多鳃鱼 / Polybranchiaspis

My many gill openings remind you that breathing equipment had a long history before human noses!
我的许多鳃孔提醒你：在人类鼻子出现以前，呼吸装备已经有很长的历史啦！

Sources
Internal anatomy of the polybranchiaspids (Agnatha, Galeaspida)
https://www.nature.com/articles/282833a0
Mass extinction triggered the early radiations of jawed vertebrates and their jawless relatives (gnathostomes).
https://www.science.org/doi/10.1126/sciadv.aeb2297
Species reference
https://en.wikipedia.org/w/index.php?search=Polybranchiaspis

Research context
Polybranchiaspis represents the diversity of armored jawless fishes. Comparing its gill openings and head shield with other galeaspids helps reconstruct the anatomical background from which jawed vertebrates emerged.