Crayfish
Fossil record

Fossil burrows very similar in construction to those of modern crayfish and likely produced by early crayfish are known from the Early Permian (~300-270 million years ago) of equatorial Pangea, in what is now North America (Washington Formation), and Europe (Sardinia). The oldest body fossils assigned to crayfish are known from the Late Triassic (~230-200 million years ago) Chinle Formation of North America, assigned to the species " Enoploclytia " porteri and Camborygma eumekenomos, which are not assigned to any modern families. An indeterminate member of the modern family Cambaridae is known from the Late Jurassic Morrison Formation of North America. The earliest records of other modern families date to the Early Cretaceous, including the parastacid Palaeoechinastacus from Australia which is 115 million years old, the cambaroidid Palaeocambarus from the Yixian Formation of China which is likely around 120 million years old (Barremian - Aptian), and the astacid " Austropotamobius " llopisi from the Las Hoyas site in Spain (Barremian).
keywords:existence