Parasite-induced shell damage in brachiopod Porambonites (Porambonites) laticaudata from the Late Ordovician (Sandbian) of Estonia

A new type of shell damage has been described in Ordovician brachiopods in Porambonites (Porambonites) laticaudata. There is a pair of small pits with somewhat different outline in the shell surface at the anterior commissure of the brachiopod. These pits are oriented in lateral direction, about 40o from the direction of the sulcus on the anterior commissure. Previously known shell damage has resulted from failed predatory attacks by durophagous predators and differ from the shell damage in P. (P.) laticaudata. The pits in the shell margin are most likely the result of shell malformation caused by the presence of symbionts. It is plausible that the symbionts of the P. (P.) laticaudata benefitted from inhalant currents and were cleptoparasites. The symbionts caused damage to the host brachiopod, which also suggests a parasitic relationship.