Atubaria

The genus Atubaria is a type of pterobranch, which are small marine invertebrates belonging to the phylum Hemichordata. Pterobranchs are typically found in the Southern Hemisphere, though some species inhabit northern waters.1

Their bodies are divided into three parts: a proboscis, a collar with tentacles for filter-feeding, and a trunk containing a U-shaped gut. Unlike the other two pterobranch genera, Rhabdopleura and Cephalodiscus, which form colonies in secreted tubes, Atubaria lives on hydroids. All pterobranch species are considered rare, with about 21 described species in total. Pterobranchs may have evolved from extinct marine animals known as graptolites.1