List of the Mesozoic life of Arizona

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

A

 * †Acaenasuchus – type locality for genus
 * †Acaenasuchus geoffreyi – type locality for species
 * †Acallosuchus – type locality for genus
 * †Acallosuchus rectori – type locality for species
 * Douvilleiceratidae - Acanthohoplites hannoverensis.JPG †[[Acanthohoplites]]
 * †Acanthohoplites berkeyi
 * †Acanthohoplites erraticus
 * †Acanthohoplites hesper
 * †Acanthohoplites impetrabilis
 * †Acanthohoplites schucherti
 * †Acanthohoplites teres
 * Acila
 * †Acila schencki
 * Acirsa
 * †Acirsa kelseyi – type locality for species
 * Acmaea
 * †Acrodus
 * †Acteon
 * †Acteon propinguis
 * †Actinastrea
 * †Adamanasuchus – type locality for genus
 * †Adamanasuchus eisenhardtae – type locality for species
 * †Admetopsis
 * †Admetopsis subfusiformis
 * †Adocus
 * Allocrioceras pariense.jpg †[[Allocrioceras]]
 * †Allocrioceras annulatum
 * †Alzadites
 * †Alzadites incomptus
 * †Ambrosea
 * †Ambrosea nitida
 * †Ammorhynchus – type locality for genus
 * †Ammorhynchus navajoi – type locality for species
 * †Anaschisma – report made of unidentified related form or using admittedly obsolete nomenclature
 * †Anatimya
 * †Anatimya virgata
 * †Anchura
 * †Anchura hopii – type locality for species
 * Angistorhinus grandis.jpg †[[Angistorhinus]] – tentative report
 * †Anisoceras
 * †Anisoceras coloradoense
 * †Anisodontosaurus – type locality for genus
 * †Anisodontosaurus greeri – type locality for species
 * †Anisomyon
 * †Anisomyon spp.
 * †Anomia
 * †Anomia ponticulana
 * †Antediplodon
 * †Antediplodon dockumensis
 * †Apachesaurus
 * †Apachesaurus gregorii
 * †Apatosaurus
 * †Aphrodina
 * †Aphrodina munda – or unidentified comparable form
 * [[File:Araucarioxylon arizonicum (petrified wood) - National Museum of Natural History, United States - DSC08540.JPG|thumb|upright|Petrified trunk segments of the Permian-Late Triassic conifer tree [[Araucarioxylon arizonicum]]. This species is the state fossil of Arizona]] †Araucarioxylon
 * †Araucarioxylon arizonicum
 * †Arca
 * Arcopagia – or unidentified comparable form
 * †Arcopagia A – informal
 * Arctica
 * †Arganodus
 * †Aricycas
 * †Aricycas paulae
 * †Arizonasaurus – type locality for genus
 * †Arizonasaurus babbitti – type locality for species
 * Astarte
 * †Astarte adkinsi
 * †Australosomus – or unidentified comparable form

B

 * Baculites grandis shell.JPG †[[Baculites]]
 * †Baculites calamus
 * Barbatia
 * †Barbatia tramitensis
 * †Barrancapus
 * †Batrachopus
 * †Batrachopus deweyi
 * †Bellifusus
 * †Bellifusus gracilistriatus
 * †Bellifusus willistoni – or unidentified comparable form
 * †Beudanticeras
 * †Beudanticeras victoris
 * Boreosomus.jpg †[[Boreosomus]] – tentative report
 * †Borissiakoceras
 * †Borrissiakoceras
 * †Borrissiakoceras orbiculatum
 * Brachiodontes
 * †Brachiodontes filisculptus
 * †Brachychirotherium
 * †Brasilichnium – or unidentified comparable form
 * †Breviarca – tentative report
 * †Burroceras
 * †Burroceras clydense
 * †Burroceras transitorium

C

 * Cadulus
 * †Cadulus praetenuis
 * †Calamites
 * †Calamophylliopsis
 * †Calamophylliopsis sandbergeri
 * †Calsoyasuchus – type locality for genus
 * †Calsoyasuchus valliceps – type locality for species
 * †Calycoceras
 * †Calycoceras naviculare
 * †Calyptosuchus
 * †Calyptosuchus wellesi
 * Camposaurus arizonensis.png †[[Camposaurus]] – type locality for genus
 * †Camposaurus arizonensis – type locality for species
 * †Camptonectes
 * †Camptonectes A – informal
 * †Camptonectes B – informal
 * †Camptonectes platessa
 * †Caprina
 * †Caprinuloidea
 * †Caprinuloidea gracilis
 * Carota
 * †Carota dalli
 * Caryocorbula
 * †Caryocorbula nematophora
 * Ceratodus.jpg †[[Ceratodus (genus)|Ceratodus]]
 * †Cerithioderma
 * †Cerithioderma darcyi – type locality for species
 * †Cerithioderma occidentalis
 * Cerithiopsis
 * †Cerithiopsis sohli – type locality for species
 * Charonia – tentative report
 * †Charonia kanabense
 * †Charonia soozi – type locality for species
 * †Chatterjeea
 * †Chindesaurus – type locality for genus
 * †Chindesaurus bryansmalli – type locality for species
 * Chinlea BW.jpg †[[Chinlea]] – tentative report
 * †Chirotherium
 * †Chirotherium barthii
 * †Chirotherium rex – type locality for species
 * †Chirotherium sickleri
 * Chlamys
 * †Chlamys thompsoni
 * †Choffaticeras
 * †Choffaticeras pavillieri – or unidentified comparable form
 * †Chondrodonta
 * †Cibolaites
 * †Cibolaites molenaari
 * †Cionichthyes
 * †Cionichthys – or unidentified comparable form
 * †Coalcomana
 * †Coalcomana ramosa
 * †Coelophysis
 * SyntarsusDB.jpg †[[Coelophysis kayentakatae]] – type locality for species
 * †Collignoniceras
 * †Collignoniceras carolinum – or unidentified related form
 * †Collignoniceras woollgari
 * †Colognathus
 * †Colognathus obscurus
 * †Colombiceras – tentative report
 * †Colombiceras brumale
 * Corbula
 * †Corbula kanabensis
 * †Cosgriffius – type locality for genus
 * †Cosgriffius campi – type locality for species
 * †Craginia
 * †Craginia turriformis
 * †Craniscus
 * †Craniscus hesperius – type locality for species
 * Crassatella
 * Crassostrea gigantissima (Finch, 1824).JPG [[Crassostrea]]
 * †Crassostrea soleniscus
 * †Crosbysaurus
 * †Crosbysaurus harrisae
 * Cucullaea
 * †Cucullaea depressa
 * †Cucullaea stephensoni
 * †Cunningtoniceras
 * †Cunningtoniceras novimexicanum
 * Cuspidaria
 * †Cuspidaria alaeformis
 * †Cyclorisma
 * †Cyclorisma orbiculata
 * †Cyclothyris
 * †Cyclothyris americana – type locality for species
 * Cylichna
 * †Cylinodrotruncatum
 * †Cylinodrotruncatum spp.
 * †Cymbophora
 * †Cymbophora emmonsi
 * †Cymbophora huerfanensis
 * †Cymbophora utahensis
 * †Cyprimeria
 * †Cyprimeria cyprimeriformis

D

 * †Dakotacorbula
 * †Dakotacorbula senecta
 * †Dechellyia
 * †Dechellyia gormani – type locality for species
 * †Dentalium
 * †Deshayesites – tentative report
 * †Deshayesites butleri
 * †Desmatochelys
 * †Desmatochelys lowi
 * †Desmatosuchus
 * †Desmatosuchus haplocerus
 * †Desmatosuchus spurensis
 * †Dilophosauripus – type locality for genus
 * †Dilophosauripus williamsi – type locality for species
 * Dilophosaurus in bird-like resting pose.jpg †[[Dilophosaurus]]
 * †Dilophosaurus wetherilli – type locality for species
 * †Dinnebitodon – type locality for genus
 * †Dinnebitodon amarali – type locality for species
 * †Dinnetherium – type locality for genus
 * †Dinnetherium nezorum – type locality for species
 * Discinisca
 * †Dolicholatirus – tentative report
 * †Drepanocheilus
 * †Drepanocheilus ruidium
 * †Drepanochilus
 * †Drepanochilus ruidium
 * Dromomeron BW.jpg †[[Dromomeron]]
 * †Dromomeron gregorii
 * †Dufrenoyia
 * †Dufrenoyia compitalis
 * †Dufrenoyia joserita
 * †Dufrenoyia justinae

E

 * †Edentosuchus – tentative report
 * †Edentosuchus undescribed species – informal
 * †Edentosuchus undescribed species 1 – informal
 * †Edentosuchus undescribed species 2 – informal
 * Elliptio
 * †Entolium
 * †Entolium gregarium
 * †Eoacteon – tentative report
 * †Eocaecilia – type locality for genus
 * †Eocaecilia micropodia – type locality for species
 * Eocyclotosaurus wellesi1DB.jpg †[[Eocyclotosaurus]]
 * †Eocyclotosaurus wellesi – type locality for species
 * †Eopneumatosuchus – type locality for genus
 * †Eopneumatosuchus colberti – type locality for species
 * †Eucalycoceras
 * †Eucalycoceras pentagonum
 * †Eulima – tentative report
 * †Eulima funicula
 * †Eunaticina
 * †Eunaticina textilis
 * †Euomphaloceras
 * †Euomphaloceras irregulare
 * †Euomphaloceras septemseriatum
 * †Euspira
 * †Euspira concinna
 * †Euspira stantoni – type locality for species
 * †Exogyra
 * †Exogyra acroumbonata
 * †Exogyra lancha
 * †Exogyra levis
 * †Exogyra olisiponensis

F

 * Fagesia spheroidalis.jpg †[[Fagesia]]
 * †Fagesia catinus
 * †Felixigyra
 * †Flemingostrea
 * †Flemingostrea prudentia
 * †Fulpia
 * †Fulpia pinguis

G

 * †Gemmarcula
 * †Gemmarcula arizonensis – type locality for species
 * †Gemmarcula menardi
 * Bakevelliidae - Gervillia inflata.JPG †[[Gervillia]]
 * †Gervillia cholla
 * †Gervillia heinemani
 * †Gervillia navajovus – type locality for species
 * †Gervillia rasori
 * Ginkgo
 * †Grallator
 * †Grallator cursorius
 * †Granocardium
 * †Granocardium trite
 * †Graphidula
 * †Graphidula walcotti
 * †Gregania – tentative report
 * GryphaeidaeCretaceousTexas.jpg †[[Gryphaea]]
 * †Gryphaeostrea
 * †Gryphaeostrea elderi – type locality for species
 * †Gryphaeostrea nationsi – type locality for species
 * Gyrodes
 * †Gyrodes conradi
 * †Gyrodes depressa
 * †Gyrodes tramitensis – or unidentified comparable form
 * †Gyrolepis
 * †Gyrotropis
 * †Gyrotropis nationsi – type locality for species

H

 * Hadrokkosaurus NMMNHS.jpg †[[Hadrokkosaurus]] – type locality for genus
 * †Hadrokkosaurus bradyi – type locality for species
 * †Hamites
 * †Hamites simplex
 * †Hamulus
 * Hemiaster
 * †Hemiaster jacksoni – or unidentified comparable form
 * †Hesperosuchus – type locality for genus
 * †Hesperosuchus agilis – type locality for species
 * Homarus
 * †Hopiichnus – type locality for genus
 * †Hopiichnus shingi – type locality for species
 * †Hybodus

I

 * †Immunitoceras
 * †Immunitoceras immunitum
 * Inoceramus steenstrup, world's largest fossil mollusk.jpg †[[Inoceramus]]
 * †Inoceramus corpulentas
 * †Inoceramus dimidius – or unidentified comparable form
 * †Inoceramus flavus
 * †Inoceramus heinzi – or unidentified related form
 * †Inoceramus lamarcki
 * †Inoceramus nodai
 * †Inoceramus pictus
 * †Inoceramus tenuistriatus – tentative report
 * †Isochirotherium
 * †Isochirotherium coltoni – type locality for species
 * †Isochirotherium marshalli

K

 * †Kamerunoceras
 * †Kamerunoceras turoniense
 * Kayentachelys NT cropped.png †[[Kayentachelys]] – type locality for genus
 * †Kayentachelys aprix – type locality for species
 * †Kayentapus – type locality for genus
 * †Kayentapus hopii – type locality for species
 * †Kayentasuchus – type locality for genus
 * †Kayentasuchus walkeri – type locality for species
 * †Kayentatherium – type locality for genus
 * †Kayentatherium wellesi – type locality for species
 * Kayentavenator.jpg †[[Kayentavenator]] – type locality for genus
 * †Kayentavenator elysiae – type locality for species
 * †Kazanskyella
 * †Kazanskyella arizonica
 * †Koskinonodon
 * †Koskinonodon perfectus
 * †Koupichnium – probable lapsus calami of Kouphichnium
 * †Kraterokheirodon – type locality for genus
 * †Kraterokheirodon colberti – type locality for species
 * †Kummelonautilus

L

 * †Lasalichthys – or unidentified comparable form
 * Laternula
 * †Laternula lineata
 * †Legumen
 * †Legumen ligula – or unidentified comparable form
 * Lepisosteus
 * Leptosuchus crosbiensis cropped.jpg †[[Leptosuchus]]
 * †Leptosuchus crosbiensis
 * †Levicerithium
 * †Levicerithium basicostae
 * †Levicerithium micronema – tentative report
 * †Levicerithium timberanum – or unidentified comparable form
 * Lima
 * †Lima cholla
 * †Lima espinal
 * †Lima muralensis
 * †Lima utahensis
 * Limatula
 * †Limatula kochi
 * †Linearis
 * †Linearis striatimarginata
 * †Linearis whitei
 * †Lingula
 * †Lingula subspatula
 * †Liopistha
 * †Liopistha meeki
 * Lissodus fossil cropped.png †[[Lissodus]] – tentative report
 * †Lithocodium
 * Lithophaga
 * †Lonchidion
 * †Lonchidion humblei
 * †Longitubus
 * Lopha
 * †Lopha bellaplicata
 * †Lopha staufferi
 * †Lucina
 * †Lucina subundata
 * Euspira lewisii 3 cropped.jpg [[Lunatia]] – tentative report
 * †Lutema
 * †Lutema hitzi

M

 * Phytosaurs cropped.jpg †[[Machaeroprosopus]] – type locality for genus
 * †Machaeroprosopus buceros
 * †Machaeroprosopus jablonskiae – type locality for species
 * †Machaeroprosopus mccauleyi – type locality for species
 * †Machaeroprosopus pristinus – type locality for species
 * †Machaeroprosopus tenuis – type locality for species
 * †Machaeroprosopus validus – type locality for species
 * †Mammillopora
 * †Mammillopora encrusta – type locality for species
 * †Mammites
 * †Mammites nodosoides
 * †Masculostrobus
 * †Masculostrobus clathratus – type locality for species
 * †Mathilia – tentative report
 * †Mathilia ripleyana
 * †Meekia
 * †Megalosauripus
 * †Melvius
 * Membranipora – or unidentified comparable form
 * †Mesolanites
 * †Mesostoma
 * †Metaptychoceras
 * †Metaptychoceras reesidei
 * †Metoicoceras
 * †Metoicoceras geslinianum
 * †Metoicoceras mosbyense
 * Metoposaurus size comparison with human.png †[[Metoposaurus]]
 * †Metoposaurus fraasi – type locality for species
 * †Microsolena
 * †Microsolena texana
 * †Modiolus
 * †Modiolus attenuatus – or unidentified comparable form
 * †Modiolus coloradoensis
 * †Modiolus perryi – type locality for species
 * †Moenkopia – type locality for genus
 * †Moenkopia wellesi – type locality for species
 * †Monopleura
 * †Monopleura marcida – or unidentified comparable form
 * †Moremanoceras
 * †Moremanoceras scotti
 * Morganucodon.jpg †[[Morganucodon]]
 * †Morrowites
 * †Mytiloides
 * †Mytiloides columbianus
 * †Mytiloides duplicostasus – or unidentified related form
 * †Mytiloides hercynicus
 * †Mytiloides kossmati
 * †Mytiloides labiatus
 * †Mytiloides latus – or unidentified comparable form
 * †Mytiloides mytiloides
 * †Mytiloides opalensis
 * †Mytiloides submytiloides
 * †Mytilus – tentative report

N

 * †Nannometoicoceras
 * †Nannometoicoceras acceleratum
 * †Navahopus – type locality for genus
 * †Navahopus falcipollex – type locality for species
 * †Neithea
 * †Neithea vicinalis
 * †Nemodon
 * †Neocardioceras
 * †Neocardioceras juddii
 * †Neocardioceras minutum
 * †Neoptychites
 * †Neoptychites cephalotus
 * Nerineidae - Nerinea sp..JPG †[[Nerinea]]
 * Nerita
 * †Nerita spp.
 * Neritina
 * †Neritina spp.
 * †Nigericeras
 * †Nigericeras ogojaense – or unidentified comparable form
 * Nucula
 * †Nucula coloradoensis
 * Nuculana
 * †Nuculana mutuata

O

 * †Obnixia – type locality for genus
 * †Obnixia thaynesiana
 * Oligokyphus BW.jpg †[[Oligokyphus]]
 * †Opis
 * †Opis elevata
 * †Orbitolina
 * †Orbitolina texana
 * Ostrea
 * †Ostrea anomioides
 * †Ostrea edwilsoni
 * †Oxytoma
 * †Oxytoma arizonensis – type locality for species

P

 * †Pachyrhizodus – or unidentified comparable form
 * †Paleopsephea
 * †Paleopsephea arizonensis – type locality for species
 * †Paracanthohoplites
 * †Paracanthohoplites meridionalis
 * †Parasimilia
 * †Parasimilia spp.
 * Paleorhinus.jpg †[[Parasuchus]]
 * †Paratypothorax
 * †Parmicorbula
 * †Parrishea
 * †Parrishia – type locality for genus
 * †Parrishia mccreai – type locality for species
 * Parvilucina
 * †Parvilucina juvenis
 * †Pecten
 * †Pecten peregrina
 * †Perissoptera
 * †Perissoptera prolabiata
 * †Permocalculus
 * Petrophyllia
 * †Petrophyllia dartoni
 * †Pharodina
 * †Pharodina ferrana
 * †Phelopteria
 * †Phelopteria A – informal
 * †Phelopteria B – informal
 * †Phelopteria C – informal
 * †Phelopteria dalli
 * †Phelopteria E – informal
 * †Phelopteria F – informal
 * †Phelopteria gastrodes
 * †Phelopteria minuta
 * †Phoebodus
 * Pholadomya
 * †Pholadomya coloradoensis
 * Physa
 * †Physa reesidei – or unidentified comparable form
 * †Pinna
 * †Pinna kauffmani – type locality for species
 * †Pinna petrina
 * †Pirsilia
 * †Placenticeras
 * †Placenticeras cumminsi
 * Placerias hesternus.jpg †[[Placerias]] – type locality for genus
 * †Placerias hesternus – type locality for species
 * †Plastomenus
 * †Pleisiopinna – tentative report
 * †Pleisopinna – tentative report
 * †Pleuriocardia
 * †Pleuriocardia pauperculum
 * Plicatula
 * †Plicatula ferryi
 * †Plicatula hydrotheca
 * †Pollex – tentative report
 * Polydora – tentative report
 * †Polystrata
 * †Polystrata alba
 * †Polytremacis
 * Poposaurus gracilis (1).jpg †[[Poposaurus]]
 * †Poposaurus gracilis
 * Poromya
 * †Poromya lohaliensis – type locality for species
 * †Postosuchus
 * †Postosuchus kirkpatricki
 * †Pravusuchus
 * †Pravusuchus hortus
 * †Prionocyclus
 * †Prionocyclus hyatti
 * †Prionocyclus percarinatus
 * †Procolophonichnium
 * Prosalirus BW.jpg †[[Prosalirus]] – type locality for genus
 * †Prosalirus bitis – type locality for species
 * †Protelliptio – tentative report
 * †Protome – type locality for genus
 * †Protome batalaria – type locality for species
 * †Protosuchus – type locality for genus
 * †Protosuchus richardsoni – type locality for species
 * †Pseudaspidoceras
 * †Pseudaspidoceras flexuosum
 * †Pseudaspidoceras pseudonodosoides
 * †Pseudocalycoceras
 * †Pseudocalycoceras angolaense
 * †Pseudoperna
 * †Pseudoperna bentonense
 * †Pseudoperna bentonensis
 * †Pseudopetalodontia
 * †Pseudopetalodontia felixi
 * †Pseudoptera
 * †Pseudoptera propleura
 * †Psilomya
 * †Psilomya concentrica
 * †Psilomya elongata
 * †Psilomya meeki
 * †Psilothyris
 * †Psilothyris occidentalis
 * †Pteraichnus – type locality for genus
 * †Pteraichnus saltwashensis – type locality for species
 * †Puebloites
 * †Puebloites greenhornensis
 * †Puebloites spiralis
 * Pycnodonte
 * †Pycnodonte kansasense – tentative report
 * †Pycnodonte kellumi – or unidentified related form
 * †Pycnodonte newberryi
 * †Pyktes
 * †Pyktes fusiformis
 * †Pyncnodonte
 * †Pyncnodonte kellumi – or unidentified related form
 * †Pyncnodonte newberryi
 * †Pyrgulifera
 * †Pyrgulifera ornata
 * †Pyropsis
 * †Pyropsis coloradoensis – or unidentified comparable form
 * †Pyropsis kochi – type locality for species

Q

 * †Quasicyclotosaurus – type locality for genus
 * †Quasicyclotosaurus campi – type locality for species
 * †Quitmaniceras
 * †Quitmaniceras reaseri – or unidentified comparable form

R

 * †Radiolites
 * Ramphonotus – or unidentified comparable form
 * †Rectithyris
 * †Rectithyris vespertina – type locality for species
 * †Reticulodus – type locality for genus
 * †Reticulodus synergus – type locality for species
 * Revueltosaurus.jpg †[[Revueltosaurus]]
 * †Revueltosaurus callenderi
 * †Revueltosaurus hunti
 * †Rhadalognathus – type locality for genus
 * †Rhadalognathus boweni – type locality for species
 * †Rhamphinion – type locality for genus
 * †Rhamphinion jenkinsi – type locality for species
 * †Rhombopsis – tentative report
 * †Rhombopsis huerfanensis
 * †Rhynchosauroides
 * †Rhynchosauroides schochardti
 * †Rhynchostreon
 * †Rhynchostreon levis
 * Ringicula doliaris.png [[Ringicula]]
 * †Ringicula codellana
 * †Rioarribasuchus
 * †Rioarribasuchus chamaensis
 * Rostellaria
 * †Rostellaria venenatus – tentative report
 * †Rotodactylus – type locality for genus
 * †Rotodactylus bradyi – type locality for species
 * †Rotodactylus cursorius – type locality for species
 * †Rubroceras
 * †Rubroceras rotundum
 * Rutiodon carolinensis cropped.jpg †[[Rutiodon]]

S

 * Sarahsaurus cropped.png †[[Sarahsaurus]] – type locality for genus
 * †Sarahsaurus aurifontanalis – type locality for species
 * Scalpellum – tentative report
 * †Scaphites
 * †Scaphites larvaeformis
 * †Sciponoceras
 * †Sciponoceras gracile
 * †Scutarx – type locality for genus
 * †Scutarx deltatylus – type locality for species
 * †Scutellosaurus – type locality for genus
 * †Scutellosaurus lawleri – type locality for species
 * †Segisaurus – type locality for genus
 * †Segisaurus halli – type locality for species
 * †Selaginella
 * †Selaginella anasazia – type locality for species
 * Semionotus bergeri.jpg †[[Semionotus]] – or unidentified comparable form
 * †Senis
 * †Senis elongatus
 * †Sergipia
 * †Sergipia hartti – tentative report
 * Serpula
 * †Serpula implicata
 * †Serpula intrica
 * †Serpula large
 * †Shuvosaurus
 * †Shuvosaurus inexpectatus
 * †Sinzowiella
 * †Sinzowiella spathi
 * †Smilosuchus – type locality for genus
 * †Smilosuchus adamanensis – type locality for species
 * †Smilosuchus gregorii – type locality for species
 * †Smilosuchus lithodendrorum – type locality for species
 * Solemya
 * †Solemya obscura
 * Sonorasaurus thompsoni.jpg †[[Sonorasaurus]] – type locality for genus
 * †Sonorasaurus thompsoni – type locality for species
 * †Spathites
 * †Spathites puercoensis
 * Spirorbis
 * Squilla – tentative report
 * †Stagonolepis
 * †Stanocephalosaurus – type locality for genus
 * †Stanocephalosaurus birdi – type locality for species
 * †Stanocephalosaurus new species – informal
 * †Stoliczkaia
 * †Stoliczkaia scotti
 * †Stomohamites
 * †Stylocyathus
 * †Sumitomoceras
 * †Sumitomoceras conlini
 * †Synaptichnium
 * †Synaptichnium cameronensis – type locality for species
 * †Synaptichnium diabloensis – type locality for species
 * †Syncyclonema
 * †Syncyclonema spp.
 * †Syntarsus

T

 * †Tanytrachelos
 * †Tecovasaurus
 * †Tecovasaurus murryi
 * †Tecovasuchus
 * †Tecovasuchus chatterjeei
 * †Tectaplica – tentative report
 * †Tectaplica utahensis
 * Tellina
 * †Tellina carlilana – type locality for species
 * †Tenea
 * Tenontosaurus BW.jpg †[[Tenontosaurus]]
 * †Terebrimya
 * Teredolithus
 * †Therapsipus – type locality for genus
 * †Therapsipus cumminsi – type locality for species
 * †Thomasites
 * †Thomasites gongilensis – or unidentified comparable form
 * †Toucasia
 * †Toucasia hancockensis
 * †Tragodesmoceras
 * †Tragodesmoceras bassi
 * †Tragodesmoceras socorroense
 * †Triasamnicola – or unidentified comparable form
 * †Triasamnicola pilsbryi
 * †Trigonia
 * †Trigonia aliformis - or unidentified loosely related form
 * †Trigonia cragini
 * †Trigonia guildi
 * †Trigonia kitchini
 * †Trigonia mearnsi
 * †Trigonia reesidei
 * †Trigonia resoluta
 * †Trigonia saavedra
 * †Trigonia stolleyi
 * †Trigonia weaveri
 * Trilophosaurus buettneri (1).jpg †[[Trilophosaurus]]
 * †Trilophosaurus buettneri
 * †Trilophosaurus jacobsi – type locality for species
 * †Triodus
 * †Triodus moorei
 * Trochocyathus
 * Turritella
 * †Turritella A – informal
 * †Turritella B – informal
 * †Turritella cobbani – type locality for species
 * †Turritella codellana – type locality for species
 * †Turritella kauffmani – type locality for species
 * †Turritella whitei
 * †Turseodus
 * †Turseodus dolorensis – or unidentified comparable form
 * Typothorax coccinarum cropped.jpg †[[Typothorax]]
 * †Typothorax coccinarum

U

 * †Uatchitodon
 * †Uatchitodon schneideri
 * †Unicardium
 * Unio

V

 * Vancleavea.jpg †[[Vancleavea]] – type locality for genus
 * †Vancleavea campi – type locality for species
 * †Vascoceras
 * †Vascoceras diartianum
 * †Veniella
 * †Veniella goniophora
 * †Veniella mortoni
 * †Vigilius
 * †Vigilius wellesi
 * Viviparus
 * †Voysa
 * †Voysa varia
 * Vulsella

W

 * †Watinoceras
 * †Watinoceras coloradoense
 * †Watinoceras devonense
 * †Watinoceras hattini
 * †Watinoceras praecursor – or unidentified comparable form
 * †Watinoceras spp.
 * †Weeksia
 * †Wellesaurus
 * †Wellesaurus peabodyi – type locality for species
 * †Worthoceras
 * †Worthoceras gibbosum
 * †Worthoceras vermiculum

Y

 * †Yezoites
 * †Yezoites delicatulus