Three Cambrian fossils assembled into an extinct body plan of cnidarian affinity

Eighty-five new specimens plus type material unite three named forms as Xianguangia. Ou et al. recover a suspension-feeding stem-cnidarian body plan, whereas Zhao et al. recover Dinomischidae on the ctenophore stem in their main Bayesian analysis and a polytomy under alternative coding.

Xianguangia reconstruction is based on 85 new specimens plus type material, yet column, tentacle and phylum-level interpretations remain disputed; the Chengjiang sample is not a cnidarian global first appearance.

Xianguangia is displayed at 518–518 Ma only as the age-bounded Chengjiang specimen sample assessed by competing body-plan interpretations; it is not a crown-anthozoan FAD, direct ancestor or global genus duration.

Xianguangia sinica has competing phylogenetic placements: Ou et al. recover a stem-cnidarian body plan, whereas Zhao et al. recover Xianguangia, Daihua and Dinomischus as Dinomischidae on the ctenophore stem in their main Bayesian analysis, with a polytomy under alternative coding; neither placement is treated as definitive here.

The profiled Xianguangia material is from the Chengjiang biota of Yunnan, China; this exceptional deposit records the sampled occurrence and does not establish a complete distribution or geographic origin.

The Xianguangia reconstruction infers suspension feeding from its tentaculate body plan in a marine Chengjiang setting, while attachment, movement and population-wide ecology are not directly observed.

The expanded Xianguangia sample preserves a tentacle-bearing crown and central column-like region in the published reconstruction, but the column’s identity is revised as tentacular anatomy in later primary work.