Trachymetopon
Trachymetopon is an extinct genus of prehistoric coelacanth from the Early Jurassic Posidonia Shale of Germany and the Middle Jurassic of France. Only one species has been named, "Trachymetopon liassicum", described by Henning in 1951 from an almost complete specimen found in the Lower Toarcian of Ohmden in Baden-Württemberg. Another specimen is known from the same site, and two older specimens come from the Sinemurian of Holzmaden. The holotype of this species is in length. A giant specimen of an undetermined species of "Trachymetopon" is known from the Middle Jurassic (Late Callovian) of Normandy. This specimen, composed of  a 53 cm long palatoquadrate, belongs to an individual in length. A study published in 2015 revealed that this coelacanth belongs to the Mawsoniidae. "Trachymetopon" is one of the few known mawsoniids to have been exclusively marine (with an indeterminate form from the Triassic of France), while most of the other members of the group have lived in fresh and brackish waters. Phylogeny. A phylogenetic analysis of the mawsoniids published in 2020 found a polytomy grouping together "Trachymetopon" and the Cretaceous genera “"Lualabaea"”, "Axelrodichthys", and "Mawsonia". The genus “"Lualabaea"” could be congeneric with "Axelrodichthys".