The Fish Trail Undichna quadrisulcata isp. nov. from the Eocene of Spitsbergen

Undichna quadrisulcata isp. nov. is described from the Eocene of Spitsbergen, where it occurs together with xiphosuran (horseshoe crabs) traces in upper shoreface to foreshore deltaic sandstone. This is the first record of a marine (deltaic) Undichna from the Eocene. The trail consists of two or three pairs of paralleling sinusoidal grooves (in epirelief) or ridges (in hyporelief). Previous records of this trace fossil from the Carboniferous and Permian were assigned to U. insolentia Anderson, 1976, which, however, comprises a more complex pattern. The repeated occurrence of U. quadrisulcata isp. nov. in the Carboniferous, Permian, Triassic and Eocene, independent from U. insolentia, justifies its own ichnospecies name and suggests a different kind of producer. U. quadrisulcata isp. nov. is interpreted as a fish trail, probably produced by a representative of Amiiformes (actinopterygian, ray-finned fish) or coelacanth fish.