Aachenosaurus – petrified woodAardonyx“Abdallahsaurus” – nomen nudum, probably GiraffatitanAbelisaurusAbrictosaurusAbrosaurusAbydosaurusAcanthopholisAchelousaurusAcheroraptorAchillesaurusAchillobator“Acracanthus” – original invalid name of AcrocanthosaurusAcristavusAcrocanthosaurusAcrotholusActiosaurus – probably an ichthyosaurAdamantisaurusAdasaurusAdeopapposaurusAegyptosaurusAeolosaurusAepisaurusAerosteonAetonyx – possible junior synonym of MassospondylusAfrovenatorAgathaumasAggiosaurus – actually a metriorhynchid crocodilianAgilisaurusAgnosphitysAgrosaurus – probably a junior synonym of ThecodontosaurusAgujaceratopsAgustiniaAhshislepelta“Airakoraptor” – nomen nudumAjancingeniaAjkaceratopsAlamosaurus“Alashansaurus” – nomen nudum; ShaochilongAlaskacephaleAlbalophosaurusAlbertaceratopsAlbertadromeusAlbertonykusAlbertosaurusAlbinykusAlbisaurus – a non-dinosaurian reptileAlectrosaurusAletopeltaAlgoasaurusAlioramusAliwalia – junior synonym of Eucnemesaurus
Aachenosaurus – petrified woodAardonyx“Abdallahsaurus” – nomen nudum, probably GiraffatitanAbelisaurusAbrictosaurusAbrosaurusAbydosaurusAcanthopholisAchelousaurusAcheroraptorAchillesaurusAchillobator“Acracanthus” – original invalid name of AcrocanthosaurusAcristavusAcrocanthosaurusAcrotholusActiosaurus – probably an ichthyosaurAdamantisaurusAdasaurusAdeopapposaurusAegyptosaurusAeolosaurusAepisaurusAerosteonAetonyx – possible junior synonym of MassospondylusAfrovenatorAgathaumasAggiosaurus – actually a metriorhynchid crocodilianAgilisaurusAgnosphitysAgrosaurus – probably a junior synonym of ThecodontosaurusAgujaceratopsAgustiniaAhshislepelta“Airakoraptor” – nomen nudumAjancingeniaAjkaceratopsAlamosaurus“Alashansaurus” – nomen nudum; ShaochilongAlaskacephaleAlbalophosaurusAlbertaceratopsAlbertadromeusAlbertonykusAlbertosaurusAlbinykusAlbisaurus – a non-dinosaurian reptileAlectrosaurusAletopeltaAlgoasaurusAlioramusAliwalia – junior synonym of Eucnemesaurus