And the insect is also the oldest cave-dwelling animal ever found.
By Bruno Carbinatto
21 Feb 2020, 5:43 pm
Although they do not survive nuclear disasters, legend says the legend, cockroaches are really resistant. A team of scientists found a practically intact cockroach preserved in amber, dating from 99 million years ago. The insect became the oldest animal ever found in a cave – all other specimens are from the Cenozoic era, from 65 million years ago, when the dinosaurs had already been extinct.
The fossil was found in the Hukawng valley in Myanmar, and dating techniques on the rocks around it provided its age. She lived in the Cretaceous, when the last dinosaurs were still around. The study describing the discovery can be accessed on here.
Several characteristics of the cockroach (which is surprisingly conserved, as you can see in the image) indicate that it was an animal that inhabited caves. The first is its pale color, indicating the loss of pigments; the second is that their wings and eyes are smaller than normal cockroaches, while the ones before are larger – presumably to aid locomotion in the dark. This makes it the oldest cave dwelling animal ever found.
The cockroach family, in the philological sense of the term, is called Nocticolidae and comprises several species that still exist and are known to inhabit caves. The current representatives of this family of cockroaches differ greatly from the fossil – possibly because, after the supercontinent Gondwana separated, more or less 180 million years ago, different species became isolated and developed their own characteristics.
It is not known exactly why there are no cave animals as old as the cockroach – the majority that exist until today appeared in the Cenozoic. One possibility is that some mysterious factor has caused the extinction of most Mesozoic cave species.
Another mystery is how a cave cockroach ended up fossilized in amber – which comes from the sap of trees. But this is perhaps easier to explain: the cockroach was probably one of the most astute of its kind and ventured out of the cave, where there were probably trees.
It is not exactly a surprise an insect as old as this. Arthropods appeared about 500 million years ago, according to predictions, first in the form of crustaceans and arachnids and then insects themselves. For comparison, the Homo erectus, our ancestor, only appeared about 2 million years ago. And they are still here tormenting us, just like the dinosaurs tormented us.