How long ago did the association between termites and gut symbionts form? A fossil dated between 97 and 110 million years ago provides clear evidence of flagellates associated with the termite gut from the early Cretaceous. The termite, Kalotermes burmensis, had suffered damage to its abdomen, opening its gut when it became embedded in amber. The damage exposed the gut and preserved the flagellates in a manner that they are visible 100 million years later. The fossil was investigated by George Poinar* who was able to observe and identify 10 new fossil species of flagellates within the termite gut.
*George O Poinar. Description of an early Cretaceous termite and its associated intestinal protozoa, with comments on their co-evolution. Parasites & Vectors 2009, 2:12