Pterobranchia is a clade of small, worm-shaped animals. They belong to the hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 30 known living species in the group.

Pterobranchia were established by Ray Lankester in 1877. It contained, at that time, the single genus Rhabdopleura. Rhabdopleura was at first regarded as an aberrant Polyzoon, but with the publication of the Challenger Report (Cephalodiscus) in 1887, it became clear that Cephalodiscus, the second genus now included in the order, had affinities in the direction of the Enteropneusta.

It has been suggested that pterobranchs are the closest living cousins of the extinct graptolites.

References

• At Billie Swalla's site
• Cameron, C. B. Classification of the extant hemichordata

Hemichordates | 1911 Britannica

Flügelkiemer | Pterobranchier | Pióroskrzelne | Krídložiabrovce