Published online by Cambridge University Press: 24 August 2017
Some rare microscopic cycloneuralians are present in the Cambrian of South China, represented by Eopriapulites and Eokinorhynchus (both early Cambrian), fossil embryos of Markuelia (middle to late Cambrian), and palaeoscolecids (early to late Cambrian). Among them, palaeoscolecids are relatively diverse and abundant. Here, we describe new material of three-dimensionally phosphatized and microscopic cycloneuralians from the Paibian Stage of Wangcun Lagerstätte, western Hunan, South China. New material includes fossil embryos assignable to Markuelia sp., two other types of fossil embryos, and three species of palaeoscolecids, including Dispinoscolex decorus Duan, Dong, and Donoghue, 2012, Schistoscolex hunanensis Duan, Dong, and Donoghue, 2012, and Austroscolex sinensis new species. The palaeoscolecid fragments differ mainly in size and armor of the trunk annuli. Since Eokinorhynchus and Eopriapulites occurred the earliest among the Cambrian cycloneuralians, it is proposed here that: (1) cycloneuralians originated in the Cambrian Fortunian small shelly faunas rather than in the early Cambrian macrobenthos, (2) ancestral cycloneuralians may have simple trunk armor, and (3) Eopriapulites represents an ancestral cycloneuralian.