Treptichnus_pedum
Treptichnus
Preserved burrow of an animal
Treptichnus (formerly named Phycodes, Manykodes by J. Dzik,[2] and also known as Trichophycus[3]) is the preserved burrow of an animal. As such, it is regarded as the earliest widespread complex trace fossil. Its earliest appearance, around 542 mya,[4] which was contemporaneous with the last of the Ediacaran biota, is used to help define the dividing line, considered geologically at 541 mya, between the Ediacaran and Cambrian periods.[5][6] It is last seen in the fossil record during the Cenomanian (99.7 Ma).[1]