Cockroach Ancestor Predates Dinosaurs

If it seems like cockroaches have been around forever, they nearly have. Check out this 300-million-year-old cockroach ancestor that lived several million years before the world's first dinosaurs emerged.

(Credit: Imperial College London and the Natural History Museum)

A new 3-D virtual model of the insect is described in the journal Biology Letters.

Imperial College London scientists created the model, which you'll view shortly, to show all of the details on Archimylacris eggintoni, which is an ancient ancestor of modern cockroaches, mantises and termites. This insect scuttled around early forests during the Carboniferous period 359 – 299 million years ago, which was a time when life had recently emerged from the oceans to live on land.

This cockroach ancestor was about 3.5 inches long and 1.6 inches wide, so it was a pretty sizable bug even then.

Project leader Russell Garwood, a PhD student from the Department of Earth Science and Engineering at Imperial College London, said, "The Carboniferous period is sometimes referred to as the age of the cockroach because fossils of Archimylacris eggintoni and its relatives are amongst the most common insects from this time period.

They are found all over the world. People joke about it being impossible to kill cockroaches and our 3D model almost brings this one back to life. Thanks to our 3D modeling process, we can see how Archimylacris eggintoni's limbs were well adapted for all terrains, as it was not only adept in the air but also very agile on the ground."

The model additionally reveals that the cockroach ancestor had sticky structures on its legs called euplantulae. The researchers believe the euplantulae enabled Archimylacris eggintoni to stick to smooth surfaces such as leaves as they climbed across them, which may have helped them to lay their eggs above the ground in safer locations away from predators.

It also had claws at the base of its legs, which helped it to climb rough surfaces, like trees, so that it could perch above the forest floor for safety or find alternate sources of food higher up.

Check out the mouth area in the model too. These insects, like today's cockroaches, can grind up their food. While today such food might be some goody found in your pantry, these prehistoric insects mostly munched on decaying leaf and insect matter.

Garwood said, "We now think this ancient ancestor of the cockroach spent most of the day on the forest floor, living in and eating lots of rotting plant and insect matter, which was probably the bug equivalent of heaven. We think it could have used its speed to evade predators and its climbing abilities to scale trees and lay eggs on leaves, much in the same way that modern forest cockroaches do today."

In future, 3-D models are planned for early spider-like organisms and other species from the Carboniferous period.