Palaeoecology of the trace fossil Gordia and its interaction with nonmineralizing taxa from the early Middle Cambrian Kaili Biota, Guizhou province, South China

Gordia marina is the most common ichnospecies in the Kaili Biota, Guizhou, China. Among 1070 non-biomineralizing body fossils examined, more than 220 specimens in museum collections were observed to be associated with extensive Gordia traces. Approximately 55% of the discoidal animal Pararotadiscus quizhouensis are associated with Gordia. The complex courses of the burrows in the area of the body fossils and their recurvature at the periphery confirm that this association is not fortuitous. The length and complexity of the burrow are inversely proportional to the quality of soft-part preservation in the animals. Gordia makers, possibly priapulids, accessed buried carcasses by burrowing, then exploited them by deposit feeding the nutrient-rich sediments immediately above or below the planes of Pararotadiscus discs and bivalved arthropod carapaces, including Tuzoia, Canadaspis, and Waptia.