Largest cockroach fossil predates dinosaurs

An geology student in Ohio has found the largest-ever complete fossil of a cockroach, a nine-centimetre long insect that lived 300 million years ago, well before the first dinosaurs.

Cary Easterday, a master's student at Ohio State University, found the fossil roach, more than twice as big as a common American roach, in 1999.

The fossil is an unusual find because insects don't have bones or hard shells, parts that are usually preserved in fossil. Easterday credits unusual chemical properties of the site for preserving the insect.

The fossil reveals a lot of detail about the roach. The veins in the insect's wings, the bumps on its shell, its legs, its antennae and its mouth parts were all preserved in the fossil.

Easterday believes the roach was colourless, flat and female, and lived in leaf litter.

At the time the cockroach lived, Ohio was a tropical swamp that was rapidly drying out, so researchers hope this and other fossils found at the site will reveal how organisms coped with their changing environment.

Easterday presented his findings at the annual meeting of the Geological Society of America in Boston on Wednesday.

Other research presented at the meeting included:

  • evidence of an ancient ocean and active volcanoes on Mars
  • research on microbes than could lead to better clean-up of gasoline spills
  • a mapping of the location of the ancient harbour of Troy
  • a study on why large animals, such as mammoths and ground sloths, went extinct at the end of the Pleistocene era