Morphology of Radhostium carpaticum Plička and Říha, 1989 in new finds from the Outer Western Carpathians (Upper Cretaceous – Eocene flysch deposits of the Biele Karpaty Mountains, Slovakia)

A new find of one specimen of the relatively rare trace fossil Radhostium carpaticum is the subject of this morphological study. The new find from the Biele Karpaty Unit, is preserved on the soles of turbiditic sandstones within the Upper Cretaceous and Eocene turbiditic sequence of the Svodnice Formation in the Biele Karpaty Mountains, Slovakia. The morphological study of the trace fossil is based on this and the available published individuals of Radhostium. The burrow reveals a regular morphological system consisting of cylindrical U-shaped shafts (elements) arranged in a row linked by a horizontal burrow. Morphology shows that the trace fossil most likely corresponds to an open burrow system of domichnion without back fill. This morphology indicates that it is essentially a branched burrow and does not represent the chevron structure typical for trace fossils of molluscs. However, this morphology is comparable to no known form, so the producer of the trace fossil cannot be reliably determined. Referred ichnospecies of Radhostium have been recorded in three geographic regions (Alps, Carpathians, Apennines). All specimens of R. carpaticum occur in Upper Cretaceous and Palaeocene turbiditic deep-marine sequences. Thus, Radhostium occurs within a relatively narrow stratigraphic range in interconnected palaeogeographic areas in the Western Tethys.