The order Elopiformes includes many living fish species more commonly know as Tarpon, Tenpounders and Ladyfish. They are thought to have evolved during the middle Jurassic but lost many members during the great extinction at the end of the Cretaceous. The Palaeocene and Eocene then saw a rebuild within this group and many of the London Clay (Ypresian, Eocene), represent this period. These are predatory fish, hunting nocturnally on other midwater fish. 

There are currently 6 described species in the London Clay within this group however a number of additional unique specimens suggest significantly more diversity which I will try and showcase here.