Pyritized preservation of chancelloriids from the Cambrian Stage 3 of South China and implications for biomineralization

The enigmatic Cambrian animal chancelloriids were discovered in a wide range of taphonomic settings; however, preservation biomineralized sclerite microstructure was solely known from secondarily phosphatized skeletal remains. Here, we investigate uniquely pyritized chancelloriid the lower Guojiaba Formation southern Shaanxi Province, China, using combination advanced analytic techniques. Results energy dispersive spectroscopy (EDS), X-Ray Fluorescence (XRF), and Raman spectrum show that sclerites scleritomes are preserved as internal moulds with calcitic outer layer. layer enveloping likely represents recrystallized counterpart original wall. Distinctive fibrous microstructures sclerites, which echo features seen fossils chancelloriids. typical microstructure, along calcite, corroborate interpretation originally constructed by aragonite. stability mineral composition both carbonate siliciclastic backgrounds indicate adapted to exploit aragonitic fibres build their skeletons regardless change living environments.