Phycosiphon (Fischer-Ooster, 1858)

DESCRIPTION: Irregularly meandering burrows with extensive small-scale spreiten that produce repeated narrow, U-shaped lobes extending from a central tunnel. Lobes are parallel or oblique to bedding. Commonly appears as a light-colored halo (spreiten) around a small dark, organic-rich core (tunnel).

BEHAVIOR(S): Fodinichnia (deposit feeding)

ENVIRONMENTAL SETTINGS: Fully marine.

POSSIBLE TRACEMAKERS: Veriform organism.

GEOLOGIC RANGE: Cambrian–recent

ADDITIONAL REFERENCES: Emended from Crimes 1992, Wetzel and Bromley 1994, Uchman 1998, Hammersburg et al. 2018.

REMARKS: Can be confused with Helminthopsis, which does not have a halo around the dark, sinuous tunnels.