Friday, May 15, 2009

Mutualism in Situ – Fossilized Symbionts

A chunk of fossilized amber recovered from a mine in the Hukawng Valley of Myanmar has been found to encase a Cretaceous termite with several species of formerly egressing protozoa attached to an abdominal wound sustained more than 100 million years ago. This snapshot of symbiosis demonstrates that the relationship between the cellulolytic protist and its eusocial dwelling have been a long time in the making.

Cool fossil… Here’s the background section of the article:

Termites are one of the most successful eusocial insect groups today and certainly the most notorious as a result of their damage to human dwellings. Their success can be attributed in large part to microbial (especially protozoa and bacterial) symbionts harbored in their alimentary tract. Especially important are gut protists, which are essential for the survival of termites feeding on lignocelluloses. While termites do produce endogenous cellulases from salivary glands and gut cells, cellulolytic protists are crucial for the complete digestion of cellulose in wood-feeding termites. In the lower termites, these symbionts are mostly flagellates belonging to the Oxymonadida, Trichomonada and Hypermastigida. Flagellates associated with an Early Cretaceous lower termite of the family Kalotermitidae are described and compared with mutualistic flagellates of extant kalotermitids. This discovery shows that, while the protist species represent different genera and species, mutualistic associations between protists and termites had already been established some 100 million years ago. The present study represents the earliest fossil record of mutualism between microorganisms and animals.

The full text and several images can be found free HERE.

George O Poinar Jr. Description of an early Cretaceous termite (Isoptera: Kalotermitidae) and its associated intestinal protozoa, with comments on their co-evolution. Parasites & Vectors, 2009; 2 (12) DOI: 10.1186/1756-3305-2-12

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