A new graptolite (Pterobranchia) from the early Cambrian Xiaoshiba Lagerstätte of China

Five Yunotubus specimens from the approximately 516 Ma Hongjingshao Formation provide a diagnostic early Cambrian pterobranch minimum, not a Pterobranchia origin date or proof that every older tube fragment belongs to the clade.

Yunotubus directly records a pterobranch colony in the approximately 516 Ma Xiaoshiba Lagerstätte of Yunnan; this locality sample does not establish a complete early Cambrian or global pterobranch distribution.

Yunotubus combines fusellar tubes, zooids and a connecting stolon recovered within Pterobranchia by sampled morphology matrices, while that placement remains a scored phylogenetic hypothesis rather than observed ancestry.

Yunotubus preserves colonial zooids connected by a stolon inside fusellar tubes, whereas living Rhabdopleura supplies direct tentacle and ciliary anatomy; the traits come from different sampled taxa and times.

The Graptolithina root display uses 516–0 Ma as a sampled envelope from diagnostic Yunotubus material in the approximately 516 Ma Hongjingshao Formation to living rhabdopleurid graptolites; it is not a graptolite origin date.

The 516–0 Ma Hemichordata route is anchored by the approximately 516 Ma Yunotubus pterobranch sample and living Rhabdopleura observations; it is a represented-lineage span, not the phylum’s origin or a global hemichordate FAD.