Sitsqwayk is distinguished from other early chaeomysticetes by the features of the rostrum and skull roof, especially in the premaxillae. It differs from members of Eomysticetidae in that the dorsal edge of the skull ascends steeply towards the palate, and that the longitudinalkeel on the palate is sharp and narrow, constituting 75percent of the rostrum.
Phylogeny
Within Chaeomysticeti, Sitsqwayk is recovered as the most basal chaeomysticete, more primitive than eomysticetids and Horopeta.