What’s it about?
The authors look closely at the characteristics that distinguish osteichthians from other jawed fishes. They then review materials from fossil groups of fishes, in particular the Acathodii, and score them for the same characters. The result of their analysis is that they place the Acathodii as basal osteichthians, a sister group to the crown osteichthian groups, the Actinopterygii and the Sarcopterygii.
Why does it matter?
There is substantial debate about where acanthodians lie in the evolutionary history of vertebrates. They have been viewed now as a separate sister group from crown gnathostomes (Chondrichthyes plus Osteichthyes), as basal chondrichthians and as basal osteichthians. This research contributes to this debate, but does not resolve it (see Coates et al., 2018 and Zhu et al., 2016).
Why did I read this?
This paper was selected as required reading for my vertebrate paleontology class during the ‘survey of jawed fishes’ unit.
What did I learn?
Between this paper and many others that I’ve read these past couple of weeks, I’ve learned that the relationships among fossil jawed fishes are far from resolved, and are quite interesting.