Oldest Omaliini Beetle Found in Unusual Cloudy Amber
Researchers have recently discovered one of the oldest members of a tribe of beetles, setting the date of their first appearance back to at least 100 million years ago. Interestingly, this beetle was discovered in opaque amber, a type of prehistoric sap that is not transparent.
Unlike most fossil finds, amber is exceptionally good at preserving ancient specimens, down to even the tiniest of bristles. Even in prehistoric times, trees secreted sticky resin to patch their wounds - much like a blister. This resin hardens over extended periods of time, eventually becoming hard and transparent, providing a remarkably clear window into the past if it happened to encase an insect or other tiny organism.
According to the Virtual Fossil Museum, resin consist of mainly carbon and hydrogen, allowing it to readily form stiffening molecular bonds. In the absence of oxygen, microbial life traditionally involved in decomposition cannot gain access to organisms encased in amber, allowing perfect preservation. Nature World News recently reported how radioactive fallout can function in a similar manner, where some trees in Chernobyl's infamous Red Forest have yet to decompose even decades after they died.
Unfortunately, not all amber is the remarkably clear window into the past it promises to be. Some amber becomes clouded by particulates such as dust, ash, or simply its own chemical composition. In these cases, researchers find themselves forced to guess if an amber sample would have any promising specimens within.
As described in a study recently published in the journal Annals of the Entomological Society of America, that's exactly what an international team of researchers did with a particularly large chunk of opaque amber.
Using a complicated "phase-contrast X-ray synchrotron imaging technique," researchers were able to see detailed imagery of a wide variety of insects trapped in the dark amber.
Most importantly, the identified a rove beetle that was clearly a member of the tribe Omaliini, a type of insect that has never been found in amber before, and was thought to be too 'young' to be found in such fossils.
Insects can be a tremendous resource for understanding the ancient world and ancient ecosystems, and this discovery certainly resets what entomologists thought they knew about this specific beetle's history.