The evolutionary relationships of the earliest known cycloneuralians and a new record from the Cambrian Fortunian of South China

Three Indeterminate Forms of Scalidophoran Worms from the Cambrian Fortunian of South China

“…In terms of Fortunian scalidophoran worms, pores have also been observed in Eopriapulites (Shao et al, 2020b, fig. 6; described as -pits‖) and Xinliscolex intermedius (Zhang, 2022, fig. 2F), while tubules have been observed in X. intermedius (Zhang, 2022;figs.…”

“…6; described as -pits‖) and Xinliscolex intermedius (Zhang, 2022, fig. 2F), while tubules have been observed in X. intermedius (Zhang, 2022;figs. 3E, 4C-E).…”

“…The Fortunian scalidophorans already have a relatively high diversity, with 7 genera and species and 10 indeterminate forms now reported. They can be divided into three categories based on the type of annuli: (1) worms with microannuli, which are dense and numerous, similar to priapulid-like forms, including Eopriapulites (Liu et al, 2014;Shao et al, 2020b) and Xinliscolex (Zhang, 2022); (2) worms with macroannuli that are wider and resemble kinorhynch-like forms, including Eokinorhynchus (Zhang et al, 2015), Zhongpingscolex (Shao et al, 2020a), Qinscolex, Shanscolex (both in , Dahescolex (Shao et al, 2020b), forms 1-3 and Based on the characteristics of the annulus, there may be a closer affinity between Eopriapulites and Xinliscolex. Likewise, there may be closer affinities between form 3 sensu Liu et al, 2019, worm A and other kinorhynch-like forms.…”

“…Scalidophorans are rare components of small-shellyfossil assemblages in the Lower Cambrian Kuanchuanpu Formation (Fortunian Stage) in Zhangjiagou Lagerstä tte, Xixiang County, Shaanxi Province, South China. To date, seven scalidophoran genera and species, as well as eight indeterminate forms, have been reported in this stage, and recent reports on new types of fossil scalidophorans (Liu et al, 2014(Liu et al, , 2019Zhang et al, 2015Zhang et al, , 2018Shao et al, 2016Shao et al, , 2018Shao et al, , 2020aZhang, 2022) imply a higher diversity in this stage. As the earliest unambiguous fossils of scalidophorans, these fossils are of great significance for understanding the origin and early evolution of Cycloneuralia and Ecdysozoa (Wang et al, 2019(Wang et al, , 2020.…”

A priapulid larva from the middle Cambrian (Wuliuan Stage) of North Greenland (Laurentia)

“…The oldest priapulidlike worm, Eopriapulites Liu & Xiao, 2014in Liu et al (2014, and other scalidophoran worms were described from the early Cambrian (For tunian) of China by Liu et al (2014Liu et al ( , 2019, Shao et al (2016a, b;2020a, b) and Zhang (2022). Yang et al (2016) noted 17 species assigned to 16 genera from the Chengjiang Lagerstätte (Cambrian Series 2) of southern China and five species referred to five genera from the middle Cambrian (Miaolingian Series) Burgess Shale of British Columbia (Conway Morris 1977, Briggs et al 1994, Vannier 2012, Smith et al 2015.…”