Growth pattern of Fortunian scalidophoran sclerites

Fortunian scalidophoran worms have shown high diversity, with 7 genera and species and 10 indeterminate forms. Current studies have mainly focused on morphology as well as early evolution, and studies on ontogeny have not been carried out due to the limited number of specimens. Here, we report new material of an Orsten-type preserved Indeterminate Form 3 from the Zhangjiagou section. Collected specimens of Indeterminate Form 3 with different annulus widths indicate the presence of several ontogenetic stages. We found newly formed sclerites on the annulus of Indeterminate Form 3 at different ontogenetic stages, suggesting that the sclerites of Indeterminate Form 3 become more numerous in addition to increasing in size during growth. The size of the large sclerites may also increase as the worms grow, however, their number may not change

Data from: Diversity of cnidarians and cycloneuralians in the Fortunian (early Cambrian) Kuanchuanpu Formation at Zhangjiagou, South China

The latest discovery of microfossils from lower Cambrian (Fortunian Stage) Zhangjiagou Lagerstätte in South China are presented. This lagerstätte is rich in exceptionally preserved microfossils, including embryos of Olivooides multisulcatus, Olivooides mirabilis, and Pseudooides prima, hatched stages of O. multisulcatus, O. mirabilis, Hexaconularia sichuanensis and Quadrapyrgites quadratacris, and cycloneuralians represented by Eopriapulites sphinx and a new form. The largest known fragment of O. mirabilis implies that its adults length can be more than 9.0 mm with at least 50 annuli, and the longest known specimen of Q. quadratacris has at least 18 annuli. These unusually large specimens refute the non-feeding larvae hypothesis for Olivooides and Quadrapyrgites. New material documented here includes two new types of fossil embryos, one with hexaradial symmetry and the other with octaradial symmetry, as well as a new cycloneuralian with two tail spines. Based on the current material, it is inferred that 1) early cnidarians have a high diversity in the Fortunian Stage; 2) P. prima might represent the embryonic stages of H. sichuanensis; 3) adults of Olivooides and Quadrapyrgites may have reached centimeter scale dimensions with more than 50 annuli; 4) Olivooides and Quadrapyrgites may be better interpreted as coronate scyphozoans; 5) cycloneuralians also had a high diversity in the Zhangjiagou Lagerstätte; and 6) cycloneuralians might have originally been part of the early Cambrian meiofauna rather than belonging to the macrobenthos. Such ancestral cycloneuralians might have been Eopriapulites-like, possessing pentaradially symmetric, backward pointing, and internally hollow introvert scalids used as locomotory devices

Appendix S3

Appendix S3. Micro-CT movie of the holotype UMCU 14CHD0618-006 of Qinscolex spinosus gen. et sp. nov. Slice images parallel to the transverse plane, starting from the anteriormost part

Shaoetal_SupplementaryData

This file contains four data matrices for the phylogenetic analyses in Shao et al

Appendix S5

Appendix S5. Micro-CT movie of the holotype UMCU 15CHD0819-009 of Shanscolex decorus gen. et sp. nov. Slice images parallel to the transverse plane, starting from the anteriormost part

Data from: New armoured scalidophorans (Ecdysozoa, Cycloneuralia) from the Cambrian Fortunian Zhangjiagou Lagerstätte, South China

Although molecular studies estimated that cycloneuralians might have originated in the Ediacaran Period and diversified in the early Cambrian, it was not until 2014 that they were first reported from the Cambrian Fortunian Stage. To date only two species and five indeterminate forms have been described. Here, we report new three‐dimensionally phosphatized microfossils of cycloneuralians from the Fortunian Zhangjiagou Lagerstätte, South China. Two new genera and species, Qinscolex spinosus gen. et sp. nov. and Shanscolex decorus gen. et sp. nov., and Indeterminate Forms 1–7 are described and tentatively assigned to total‐group Scalidophora, greatly increasing the diversity of the Fortunian cycloneuralians. These Fortunian cycloneuralians have diverse cuticular spines, plates, and spinose sclerites of various sizes on the trunk, thus assignment of co‐occurring fragmented trunk parts or disassociated spines or sclerites to a specific species is currently impossible. Some of the Fortunian cycloneuralians might have reached a centimetre in length; they may have been temporary meiobenthos in their juvenile or younger adult stages, only joining the macrobenthos when they reached macroscopic dimensions. It is proposed that an introvert with hexaradially symmetric and internally hollow scalids might be the plesiomorphic state for cycloneuralians

Appendix S6

Appendix S6. Micro-CT movie of the holotype UMCU 15CHD0819-009 of Shanscolex decorus gen. et sp. nov. Slice images parallel to the anterior-posterior body axis

Appendix S4

Appendix S4. Micro-CT movie of volume rendition of the holotype UMCU 15CHD0819-009 Shanscolex decorus gen. et sp. nov

Data from: New armoured scalidophorans (Ecdysozoa, Cycloneuralia) from the Cambrian Fortunian Zhangjiagou Lagerstätte, South China

Although molecular studies estimated that cycloneuralians might have originated in the Ediacaran Period and diversified in the early Cambrian, it was not until 2014 that they were first reported from the Cambrian Fortunian Stage. To date only two species and five indeterminate forms have been described. Here, we report new three‐dimensionally phosphatized microfossils of cycloneuralians from the Fortunian Zhangjiagou Lagerstätte, South China. Two new genera and species, Qinscolex spinosus gen. et sp. nov. and Shanscolex decorus gen. et sp. nov., and Indeterminate Forms 1–7 are described and tentatively assigned to total‐group Scalidophora, greatly increasing the diversity of the Fortunian cycloneuralians. These Fortunian cycloneuralians have diverse cuticular spines, plates, and spinose sclerites of various sizes on the trunk, thus assignment of co‐occurring fragmented trunk parts or disassociated spines or sclerites to a specific species is currently impossible. Some of the Fortunian cycloneuralians might have reached a centimetre in length; they may have been temporary meiobenthos in their juvenile or younger adult stages, only joining the macrobenthos when they reached macroscopic dimensions. It is proposed that an introvert with hexaradially symmetric and internally hollow scalids might be the plesiomorphic state for cycloneuralians