A NEW OCCURRENCE OF PARASITIC PITS IN CRINOIDS FROM THE UPPER JURASSIC OF POLAND AND ARANGE EXTENSION FOR THE ICHNOGENUS TREMICHNUS IN CYRTOCRINID HOSTS IN CENTRAL EUROPE

Parasitic endoskeletal pits, often associated with pathological swelling reactions in echinoderm hosts, are known as the ichnogenus Tremichnus and have been reported from the Middle Ordovician to the Late Jurassic. Whereas Tremichnus is common in crinoid hosts throughout the Paleozoic, there are few examples reported from Mesozoic faunas, with most described specimens representing infested Middle Jurassic millericrinid taxa. The present study describes a new occurrence of Tremichnus-bearing crinoids from the Upper Jurassic (Callovian-Oxfordian) of southwestern Poland. One pluricolumnal of Callovian age, possibly belonging to an undetermined millericrinid (potentially Apiocrinites sp.), and three calyxes of the cyrtocrinid Eugeniacrinites cariophilites of Oxfordian age preserve parasitic pits. The stem contains a single pit, which is associated with severe swelling, and represents the second-youngest example of infested millericrinid material globally and the youngest infested material from central Europe. The calyxes are only slightly swollen, with each specimen bearing a single pit except for one calyx that contains two pits on opposing sides. This material represents the second-youngest example of Tremichnus globally, and the youngest currently known example of infested calyx material, infested cyrtocrinid specimens, and infested crinoids from central Europe. These pit-bearing crinoids contribute to the sparse record of post-Paleozoic Tremichnus occurrences and allow geologic range extensions to be recognized for parasitic interactions involving certain skeletal regions and host taxa.