Arthropod gap

The arthropod gap is an apparent gap in the arthropod fossil record used in the study of evolutionary biology. It still occurs in the early Carboniferous, coinciding and extending past the Romer's gap for tetrapods, which may have been caused by low oxygen levels in the atmosphere.
The discovery of the Devonian insect species "Strudiella devonica" in 2012, and dated to 370 million years ago, reduces a previous gap of 45 million years in the evolutionary history of insects, from 385 million to 325 million years ago.
It is also sometimes known as the hexapoda gap.