Suspension feeding by the pterobranch hemichordate Rhabdopleura normani

Video and electron microscopy directly document suspension feeding by millimetre-scale, tube-dwelling zooids of living Rhabdopleura normani; this sampled ecology is not projected unchanged onto fossil pterobranchs.

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 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.