Short one today,
as I continue to wrestle with ray-fin fish. It’s coming together, but slowly. Lots of corrections have been made over the last several weeks.
Figure 1. Fish skull roofs colored with tetrapod homologs. The parietal is of interest here as it splits in the wake of the post parietal, which forms a parasagittal crest in many taxa. The parietal disappears in some taxa.
Trying to figure out the cranial roof in ray fin fish
can be simple in one taxon, vexing in another. Here (Fig. 1) are a few taxa to illustrate what happens to the parietal in a phylogenetic series.
In particular
compare the knife fish, Gymnotus, with the stargazer, Uranoscopus (Fig. 1). The skull roof looks the same, but the parietals in Gymnotus are the supratemporals in Uranoscopus.
On the other hand, taking a more conservative route,
the lobefin fish, Eusthenoopteron (Fig. 1), retains the primitive skull roof pattern seen in Prohalecites, a basal bony fish, close to Hybodus and other sharks.
Thank you for your patience.
The Pterosaur Heresies 