Alternating stripmining and sequestration in deep-sea sediments: The trace fossil Polykampton - an ecologic and ichnotaxonomic evaluation

Polykampton Ooster, 1869, comprises deep-sea trace fossils composed of a horizontal median cylindrical tunnel and lateral spreite lobes that alternate on either side of the tunnel and are slightly inclined to bedding. The lobes in P. alpinum Ooster, 1869, are closely spaced and partly shingled. In P. guberanum isp. nov. they are asymmetric and widely spaced. In both ichnospecies, the lobes are generally below the median tunnel. In P. multiflabellatum isp. nov., the lobes extend from outer bents of the median tunnel that runs below the lobes. Polykampton is a structure produced by a "worm"-like organism occupying a deep endobenthic tier. The tracemaker evidently sequestered organic-rich sediment from the seafloor, stored it in the lobes and processed it later by stripmining for feeding, especially in times of low food availability on the seafloor. Polykampton occurs in upper Albian to Oligocene deep-sea, mainly turbiditic deposits.