First report that shows anaerobic sequential biodegradation of hydrocarbons. Peptococcaceae, Anaerolineaceae and Syntophaceae are possible primary degraders. Acetoclastic and hydrogenotrophic methanogens co-dominate in tailings ponds. Cometabolism might be important for biodegradation of recalcitrant compounds. It extends known range of hydrocarbons susceptible to methanogenic biodegradation.