Fix the error. Ray fins, of course. The actinopterygians form an outgroup in these cladograms, that show uncertainty about which extant sarcopterygian is most closely related to the tetrapods. There are many such uncertainties, perhaps in part because even major evolutionary changes seem to occur so quickly they are hard to resolve.
Time is a crucially important factor in attempting to understand patterns of vertebrate evolution.
The conclusion from the SINE element study, that whales derive from ruminants, a subgroup within the artiodactyls, presents something of a paradox when we add into the equation the element of time . However, the most primitive artiodactyls, as deduced from the fossil record, appear only in the early Eocene, at the same time, or even later than whales. Well, descendants can t arise earlier than their ancestors, clearly. We can easily propose that something basic in our understanding of early whale evolution is wrong. I expect this proposal would cause some grief to the specialists in this field who make their livings from character analysis of fossil ungulates.