Cladichnus parallelum isp. nov.: a mid- to deep-tier feeding burrow system

The ichnospecies Cladichnus parallelum consists of upper components characterized by downward branching, decreasingly inclined tubes, and lower components having horizontal, long, parallel tubes formed in the laminated part of a muddy, marly turbidite. The tubes of both components were successively produced, and the lower ones display an annulated fill. The producers of Cladichnus exhibit thigmotactic and phobotactic behavior in that the tubes are regularly spaced apart, do not cross over- or cross-cut, and their orientation is related to the fabric of the turbidite. The tube fill of both components is enriched in terrigenous material and organic matter suggesting selective feeding on the sediment surface, and the tubes do not show any grain sorting around them. The strong compression of the horizontal tubes suggests that the fill initially had high porosity. The producer of Cladichnus parallelum probably took advantage of burrowing in an anoxic setting; microbes likely played a role in converting organic material stored within the tubes or in processing dissolved compounds drained into the highly porous tubes.