Burrows filled with faecal pellets from the Cambrian (Stage 4) Guanshan biota of South China and their palaeoecological implications

Recent excavations of the Guanshan biota at Shijiangjun section in eastern Yunnan Province, South China, have revealed many well-defined faecal pellets and related trace fossils. These can be assigned to three morphotypes, which affinities with ichnogenera Tomaculum, Alcyonidiopsis Tubulichnium. Morphotype 1 is an unbranched burrow filled randomly distributed pellets. 2 a string-shaped without branching, containing intensely compacted 3 comprises burrows fill central cavity. The ellipsoidal morphotype Coprulus oblongus. They are morphologically similar excrements produced by modern deposit-feeding polychaetes, as well gut content early Cambrian polychaete worms (Guanshanchaeta felicia) from priapulid (Selkirkia) Xiaoshiba Lagerstätte. This analogy suggests polychaetes potential producers these that diverse range digestive methods had already been established Stage 4 ca. 510 Ma ago. interpreted storage possibly for cultivation bacteria, would represent case this behaviour. discovery suite indicates origin strategies traced back least 4.