<br> Australian forests and woodlands are dominated by the species-rich (&gt; 700 spp.) genus<br> Eucalyptus<br> L’Hér. (Myrtaceae). Despite this modern-day dominance, the earliest macrofossil evidence of the genus comes not from Australia, but from the early Eocene Laguna del Hunco locality in Argentinean Patagonia, consisting of abundant vegetative and reproductive material. The leaves, assigned to the fossil species<br> Eucalyptus frenguelliana<br> Gandolfo & Zamaloa, record a diverse suite of insect and pathogenic damage that closely matches that observed on 36 extant, rainforest-associated<br> Eucalyptus<br> species. Here, I provide detailed morphological descriptions and photographic documentation of this damage, recorded on 284<br> E. frenguelliana<br> leaves, together with extensive comparisons to analogous damage observed in extant<br> Eucalyptus<br> herbarium specimens (&gt; 10,000 sheets reviewed). From the fossil material, I describe a diverse suite of 33 insect-mediated and pathogenic damage types (DTs), including twelve types of external feeding interactions, one of piercing-and-sucking marks, five of galls, ten of mines, three of pathogenic traces, and two of oviposition scars. This elevated number of DTs, encompassing a wide range of ecological interactions, indicates that<br> E. frenguelliana<br> was an important ecological resource in ancient Patagonian rainforests. Some of the fossil mines were probably created by micromoths in the families Nepticulidae and Gracillariidae, as well as flies in the family Agromyzidae. However, most of the insect and pathogenic damage observed in the fossils and their corresponding extant analogs was produced by still-unknown culprits, underscoring gaps in our knowledge of<br> Eucalyptus<br> -associated communities and their assembly through evolutionary time.<br>
