Aeronian

EtymologyName formalityFormalUsage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definitionFAD of the graptoliteDemirastrites triangulatusLower boundary GSSPHlásná Třebaň section, Czech Republic
49°55′23″N14°12′43″E / 49.9230°N 14.2119°E / 49.9230; 14.2119Lower GSSP ratified2024Upper boundary definitionFAD of the graptolite Spirograptus guerichiUpper boundary GSSPEl Pintado section, Seville, Spain
37°59′07″N5°55′43″W / 37.9853°N 5.9285°W / 37.9853; -5.9285Upper GSSP ratified2024

In the geologic timescale, the Aeronian is an age of the Llandovery Epoch of the SilurianPeriod of the PaleozoicEra of the PhanerozoicEon that began 440.5 ± 1.0 Ma and ended 438.6 ± 1.0 Ma (million years ago). The Aeronian Age succeeds the Rhuddanian Age and precedes the Telychian Age, all in the same epoch.

During the Aeronian the occurred in which graptolite diversity was greatly reduced. This event has been attested in locations such as today's Canada, Libya as well as in La Chilca Formation in Argentina (then part of Gondwana).

It was also from this time that the first gnathostomates appeared, represented by the genera Qianodus and Fanjingshania.