Macaronichnus isp. associated with Piscichnus waitemata in the Miocene of Yonaguni-jima Island, southwest Japan

A composite ichnofossil is characterized by two or more discrete structures belonging to different ichnotaxa apparently making up a single structure. In this chapter, a peculiar specimen of a composite ichnofossil, which consists of separate elements assignable to Piscichnus waitemata and Macaronichnus isp., is described and interpreted. The fill in the host ichnofossil P. waitemata produced by feeding behavior of rays was completely emplaced by subsequently produced Macaronichnus isp. Producers of Macaronichnus isp. treated herein may have invaded the Piscichnus-fill in a very short period after the production of P. waitemata and completely reworked the sediment in the fill. The fill in Piscichnus was utilized by the Macaronichnus-producer as a new but temporary habitat. Such a deep penetration of Macaronichnus isp. has led to an unusually high potential of preservation for this ichnofossil, which typically represents the shallowest tier ichnofossil in the studied interval.