Interpreting fossilized nervous tissues

Paleoneuranatomy is an emerging subfield of paleontological research with great potential for the study of evolution. However, the interpretation of fossilized nervous tissues is a difficult task and presently lacks a rigorous methodology. We critically review here cases of neural tissue preservation reported in Cambrian arthropods, following a set of fundamental paleontological criteria for their recognition. These criteria are based on a variety of taphonomic parameters and account for morphoanatomical complexity. Application of these criteria shows that firm evidence for fossilized nervous tissues is less abundant and detailed than previously reported, and we synthesize here evidence that has stronger support. We argue that the vascular system, and in particular its lacunae, may be central to the understanding of many of the fossilized peri‐intestinal features known across Cambrian arthropods. In conclusion, our results suggest the need for caution in the interpretation of evidence for fossilized neural tissue, which will increase the accuracy of evolutionary scenarios. Also see the video here: https://youtu.be/2_JlQepRTb0 Burgess‐Shale type fossils have yielded remains of nervous tissues and paved the way for the study of paleoneuroanatomy, but their interpretation has suffered from inconsistent methodology. Based on a critical review of case studies on extinct arthropods, we demonstrate how a thorough understanding of taphonomy and morphoanatomical complexity are essential to an accurate description of fossilized brains.