Dinosaur taphonomy of the Jurassic Shishugou Formation (Northern Junggar Basin, NW China) – insights from bioerosional trace fossils on bone

Abstract

Bioerosional trace fossils can offer invaluable insights into taphonomic processes, ecosystem dynamics and environmental conditions that are not obtainable by other lines of evidence. Here, we describe the first invertebrate trace fossils on dinosaur bone from the Upper Jurassic Shishugou Formation of the northeastern Junggar Basin. The traces occur as spherical holes in the bone, closely resembling boreholes attributed to either indeterminate insects or dermestid beetles and thus they are here likewise ascribed to feeding and/or pupation by necrophagous insects. Such bioerosional trace fossils have several taphonomical and palaeoecological implications for they are only inflicted on subaerially exposed tissues and preferentially when carcasses are desiccated. We, therefore, conclude that the dinosaur carcass was exposed for at least several weeks under a semi-arid and seasonal climate before it was buried by sediment. This supports the general palaeoclimatological and paleoenvironmental reconstructions for the Shishugou Formation from sedimentological data. Moreover, this is the first evidence for invertebrate–vertebrate interactions from the Late Jurassic of Asia, offering a novel glimpse into the diverse biotic relationships of this ancient Jurassic ecosystem.