Nanostructures in Palaeozoic linguloid brachiopods

SEM studies of untreated and uncoated fracture sections of the linguloid brachiopods Obolus ruchini Khazanovitch & Popov and Bicarinatina bicarinata Kutorga from the Cambrian of NW Russia and Devonian of Estonia, respectively, revealed fibril-like nanostructures, less than 200 nm in diameter. These structures are interpreted here as phosphatised biopolymers that were not mineralised in vivo and may have supported the apatite mineralisation from the early stages of the formation of bacula. Previous documentation of nanostructures in Palaeozoic fossils is quite rare.