Symbiotic endobionts in tabulate corals from the Late Ordovician and Silurian of Estonia

Four new symbiotic associations between worms and tabulate corals have been described from the Hirnantian to Ludfordian of Estonia. Chaetosalpinx csp. occurs in Palaeofavosites porkuniensis from the Hirnantian of northern Estonia. Chaetosalpinx ferganensis occurs in Favosites hisingeri from the Telychian, with an infestation rate of about 18%. Chaetosalpinx siberiensis occurs in the Favosites forbesi from the Ludfordian of Estonia, with an infestation rate of about 33%. Endobiotic Cornulites sp . was discovered from the Ludfordian Favosites terrae-novae. Our data suggest that Chaetosalpinx trace makers exhibited a significantly broader parasitic behavior, infesting a wider variety of coral species during the Silurian in the Baltica. The discovery of cornulitid within the corallum of Favosites indicates that the symbiotic relationship between cornulitids and tabulates spanned a broad stratigraphic range, extending from the late Katian to the Ludfordian during the early Paleozoic in Estonia.