The Aaleanian Age (174–170 Ma) is the first age in the Middle Jurassic Epoch of the Jurassic Period of the Mesozoic Era. It occurs after the Toarcian Age, and before the Bajocian Age.
174.1±1.0–170.3±1.4 Ma
Many gymnosperm groups present
Conifers (including Cheirolepidaceae)