Lepeichnus giberti igen. nov. isp. nov. from the upper Miocene of Lepe (Huelva, SW Spain): Evidence for its origin and development with proposal of a new concept, ichnogeny

A new ichnotaxon, Lepeichnus giberti igen. nov. isp. nov., is described from sandy silts and sands of the upper Miocene (Tortonian–Messinian) of the Quadalquivir Basin (Lepe, Huelva, SW Spain). It is a complex bioturbation structure consisting of two vertical shafts interconnected by a horizontal C-shaped gallery, which in turn exhibits a hook-shaped branch. L. giberti is interpreted as probably produced by a crustacean that could have combined dwelling, deposit feeding and farming strategies in a shallow-marine environment. Its architectural similarities with modern upogebiid burrows suggest the record of a new burrowing behavior, not yet known today, for this group of mud shrimps. The large number of studied specimens and their exceptional degree of preservation allow proposing the new concept of ‘ichnogeny’, as a tool to describe the origin and development of a modern or fossil boring or burrowing trace.