I’ve always assumed that Dinah and Dana were just early bloomers.
I too have always thought it odd that the LBT Triceratops in The Land Before Time hatch with their nose horns (the smallest horn) and grow their brow horns later. (Like Malte, I am also somewhat infatuated with jokes involving the number of Cera’s horns.
) But I think that Shinji-Lee is probably right that the lack of brow horns makes facial expressions easier to animate, and agree that Cera is much cuter and less intimidating with her nose horn alone. (Of course, tell her that, and the next thing you know, she’ll be holding up the animators at hornpoint demanding they give her her other horns so she can look scarier.
)
By the way, I did some research on those little frill projections; apparently, at least one ceratopsian paleontologist calls them epoccipitals (“ep-ock-sip-ih-tuls” is my best guess in terms of pronunciation). They’re structurally the same as the other horns on a ceratopsian’s head (extensions of the skull bones, probably covered in a keratinous sheath), so, as far as I know, Cera wouldn’t have been treading on any paleontological technicalities by referring to them as horns.
