A new ichnogenus Skolichnus for Chondrites hoernesii Ettingshausen, 1863, a deep-sea radial trace fossil from the Upper Cretaceous of the Polish Flysch Carpathians: Its taxonomy and palaeoecological interpretation as a deep-tier chemichnion

A new ichnogenus Skolichnus is proposed for Chondrites hoernesii Ettingshausen, 1863 on the basis of the re-discovered type material and additional material from the collections and from the field work. All the material derives from the deep-sea Campanian–lower Maastrichtian Kropivnik Fucoid Marl, in the same region of the Skole Nappe in the Polish Flysch Carpathians. Skolichnus hoernesii (Ettingshausen, 1863) comb. n. is a radial trace fossil, composed of thin, simple, horizontal or sub-horizontal, thinly lined, numerous rays produced deeply in the sediment from a fixed position in a supposed shaft. Its deep position below the Chondrites tier suggests that its producer (?a polychaete, ?a small crustacean) was a chemosymbiont. This trace fossil falls in the ethological category chemichnia. The position of tracemaker standing in the shaft with respect to the radial elements, i.e. head down when the radial elements are produced at the bottom of the shaft, or head up when the radial elements are produced at the top of the shaft, is proposed as a significant ichnotaxobase, which can be seen in its morphology or can be deduced from toponomic features.