Publisher Summary The trace fossil Zoophycos can be considered a good example of a taxonomic problem, resulting from old interpretations and lack of studies on the type material. Zoophycos is a complex and enigmatic ichnofossil that has challenged generations of geologists and ichnologists for over a century. Till now, its producer or producers remain elusive. This ichnofossil is cosmopolitan and it occurs in diverse marine sedimentary facies ranging from Palaeozoic to Holocene. The trace fossils commonly included in the ichnogenus Zoophycos are characterized by a great morphological complexity and variability, which has resulted in confusing ichnotaxonomy and diverse interpretations of the producer and behavior. The palaeoenvironmental significance and the ethology of the supposed tracemakers have been the object of many studies, but till date, there has been no real agreement among ichnologists. The necessity to change the ichnogeneric name or to find a new lectotype arises from this finding. By chance, Massalongo collected other specimens, and his definition of the ichnogenus Zoophycos covers all of these fossils. Even though the most complete specimen of the type ichnospecies has not been found yet, the presence of its counterpart is sufficient to make it the new type specimen. The name Zoophycos can be conserved. This chapter provides new taxonomic data about the ichnogenus Zoophycos. It will not solve all the other controversies concerning this enigmatic and complex trace fossil, but will contribute to the clearing up of some nomenclatural problems concerning the type material.