Pieninia oblonga - Skeletal parts or endoparasites of keratosa sponges?

The problematic bodies Pieninia oblonga Borza & Misik common in Barremian t o Upper Eocene shallow-water sediments were considered as algae, rudist fra gments, echinoderm remains, or sclerites of Gorgonaceae. They were recently found inside the skeleton of sponges, probably Keratosa. The growth stages of these bodies are described. The question remains whether they are unusu al sclerites or parasites. The way of their loosening from the skeletons wa s not observed.