Arabian toad 
Arabian warbler 
Arabian wheatear 
Arachnocampa richardsae 
Arachnospila trivialis 
Arachnothelphusa merarapensis 
Aradus betulae 
Aradus funestus 
Araeopteron rufescens 
Arafura shrikethrush 
Aragua bistonaria 
Araguaian river dolphin 
Araneus ginninderranus 
Araneus nox 
Araneus pallidus 
Araneus pentagrammicus 
Araneus psittacinus 
Arboreal Bicolored Ant 
Arboreal salamander 
Arborvitae Leafminer 
Arc-eye hawkfish 
Arcfin Shrimpgoby 
Arch Duke Butterfly 
Archaeoattacus edwardsii