Late Silurian fish microfossils from an East Baltic-derived erratic from Oosterhaule, with a description of new acanthodian taxa

Abstract

Fish microfossils were extracted from an erratic. The taxa from the rich microvertebrate fauna of late Pridolian (latest Silurian) age (P punctatus Zone) are listed. A full description is given of two new Gomphonchus taxa, G. mediocostatus and G. boekschoteni. On the basis of old and new material, 'Gomphonchus hoppei' is redescribed, interpreted as a porosiform poracanthodid, and assigned to Gomphonchoporus gen. nov. This interpretation ecessitates redefinition of the Poracanthodidae VERGOOSSEN 1997 to include scales without a pore-canal system. The type genus, Poracanthodes, is redefined to include only punctatiform poracanthodids sensu Vergoossen 1997. Discovery of previously undescribed scale forms of the type species, P. punctatus BROTZEN 1934, results in an extended diagnosis for this biozonal index fossil. A new poracanthodid genus, Radioporacanthodes, is erected for the porosiform poracanthodids sensu Vergoossen 1997, with type species R. porosus (BROTZEN) 1934 s.s. Brief palaeontological and distributional comments on other microvertebrate taxa from the list are included, as well as a section on the biostratigraphical and correlational implications of the present and similar faunas from erratics for the East Baltic standard succession.