Life strategies of Early Cambrian brachiopods on mud substrate:Inferences from the Chengjiang fauna of South China

Aim To infer the life strategies of Early Cambrian brachiopods on muddy substrate from the brachiopods in the Chengjiang fauna of Yunnan,China.Methods Based on observation of a number of specimens of 8 genera,several collusions are reached.Results Studies of the early Cambrian Chengjiang brachiopods suggest that several types of relationship of Cambrian brachiopods with the substrate where they inhabited,including pedicle-anchoring,free-lying,cemented epifaunal,semi-infaunal,of which attachment by a pedicle to the substrate was probably the commonest.Conclusion An analysis of the structure of fossil brachiopod communities in the Chengjiang soft-muddy substrate demonstrate that the Chengjiang brachiopod taxa,although inhabiting the same environment,could have occupied quite distinct tiers of space and ecological niche:Diandongia had a semi-infaunal mode of life,with its pedicle buried in sediment,and ventral valve lay on the sea bottom,and Heliomedusa was free-lying,but the coeval brachiopod genus Xianshanella and Longtancunella and Kutorgina tended to elevate its feeding structure through their stout pedicle to a higher level above the sea bottom.At the same time,the Lingulellotreta and Linguella was possibly suspended above turbulence at the sediment-water boundary.