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
†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
†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 – 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 †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