The fossil as preserved is carbonized, and indicates an eel-shaped animal up to 6 centimetres (2 in) in length.

The skull, which must have consisted of hardened cartilage, exhibits pairs of nasal and auditory capsules, with a gill apparatus below its hinder part, and ambiguous indications of ordinary jaws.

[citation needed] The phylogeny of this fossil has puzzled scientists since its discovery in 1890, and many taxonomies have been suggested.

[1] Previously, it had been classified as a larval tetrapod, unarmored placoderm, an agnathan, an early stem hagfish, and a chimera.

[6] Hirasawa and Kuratani, who are authors in 2022 study, replied to that and reviewed phylogeny again, resulted it would be closer to Acanthostega instead.