Revision of the actinopterygian genus Mimipiscis (=Mimia) from the Upper Devonian Gogo Formation of Western Australia and the interrelationships of the early Actinopterygii

Abstract

ABSTRACTThe Devonian actinopterygian Mimia Gardiner & Bartram (1977) of the Upper Devonian (Frasnian) Gogo Formation of Western Australia, one of the most completely known of all Palaeozoic ray-finned fishes, is renamed Mimipiscis nom. nov. due to preoccupation of the former genus by the butterfly Mimia Evans (1953). Recently acquired data, including the description of newly prepared fossil material, has revealed the presence of a second species in this formerly monotypic genus, as well as previously unreported features of the tail, parasphenoid and ontogenetic variability of type species, Mimipiscis toombsi (Gardiner & Bartram 1977). The second form, Mimipiscis bartrami sp. nov., differs from the contemporary M. toombsi in details of the body shape, squamation, snout, suboperculum and parasphenoid. Phylogenetic analyses recover Mimipiscis and Gogosardina as sister genera within a monophyletic Mimiidae, a clade restricted to the Late Devonian of Western Australia.