Mawsoniidae is an extinct family of prehistoric coelacanth fishes which lived during the Triassic to Cretaceous periods.

Members of the family are distinguished from their sister group, the Latimeriidae (which contains the living coelacanths of the genus Latimeria) by the presence of ossified ribs, a coarse rugose texture on the dermatocranium and cheek bones, the absence of the suboperculum and the spiracular, and reduction or loss of the descending process of the supratemporal.

Unlike Latimeriidae, which are exclusively marine, Mawsoniidae were also native to freshwater and brackish environments.

[2][3] Species of Mawsonia and Trachymetopon are known to have exceeded 5 metres in length, making them among the largest known bony fish to have ever existed.

[5]Atacamaia Luopingcoelacanthus Yunnancoelacanthus Chinlea Parnaibaia Trachymetopon Lualabaea Axelrodichthys Mawsonia