* Illustration of a reconstructed skull and restorative portrait of the Late Cretaceous primitive duck-billed dinosaur Eolambia †Eolambia – type locality for genus
** †Eolambia caroljonesa – type locality for species
* †Eopolycotylus – type locality for genus
** †Eopolycotylus rankini – type locality for species
* †Equisetites
* †Equisetum
** †Equisetum burchardtii
** †Equisetum UD006 – informal
* †Eryma
** †Eryma jungostrix
* †Eucalyptus
** †Eucalyptus dakotensis
* †Eumorphotis
** †Eumorphotis beneckei – or unidentified comparable form
** †Eumorphotis ericius – type locality for species
** †Eumorphotis hinnitidea
** †Eumorphotis multiformis
** †Eumorphotis venetiana
** †Eumorphotis virginensis – type locality for species
* †Eunaticina
** †Eunaticina textilis
* †Euomphaloceras
* †Euspira
** †Euspira concinna
* †Euthlastus
** †Euthlastus cordiformis
* †Eutretauranosuchus
* †Evazoum
* †Exesipollenites
** †Exesipollenites tumulosus
* Fossilized shell of the Jurassic-Cretaceous foam oyster Exogyra †Exogyra
** †Exogyra acroumbonata
** †Exogyra levis
* †Exostinus – or unidentified comparable form

## F

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* †Fabrosaurus – tentative report
* Fossilized skeleton of the Early Cretaceous therizinossaur Falcarius †Falcarius – type locality for genus
** †Falcarius utahensis – type locality for species
* Ficus
** †Ficus daphnogenoides
* †Flemingites
* †Fona – type locality for genus
** †Fona herzogae – type locality for species
* †Frenelopsis
** †Frenelopsis varians
** †Frenelopsis variens

## G

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* Mounted fossilized skeletons of the Early Cretaceous armored dinosaur Gastonia †Gastonia – type locality for genus
** †Gastonia burgei – type locality for species
** †Gastonia lorriemcwhinneyae – type locality for species
* †Geltena
* †Geminiraptor
** †Geminiraptor suarezarum
* †Germanonautilus – tentative report
* †Gervillaria
** †Gervillaria montanaensis
* †Gervillia
* Gleichenia
** †Gleichenia comptoniaefolia
** †Gleichenia delicatula
* †Glirodon – type locality for genus
** †Glirodon grandis – type locality for species
* Globularia – tentative report
* †Glyptops
** †Glyptops plicatulus – type locality for species
* †Gondolella
** †Gondolella planata
* †Goniobasis – tentative report
** †Goniobasis subtortuosa
* †Goniodiscus
** †Goniodiscus smithi
* †Goniomya
** †Goniomya montanaensis
* Restoration of the Late Jurassic-Early Cretaceous crocodile relative Goniopholis †Goniopholis
* †Grallator
** †Grallator cursorius
* †Grammatodon
** †Grammatodon haguei
* †Gryphaea
** †Gryphaea planoconvexa
* †Gryphaeostrea
* Mounted fossilized skeleton of the Late Cretaceous duck-billed dinosaur Gryposaurus †Gryposaurus
** †Gryposaurus monumentensis – type locality for species
* †Guodunites
** †Guodunites hooveri
* †Gwyneddichnium
* †Gypsonictops

## H

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* Life restoration of the Late Cretaceous oviraptorosaur Hagryphus †Hagryphus – type locality for genus
** †Hagryphus giganteus – type locality for species
* †Hamulus – tentative report
** †Hamulus subquadratus
* †Hanielites
* †Harmodontosaurus – type locality for genus
** †Harmodontosaurus emeryensis – type locality for species
* †Hausmania
** †Hausmania rigida
* †Hedenstroemia
** †Hedenstroemia kossmati
* Hemiaster
** †Hemiaster humphreysanus
* †Hemicalypterus – type locality for genus
** †Hemicalypterus weiri – type locality for species
* †Heminajas – tentative report
** †Heminajas balatonis – or unidentified comparable form
* †Hemiprionites
** †Hemiprionites typus
* Life restoration of the Early Cretaceous Iguanodon relative Hippodraco †Hippodraco – type locality for genus
** †Hippodraco scutodens – type locality for species
* †Hispanosauropus
* †Hoernesia
* †Holocrinus
** †Holocrinus dubius – tentative report
** †Holocrinus smithi
* †Homalopoma
** †Homalopoma sinbadensis – type locality for species
* †Homomya
* †Hoplitosaurus – or unidentified comparable form
* †Hoplosuchus – type locality for genus
** †Hoplosuchus kayi – type locality for species
* Restoration of two of the Permian-Late Cretaceous cartilaginous fish Hybodus †Hybodus
* †Hyporosopora
** †Hyporosopora nielsoni – type locality for species

## I

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* †Iani – type locality for genus
** †Iani smithi – type locality for species
* †Icacinoxylon
** †Icacinoxylon pittiense – type locality for species
* †Idahocolumbites
** †Idahocolumbites cheneyi
* Life restoration of the Early Cretaceous Iguanodon relative Iguanacolossus †Iguanacolossus – type locality for genus
** †Iguanacolossus fortis – type locality for species
* †Iguanodon
** †Iguanodon ottingeri – type locality for species
* Ilex
** †Ilex serrata
* Fossilized shell of the Early Jurassic-Late Cretaceous marine bivalve Inoceramus with a human indicating its size †Inoceramus
** †Inoceramus albertensis – or unidentified comparable form
** †Inoceramus flavus
** †Inoceramus gilberti
** †Inoceramus koeneni
** †Inoceramus pictus
** †Inoceramus tenuistriatus – tentative report
** †Inoceramus undabundus
* †Inyoites
** †Inyoites beaverensis – type locality for species
** †Inyoites oweni
* †Iqualadelphis
** †Iqualadelphis lactea
* †Iridotriton – type locality for genus
** †Iridotriton hechti – type locality for species
* †Ischyrhiza – or unidentified comparable form
* Isocrinus
** †Isocrinus nicoleti
* Fossilized shell of the Permian-modern marine bivalve Isognomon Isognomon
** †Isognomon perplana – or unidentified comparable form
* †Iugomortiferum – type locality for genus
** †Iugomortiferum thoringtoni – type locality for species

## J

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* †Janumys – type locality for genus
** †Janumys erebos – type locality for species
** †Janumys erebros
* †Jeanbesseiceras
** †Jeanbesseiceras jacksoni
* †Jugulator
** †Jugulator amplissimus
* †Juvenites
** †Juvenites spathi – or unidentified related form
** †Juvenites thermarum – or unidentified comparable form

## K

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* Fossilized shells of the Jurassic brachiopod Kallirhynchia †Kallirhynchia
** †Kallirhynchia myrina – type locality for species
* †Kamerunoceras
* †Kashmirites
** †Kashmirites confusionensis
** †Kashmirites meeki
** †Kashmirites nivalis
** †Kashmirites perrini
** †Kashmirites seerleyi
** †Kashmirites stepheni – type locality for species
** †Kashmirites subarmatus
** †Kashmirites utahensis – type locality for species
* †Kayentapus
* †Kokopellia – type locality for genus
** †Kokopellia juddi – type locality for species
* †Koparion – type locality for genus
** †Koparion douglassi – type locality for species
* †Koreanaornis
** †Koreanaornis hamanensis – or unidentified comparable form
* Life restoration of the Late Cretaceous horned dinosaur Kosmoceratops †Kosmoceratops – type locality for genus
** †Kosmoceratops richardsoni – type locality for species
* †Kouphichnium

## L

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* †Ladinaticella
** †Ladinaticella striatocostata
* †Lanceolites
** †Lanceolites bicarinatus
** †Lanceolites compactus
* †Lasalichthys – type locality for genus
** †Lasalichthys hillsi – type locality for species
* †Latochara
** †Latochara latitruncata
* †Laubopsis – tentative report
* †Legumen
* Fossilized skull of the Late Cretaceous alligator relative Leidyosuchus †Leidyosuchus
* †Lenticidaris – type locality for genus
** †Lenticidaris utahensis – type locality for species
* †Lepidotes
** †Lepidotes walcotti – type locality for species
* Lepisosteus
* †Leptalestes
* †Leptochamops
** †Leptochamops denticulatus
* †Leptochondria
** †Leptochondria curtocardinalis
** †Leptochondria nuetzeli – type locality for species
** †Leptochondria occidanea – type locality for species
** †Leptochondria xijinwulanensis
* Lima
* †Lingularia
** †Lingularia borealis
* †Liopistha
** †Liopistha meeki
* †Liostrea
** †Liostrea strigilecula
* †Liriophyllum
** †Liriophyllum UD012 – informal
* †Lissodus
* †Litakis
** †Litakis gilmorei
* †Lonchidion
* Lopha
** †Lopha engelmanni – or unidentified related form
* Lucina
* †Lyosoma
** †Lyosoma enoda
** †Lyosoma powelli
* Life restoration of the Late Cretaceous tyrannosaur Lythronax †Lythronax – type locality for genus
** †Lythronax argestes – type locality for species

## M

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* Life restoration of the Late Cretaceous horned dinosaur Machairoceratops †Machairoceratops – type locality for genus
** †Machairoceratops cronusi – type locality for species
* †Macroelongatoolithus
** †Macroelongatoolithus carlylei – type locality for species
* †Mactromya – tentative report
* †Magadiceramus
** †Magadiceramus crenelatus
** †Magadiceramus crenistriatus
** †Magadiceramus soukupi
* Magnolia
** †Magnolia boulayana
* †Mammites
** †Mammites nodosoides
* Life restoration of the Late Jurassic megalosaur Marshosaurus †Marshosaurus – type locality for genus
** †Marshosaurus bicentesimus – type locality for species
* †Martharaptor – type locality for genus
** †Martharaptor greenriverensis – type locality for species
* †Matonidium
** †Matonidium brownii
** †Matonidium lancipinnulum
* †Meekoceras
** †Meekoceras davisi
** †Meekoceras gracilitatis
** †Meekoceras millardense – type locality for species
** †Meekoceras olivieri – type locality for species
* †Megalosauripus
* †Megasphaeroceras
** †Megasphaeroceras rotundum – or unidentified comparable form
* †Melvius
** †Melvius chauliodous – or unidentified comparable form
* Fossilized skull of the Late Cretaceous multituberculate mammal Meniscoessus †Meniscoessus
** †Meniscoessus intermedius
* †Meniscognathus
** †Meniscognathus altmani – or unidentified comparable form
** †Meniscognathus molybrochoros – type locality for species
* †Mesembrioxylon
** †Mesembrioxylon stokesi
** †Mesembrioxylon stokesii
* †Mesembryoxylon
* †Mesodma
** †Mesodma formosa – or unidentified comparable form
** †Mesodma hensleighi – or unidentified comparable form
** †Mesodma minor – or unidentified comparable form
** †Mesodma thompsoni – or unidentified comparable form
* †Mesostoma
* †Metoicoceras
** †Metoicoceras geslinianum
* †Microcachrydites
* †Microconchus
** †Microconchus utahensis
* †Microeciella
** †Microeciella duoflavina
** †Microeciella pollostos – type locality for species
* †Minersvillites – type locality for genus
** †Minersvillites farai – type locality for species
* †Miocidaris
** †Miocidaris utahensis
* Mounted fossilized skeletons of the Early Cretaceous long-necked dinosaur Moabosaurus †Moabosaurus – type locality for genus
** †Moabosaurus utahensis – type locality for species
* Modiolus
** †Modiolus isonemus
** †Modiolus subimbricatus
* †Monanthesia
* †Monocnemodon – type locality for genus
** †Monocnemodon syphakos – type locality for species
* †Moros – type locality for genus
** †Moros intrepidus – type locality for species
* †Myalina
* †Myledaphus
** †Myledaphus bipartitus
* †Myoconcha
** †Myoconcha plana – or unidentified comparable form
* †Myopholas
** †Myopholas hardyi
* Fossilized shell of the Jurassic-Cretaceous marine bivalve Myophorella †Myophorella
** †Myophorella livinigstonensis
** †Myophorella monatanaensis
** †Myophorella yellowstonensis
* †Myophoria
* †Mytiloides
** †Mytiloides submytiloides – or unidentified related form
* †Mytilus
** †Mytilus whitei – or unidentified comparable form

## N

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Naomichelys
* Known material diagram of the Late Cretaceous horned dinosaur Nasutoceratops †Nasutoceratops – type locality for genus
** †Nasutoceratops titusi – type locality for species
* †Naticopsis
** †Naticopsis depressispira
** †Naticopsis fenestravella – type locality for species
** †Naticopsis utahensis – type locality for species
* †Natiria
** †Natiria aequicostata – type locality for species
** †Natiria costata – or unidentified comparable form
* †Nedcolbertia – type locality for genus
** †Nedcolbertia justinhoffmanni – type locality for species
* †Nemodon
* †Neocardioceras
** †Neocardioceras juddii
* †Neocrioceras
* †Neoschizodus
** †Neoschizodus laevigatus
** †Neoschizodus orbicularis – or unidentified comparable form
** †Neoschizodus praeorbicularis
** †Neoschizodus thaynesianus – type locality for species
* †Neridomus – tentative report
* Fossilized shell of the Jurassic-Cretaceous sea snail Nerinea †Nerinea – tentative report
* †Neritaria
** †Neritaria costata – type locality for species
* Neritina
** †Neritina phaseolaris
* †Neurankylus
* †Nezpercius
** †Nezpercius dodsoni
* †Nilsonia
** †Nilsonia lewisii – type locality for species
* †Nilssoniopteris
* †Nododelphinula – tentative report
* †Normannites – tentative report
** †Normannites crickmayi – or unidentified related form
* Mounted fossilized skeleton of the Late Cretaceous Nothronychus †Nothronychus
** †Nothronychus graffami – type locality for species
* Nucula
* Nuculana
** †Nuculana mutuata – or unidentified comparable form
* †Nymphalucina
** †Nymphalucina linearia – or unidentified related form

## O

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Obnixia – type locality for genus
** †Obnixia thaynesiana
* †Odaxosaurus
** †Odaxosaurus piger – or unidentified comparable form
** †Odaxosaurus priscus
** †Odaxosaurus roosevelti – type locality for species
* †Omphaloptycha
** †Omphaloptycha hormolira – type locality for species
* †Omphaloptychia
** †Omphaloptychia laevisphaera – type locality for species
* Oncousoecia – tentative report
* †Ooliticia – tentative report
* †Ophioglypha
** †Ophioglypha utahensis – type locality for species
* †Opisthias
* †Ornithomimus
* †Osteocallis
** †Osteocallis mandibulus
* Ostrea
** †Ostrea occidentalis
** †Ostrea strigulecula
* Mounted fossilized skeleton of the Late Jurassic herbivorous dinosaur Othnielosaurus †Othnielosaurus
** †Othnielosaurus consors
* †Otozoum
* †Ovaloolithus
** †Ovaloolithus tenuisus – type locality for species
** †Ovaloolithus utahensis – type locality for species
* †Owenites
** †Owenites carpenteri
** †Owenites koeneni

## P

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Pachyomphalus
** †Pachyomphalus americanus – type locality for species
* Fossilized foliage of the Carboniferous-Late Cretaceous plant Pagiophyllum †Pagiophyllum
* †Paiutemys – type locality for genus
** †Paiutemys tibert – type locality for species
* †Palaeophycus – or unidentified comparable form
* †Palaeopiceoxylon
** †Palaeopiceoxylon thinosu
** †Palaeopiceoxylon thinosus
* †Palaeoscincosaurus
** †Palaeoscincosaurus pharkidodon – type locality for species
* †Paleoaster
** †Paleoaster inquirenda
* †Palmulasaurus – type locality for genus
** †Palmulasaurus quadratus – type locality for species
* †Parachondroceras
** †Parachondroceras andrewsi
** †Parachondroceras filicostatum – or unidentified comparable form
* †Paracimexomys
** †Paracimexomys judithae – or unidentified comparable form
** †Paracimexomys magnus
** †Paracimexomys perplexus – type locality for species
** †Paracimexomys priscus – or unidentified comparable form
** †Paracimexomys robisoni – type locality for species
* †Paraglyphanodon – type locality for genus
** †Paraglyphanodon gazini – type locality for species
** †Paraglyphanodon utahensis – type locality for species
* †Parallelodon – tentative report
** †Parallelodon beyrichii – or unidentified related form
* †Paramacellodus
** †Paramacellodus oweni – or unidentified comparable form
* †Paranyctoides
* †Paraphyllanthoxylon
** †Paraphyllanthoxylon utahense
* †Parasaniwa
** †Parasaniwa cynochoros – type locality for species
** †Parasaniwa wyomingensis – or unidentified comparable form
* Life restoration of the Late Cretaceous duck-billed dinosaur Parasaurolophus being preyed upon by the tyrannosaur Teratophoneus †Parasaurolophus
** †Parasaurolophus cyrtocristatus
* †Pariadens
** †Pariadens kirklandi – type locality for species
** †Pariadens mckennai – type locality for species
* †Parmicorbula
* †Paronychodon – or unidentified comparable form
* †Parotosuchus
** †Parotosuchus nov. spec. – informal
* †Parussuria
** †Parussuria compressa
* †Patulopora
** †Patulopora cutleri
* †Paullia
* †Pediomys – report made of unidentified related form or using admittedly obsolete nomenclature
* †Pegmavalvula
** †Pegmavalvula triassica
* †Pelecypodichnus
* †Peloroplites – type locality for genus
** †Peloroplites cedrimontanus – type locality for species
* †Peneteius – type locality for genus
** †Peneteius saueri – type locality for species
* †Pentasauropus
* †Periallus
** †Periallus woodsidensis
* †Perissoptera
* †Permophorus
** †Permophorus bregeri – or unidentified comparable form
** †Permophorus triassicus
* †Pernopecten
* †Phelopteria
** †Phelopteria minuta – or unidentified comparable form
* †Phlebopteris
* Fossilized shell of the Early Triassic-Pliocene marine bivalve Pholadomya Pholadomya
** †Pholadomya inaequiplicata
** †Pholadomya kingi
* †Piarorhynchella
** †Piarorhynchella triassica
** †Piarorhynchella triassicus
* †Picopsis
* †Pinacosuchus – type locality for genus
** †Pinacosuchus mantiensis – type locality for species
* Pinna
** †Pinna kingi
* †Pistia – report made of unidentified related form or using admittedly obsolete nomenclature
** †Pistia corrugata
* †Pityoxylon
* Fossilized shell of the Late Cretaceous ammonoid cephalopod Placenticeras †Placenticeras
** †Placenticeras cumminsi
* Placopsilina
* †Plagioglypta
* †Plagiostoma
** †Plagiostoma occidentalis
** †Plagiostoma ziona
* †Planicoxa – type locality for genus
** †Planicoxa venenica – type locality for species
* †Planolites
* †Plataninium
* †Plesiopinna
* †Pleuromya
** †Pleuromya musculoides – or unidentified comparable form
** †Pleuromya prima – type locality for species
** †Pleuromya subcompressa
* †Pleuronautilus
* †Pleuronectites
* Pleurotomaria – tentative report
* Plicatula
** †Plicatula ferryi – or unidentified comparable form
* †Podozamites
* †Polyacrodus – tentative report
* †Polyglyphanodon – type locality for genus
** †Polyglyphanodon sternbergi – type locality for species
* †Polygyrina
* Restoration of the Late Triassic crocodile relative Poposaurus with an anachronistic human to scale †Poposaurus
** †Poposaurus gracilis
* †Preflorianites
** †Preflorianites toulai
* †Preprismatoolithus
** †Preprismatoolithus coloradensis
* †Priacodon
* †Primaderma – type locality for genus
** †Primaderma nessovi – type locality for species
* †Prismatoolithus
** †Prismatoolithus jenseni – type locality for species
* †Procerithium – tentative report
* †Promathildia
** †Promathildia spirocostata – type locality for species
* †Promyalina
** †Promyalina putiatinensis
** †Promyalina spathi
* †Promysidiella
* †Pronoella
** †Pronoella cinnabarensis – or unidentified comparable form
** †Pronoella uintahensis
* †Proplacenticeras
** †Proplacenticeras stantoni
* †Prorokia
** †Prorokia fontenellensis
* †Protalphadon
* †Protocardia
* †Protogusarella
** †Protogusarella smithi
* †Protolambda
** †Protolambda hatcheri - North Horn Formation
* †Protopis
** †Protopis waageni – or unidentified related form
* †Protovirgularia
* †Psalandon – tentative report
* †Pseudaspidoceras
* †Pseudocalycoceras
* †Pseudocorbula
* †Pseudohypolophus
* Fossilized shell of a Pseudomelania sea snail †Pseudomelania
* †Pseudomyoconcha – tentative report
* †Pseudoptera
* †Pseudosageceras
** †Pseudosageceras multilobatum
* †Pseudosaurillus – or unidentified comparable form
* †Pseudotetrasauropus
* †Pseudotritonium
** †Pseudotritonium sciaphosterum – type locality for species
* †Psilomya
** †Psilomya concentrica – or unidentified related form
** †Psilomya elongata – or unidentified related form
* †Pteraichnus
** †Pteraichnus saltwashensis – or unidentified comparable form
** †Pteraichnus stokesi – or unidentified comparable form
* †Ptychotrigon
* Assemblage of fossilized shells of the Cretaceous-Pleistocene oyster Pycnodonte Pycnodonte
** †Pycnodonte newberryi

## Q

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Quenstedtia
** †Quenstedtia bathonica – or unidentified related form

## R

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Radioceras
** †Radioceras evolvens – or unidentified related form
* Fossilized skeleton of the Late Triassic phytosaur Redondasaurus †Redondasaurus
** †Redondasaurus gregorii
* Rhabdocolpus
** †Rhabdocolpus viriosus
* †Rhadinosteus – type locality for genus
** †Rhadinosteus parvus – type locality for species
* †Rhynchonella – report made of unidentified related form or using admittedly obsolete nomenclature
* †Rhynchosauroides
** †Rhynchosauroides schochardti
* †Rhynchostreon
** †Rhynchostreon levis
* Micrograph with magnified inset of a fossilized tooth of the Late Cretaceous theropod dinosaur Richardoestesia †Richardoestesia
** †Richardoestesia isosceles – or unidentified comparable form
* Rogerella
* †Rotodactylus
** †Rotodactylus cursorius – type locality for species

## S

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Sabalites
** †Sabalites NE008 – informal
* Salix
** †Salix newberryana
* Life restoration of the Early Cretaceous armored dinosaur Sauropelta †Sauropelta – or unidentified comparable form
* †Scalamagnus
** †Scalamagnus tropicensis – type locality for species
* †Scapherpeton
* †Schillerosaurus – type locality for genus
** †Schillerosaurus utahensis – type locality for species
* †Sciponoceras
** †Sciponoceras gracile
* †Scotiophryne
** †Scotiophryne pustulosa
* †Scoyenia
* Known material diagram of the Early Jurassic primitive long-necked dinosaur Seitaad †Seitaad – type locality for genus
** †Seitaad ruessi – type locality for species
* †Sementiconcha – type locality for genus
** †Sementiconcha recuperator – type locality for species
* †Semionotus
** †Semionotus kanabensis – type locality for species
* Serpula
** †Serpula intrica
** †Serpula large
* †Sexta
** †Sexta navicula – or unidentified related form
* Life restoration of the Late Cretaceous theropod dinosaur Siats †Siats – type locality for genus
** †Siats meekerorum – type locality for species
* †Simplicidium
* †Sinbadelphys
** †Sinbadelphys schmidti
* †Sinbadiella – type locality for genus
** †Sinbadiella pygmaea – type locality for species
* †Skolithos
* †Sohlites
** †Sohlites spinosus
* Solemya
** †Solemya obscura
* †Soleniscus
* †Spalacolestes
** †Spalacolestes cretulablatta
** †Spalacolestes inconcinnus – type locality for species
* †Spalacotheridium – type locality for genus
** †Spalacotheridium mckennai – type locality for species
** †Spalacotheridium noblei
* Fossils of the dinosaur egg oogenus Spheroolithus †Spheroolithus
* †Spheruprismatoolithus – type locality for genus
** †Spheruprismatoolithus condensis
** †Spheruprismatoolithus condensus – type locality for species
* Spirorbis – report made of unidentified related form or using admittedly obsolete nomenclature
** †Spirorbis valvata – or unidentified comparable form
* †Spongioolithus – type locality for genus
** †Spongioolithus hirschi – type locality for species
* †Squatirhina
** †Squatirhina americana
* †Stagonolepis
* †Stegopodus – type locality for genus
** †Stegopodus czerkasi – type locality for species
* Restoration of the Late Jurassic stegosaur Stegosaurus †Stegosaurus
** †Stegosaurus stenops – or unidentified comparable form
** †Stegosaurus ungulatus
* †Stellatochara
** †Stellatochara obovata
* †Stemmatoceras
** †Stemmatoceras albertense – or unidentified related form
** †Stemmatoceras arcicostum
* †Stephanoceras
** †Stephanoceras nodosum – or unidentified related form
* Life restoration of the primitive tyrannosaur Stokesosaurus †Stokesosaurus – type locality for genus
** †Stokesosaurus clevelandi – type locality for species
* Stomatopora
* †Stomohamites
* †Strobeus
** †Strobeus batteni
* †Submeekoceras
** †Submeekoceras mushbachanum
* †Symmetrocapulus – tentative report
** †Symmetrocapulus corrugatus
* †Symmetrodontoides
** †Symmetrodontoides foxi – type locality for species
** †Symmetrodontoides oligodontos – type locality for species
* †Syncyclonema
* †Synorichthys
** †Synorichthys stewarti

## T

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* Known material diagram of the Late Cretaceous troodontid Talos †Talos – type locality for genus
** †Talos sampsoni – type locality for species
* †Tancredia – tentative report
* †Tanycolagreus
** †Tanycolagreus topwilsoni
* †Teinostomopsis – tentative report
* †Tempskya
** †Tempskya jonesii – type locality for species
** †Tempskya knowltoni
** †Tempskya minor
** †Tempskya superba
** †Tempskya whiteheadi – type locality for species
* †Tenontosaurus
* Known material diagram of the Late Cretaceous tyrannosaur Teratophoneus †Teratophoneus – type locality for genus
** †Teratophoneus curriei – type locality for species
* Teredolites
** †Teredolites clavatus
* †Tethyaster
** †Tethyaster jurassicus – type locality for species
* †Tetrasauropus
* †Thalassinoides
* †Therangopodus – tentative report
* †Therangospodus – type locality for genus
** †Therangospodus pandemicus – type locality for species
* †Theretairus
* †Thescelus
** †Thescelus insiliens
* Thracia
** †Thracia weedi
* †Tirolites
** †Tirolites carniolicus – tentative report
** †Tirolites smithi – or unidentified related form
* Mounted fossilized skeleton of the Late Jurassic megalosaur Torvosaurus †Torvosaurus
* †Toxolophosaurus – or unidentified comparable form
* †Trachodon
* †Torosaurus
** †Torosaurus utahensis
* †Triconolestes – type locality for genus
** †Triconolestes curvicuspis – type locality for species
* †Trigonia
** †Trigonia americana
** †Trigonia elegantissima
** †Trigonia montanaensis
* †Trigonodus
** †Trigonodus orientalis – or unidentified comparable form
** †Trigonodus sandbergeri – or unidentified comparable form
** †Trigonodus sandbergi – or unidentified comparable form
* Fossilized skeleton of the Late Cretaceous polycotylid plesiosaur Trinacromerum †Trinacromerum
** †Trinacromerum bentonianum – tentative report
* †Tripennaculus – type locality for genus
** †Tripennaculus eatoni – type locality for species
* †Trisauropodiscus
** †Trisauropodiscus moabensis – type locality for species
* Trochocyathus
* †Trochosmilia
** †Trochosmilia moorei – type locality for species
* †Tulotomops
** †Tulotomops laevibasalis
* †Turgidodon – type locality for genus
** †Turgidodon lillegraveni – type locality for species
** †Turgidodon madseni – type locality for species
** †Turgidodon russelli – or unidentified comparable form
* Turritella
** †Turritella whitei
* †Tylostoma – tentative report
* Fossil of the Late Cretaceous tyrannosaur footprint ichnogenus Tyrannosauripus †Tyrannosauripus – type locality for genus
** †Tyrannosauripus petersoni – type locality for species
* †Tyrannosaurus

## U

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* †Undichnia
* †Unicardium
* †Unionites
** †Unionites borealis – or unidentified comparable form
** †Unionites fassaensis
* †Ussurites
** †Ussurites hosei
* †Utahceratops – type locality for genus
** †Utahceratops gettyi – type locality for species
* †Utahgenys – type locality for genus
** †Utahgenys antongai – type locality for species
** †Utahgenys evansi – type locality for species
* Diagram illustrating the Early Cretaceous dromaeosaurid ("raptor") Utahraptor with an anachronistic human to scale †Utahraptor – type locality for genus
** †Utahraptor ostrommaysi – type locality for species
* †Uteodon – type locality for genus
** †Uteodon aphanoecetes – type locality for species

## V

* A
* B
* C
* D
* E
* F
* G
* H
* I
* J
* K
* L
* M
* N
* O
* P
* Q
* R
* S
* T
* U
* V
* W
* X
* Y
* Z
* Valvata
* Life restoration of the Late Triassic reptile Vancleavea †Vancleavea
** †Vancleavea campi
* †Varalphadon – type locality for genus
** †Varalphadon crebreforme – type locality for species
** †Varalphadon wahweapensis – type locality for species
* †Vaugonia
** †Vaugonia conradi
** †Vaugonia utahensis
* †Venenosaurus – type locality for genus
** †Venenosaurus dicrocei – type locality for species
* †Vercherites
** †Vercherites undulatus – type locality for species
* †Vex
* Shell of a Viviparus freshwater snail Viviparus

## W

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* †Wailiceras
** †Wailiceras aemulus – or unidentified comparable form
* †Wasatchites
** †Wasatchites perrini
* †Webbsaurus – type locality for genus
** †Webbsaurus lofgreni – type locality for species
* †Worthenia
** †Worthenia windowblindensis – type locality for species
* †Wortheniella
** †Wortheniella canalifera – or unidentified comparable form
* †Worthoceras
* †Wyomingites
** †Wyomingites aplanatus – or unidentified comparable form

## X

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* †Xenoceltites
** †Xenoceltites cordilleranus
** †Xenoceltites subevolutus
* †Xiaoqiaoceras – tentative report
** †Xiaoqiaoceras americanum – type locality for species

## Y

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* Life restoration of the Early Cretaceous dromaeosaurid ("raptor") Yurgovuchia †Yurgovuchia – type locality for genus
** †Yurgovuchia doellingi – type locality for species

## Z

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* Fossil of the Early Triassic-Eocene cycad-like frond Zamites †Zamites
** †Zamites powelli
** †Zamites tidwellii – type locality for species
* †Zygiocuspis – type locality for genus
** †Zygiocuspis goldingi – type locality for species
* †Zygopleura
** †Zygopleura haasi – type locality for species