The revision of "Cladodus" occidentalis, a late Palaeozoic ctenacanthiform shark

The teeth of a well known late Palaeozoic cladodont chondrichthyan, "Cladodus" occidentalis from Russia, USA, and England are restudied and a new generic name, Glikmanius gen. nov., is proposed for this species. Yet another tooth-based species, formerly described as ?Symmorium myachkovensis, occurring on the Russian Platform and in Nebraska, is considered to belong to the newly erected genus. Although there is no direct evidence that Glikmanius possessed fin spines, the broad similarity between its teeth and those of Ctenacanthus compressus suggests it had a ctenacanthiform affinity. The possible relationships between Glikmanius, Cladodus sensu stricto, "Ctenacanthus" costellatus, and Heslerodus, are suggested. However, the proposition put forward by an earlier author that the teeth of Heslerodus might represent the lower jaw dentition of G. myachkovensis, is rejected. The overall resemblance of Glikmanius teeth and those of Cladoselache and Squatinactis is recognised as convergent.