Crustacean microcoprolites from Jurassic (Oxfordian) hydrocarbon-seep deposits of Beauvoisin, southeastern France

Decapod crustaceans are the most conspicuous predators and scavengers of modern chemosynthesis-based ecosystems at hydrothermal vents and hydrocarbon seeps; however, very little is known about decapod crustaceans at ancient seeps or vents. Some decapods, including galatheids, are known to produce highly specific, internally structured microcoprolites. Late Jurassic (Oxfordian) hydrocarbon-seep limestones from Beauvoisin (southeastern France) were found to contain such microcoprolites including Favreina fontana n. isp., F. cf. martellensis Brönnimann and Zaninetti, Palaxius salataensis Brönnimann, Cross and Zaninetti and Palaxius isp. These diverse ichnofossils indicate that crustaceans were also a part of ancient chemosynthesis-based ecosystems. This is the first report of crustacean coprolites from a deep-water environment.