 It was originally described by Claypole as "Brontichthys clarki" in 1894.As "Brontichthys" is a junior synonym of "Titanichthys", it should not be confused with another, similarly-named arthrodire, "Bruntonichthys" of Dunkleosteidae.This Cleveland Shale species has an infragnathal as large as that of "T. clarkii", though "T. rectus"' infragnathal is much straighter, and does not have a spatula-like process on its anterior end.