Symbiotic worm endobionts in a stromatoporoid from the Rhuddanian (Early Silurian) of Hiiumaa, Estonia

Multiple bioclaustrations identified as possible Chaetosalpinx are reported from a stromatoporoid of Rhuddanian age from Hiiumaa Island, Estonia. This is the second record of symbiotic worm endobionts from the end-Ordovician mass extinction recovery fauna of Estonia. The end-Ordovician mass extinction did not terminate complex ecological relationships between at least some worm endobionts and their hosts.