Figure 1 Geological map and stratigraphic column. 1 , geological map of the Yangtze Gorges and surrounding region, showing the fossil locality (arrow) at Wangzishi in Hubei Province, modified from Jiang et al. (2012 ); 2 , stratigraphic column of the Shuijingtuo Formation at Wangzishi

Fig. 5. Artist reconstructions of Duplapex anima gen. et. sp. nov. ( a ) The new Tuzoiidae from the Shuijingtuo Formation (Cambrian Stage 3), Hubei, China. Carapace covering soft body, folded dorsally, with reticulate ornamentation. Valve bent inwards, forming two layers. Doublure wide

Fig. 1. Locality map of the Qingjiang biota and stratigraphy of the Shuijingtuo Formation in the Jinyangkou Section (modified from Fu et al. 2019 , p. 1339, fig. 1). ( a ) Major fossil Lagerstätten similar to the Cambrian Burgess Shale in southern China. Tuzoia has been found in all

Fig. 4. Duplapex anima gen. et. sp. nov. from the Jinyangkou Section, Shuijingtuo Formation (Cambrian Stage 3), Changyang County, Hubei Province, China. ( a ) Specimen JY0738A, two valves fragmented, preserved in ‘butterfly’ orientation, with a wide doublure and an annulated left eye stalk

Fig. 3. Duplapex anima gen. et. sp. nov. from the Jinyangkou Section, Shuijingtuo Formation (Cambrian Stage 3), Changyang County, Hubei Province, China. Specimen JY0748A, holotype. ( a ) Two valves, folded dorsally, bent inwards at the ventral margin, formed outside and inside layers (doublure

-Pb ages in Shuijingtuo Formation are from Okada et al. (2014) , and those in Doushantuo Formation are from Condon et al. (2005) .

) and Wu et al. ( 2021 ). Geochronometric data sources: Condon et al. ( 2005 ) and Yang et al. ( 2021 ) for the lower Doushantuo Formation and Miaohe Member; Huang et al. ( 2020 ) and Zhang et al. ( 2022 ) for the Baimatuo Member; Okada et al. ( 2014 ) for the Cambrian Shuijingtuo Formation. Cry

Figure 2 SEM micrographs of sponge spicules, hyolithelminths, and linguliformean brachiopods that co-occur with embryo fossils in the upper Shuijingtuo Formation. 1 , triaxonal hexactinellid sponge spicule, sample 11-WZS-0.6; 2 , hexactinellid sponge spicule similar to Taraxaculum Bengtson

Formation (including the Miaohe Member), Baimatuo Member and Shuijingtuo Formation are from Condon et al. (2005) , Huang et al. (2020) and Okada et al. (2014) , respectively. The alternative correlations of the Miaohe Member with Member IV of the Doushantuo Formation ( Xiao et al. 2017 ; Zhou

& Zhang ( 2015 ). The dotted lines represent the lithostratigraphic boundaries. KY – Kunyang Group; NT – Nantuo Formation; ZJQ – Zhujiaqing Formation; KCP – Kuanchuanpu Formation; YJH – Yanjiahe Formation; SJT – Shuijingtuo Formation; JC – Jiucheng Member; DB – Daibu Member; GJS – Gaojiashan Member; Fm

solid columns that connected the laminae; ( 6, 7 ) latex casts of ( 2, 3 ) showing the secondary columnar structure of an acrotretoid from the Shipai Formation (siliciclastic deposits); ( 8, 9 ) secondary columnar structure of an acrotretoid from the Shuijingtuo Formation (carbonate deposits) showing

– Cambrian; ε – Cambrian; Cryog. – Crogenian Period; E – Ediacaran; G – Guojiaba Formation; GJS – Gaojiashan Member; HMJ – Hamajing Member; K – Kuanchuanpu Formation; LGL – Lieguliu Formation; MDP – Maidiping Formation; SJT – Shuijingtuo Formation; Shuram Ex – Shuram Excursion; XHP – Xihaoping Member; YJH

Wawrmast Formation Morocco Streng, 1999 Almohadella braunae range 2–3 middle Cambrian Jbel Wawrmast Formation Morocco Streng, 1999 Eohadrotreta zhenbaensis average 2.5 lower Cambrian Shuijingtuo Formation South China Z.L. Zhang et al., 2016 Lingulida: Linguellotreta sp

Figure 5. SEM images of acrotretoid Linnarssonia sapushanensis n. sp. from the Wulongqing Formation (Series 2, Stage 4) at Sapushan and Shijiangjun sections of Yunnan Province, and comparison to Eohadrotreta zhenbaensis Li and Holmer, 2004 from the Shuijingtuo Formation of Hubei Province

. A triangular rigid framework formed by NaQ grains is filled with porous migrabitumen suggesting that the NaQ grains effectively resisted the effects of mechanical compaction (sample DY5-03). (C) The SEM image of an Shuijingtuo Formation (SJT) organic-rich mudstone sample ( TOC = 8.14 wt. %; EqVR o = 2.39

) Shuijingtuo Formation (SJT) mudstone sample containing abundant DeQ grains and other detrital minerals, including K-feldspar (K-F) (sample YY1-26). (D) Scanning electron microscopy (SEM) image of an LMX mudstone sample dominated by angular DeQ grains and clay (sample PS1-13). The SEM (E