Over the last two months, two new books on parasitism in the fossil record were published as part of the Topics in Geobiology series. The last one appeared online on 1 January 2022.The very first chapter is about how much we know about parasitism in the fossil record in general and, in particular, how preservation has affected what we know about parasitism.
This research emphasizes that some modes of parasitism have a much higher preservation potential than others. The generally soft-bodied and small parasites can leave a trace on the hardened host shell or skeleton, which very much enhances their chance of being discovered. Examples are trematode pits in bivalve shells and isopod-induced swellings in the gill region of decapod crustaceans. These study systems hold to potential for much more research. Other rich sources of parasites are parasite body fossils preserved in amber and coprolites (fossil dung). However, particularly amber is only known from some places and periods. When body fossils of parasites are well-preserved, much may be learned about the taxonomy and ecology of these parasites. The main conclusion is that much more targeted research is warranted on parasites.