As Kacie and Stitch said, the new hypothesis regarding
Triceratops (proposed by Horner and Scanella) is that
Torosaurus is actually an old
Triceratops. It is known that the skull of
Triceratops changed dramatically as it aged: yearlings had tiny, straight horns and a short, solid, backward-facing frill rimmed with small spikes (epiparietals); adolescents had larger, upward-curving frills (still spiked) and longer, backward-curving horns, and adults had forward-pointing horns, broad frills, and shorter, rounder frill adornments.
The new idea is that older
Triceratops changed further, developing longer, squarish frills with large holes in them to reduce weight: these individuals are represented by the related ceratopsian known as
Torosaurus, which was virtually identical in size and appearance to
Triceratops, apart from the aforementioned frill and some other features of the skull. Horner and Scanella's reasoning is that
Torosaurus remains are only known from the same localities as
Triceratops,
Torosaurus is much rarer, there are no known fossils of young
Torosaurus, and adult
Triceratops skulls show evidence of being ton their way to developing
Torosaurus characteristics such as the frill spikes disappearing (Maybe your source had some of the details wrong, but these were probably the “horns” you were referring to, Iris).
This is a radical idea, so, not surprisingly, there have been many arguments against it.
This post (whose author, I believe, is an “armchair paleontologist” like myself, but a more educated one) is a good example, and covers the subject quite thoroughly, though you have to have a certain understanding of paleontology in order to comprehend it easily. Some of the counter-arguments it presents are that
Torosaurus's preferred habitat was not well suited for fossilization, so the only
Torosaurus that were preserved were the few that wandered into
Triceratops habitat; the reason for the apparent lack of juvenile
Torosaurus fossils is simply that we haven't found any yet; and that, if so few
Triceratops reached the stage of their lives in which they developed
Torosaurus characteristics, why did they have that stage at all? Plus, just because two dinosaurs were similar, lived in the same place at the same time, and COULD have changed in such a way over their lives that one essentially grew up into the other, doesn't necessarily mean that they are the same species. I'm rather skeptical about it myself, but personally I think there's not enough evidence to either prove or disprove the hypothesis.
Even if
Triceratops and
Torosaurus do turn out to be the same dinosaur, threhorn fans need not despair.
Triceratops was named two years before
Torosaurus, so if the two genera were synonymized, the name
Triceratops would take precedent, and
Torosaurus would go the way of
Brontosaurus. And most
Triceratops would still look like
Triceratops; if Horner and Scanella's hypothesis proves correct, it's only the oldest
Triceratops that would look any different, and even for them the change would mostly entail just a longer, more rectangular frill with faintly visible “windows” covered by skin. (Also, there were two species of
Triceratops:
T. horridus and
T. prorsus; for all we know, perhaps only one received a
Torosaurus face-lift in its senior years.)
Furthermore, while this may not necessarily induce cheeriness in LBT fans, it would hardly matter to the series' scientific credibility if
Torosaurus (which hasn't even appeared in LBT) ends up being sunk into Cera's species. Frankly, if this constitutes a scientific fail for LBT, then it's only the latest of many (several of which are excusable due to the fact that LBT was produced long before they were made). If you were to remake LBT accurately, Ducky's species wouldn't be any more of a swimmer than any other dinosaur, and her parents would probably spend most of their time on four legs; Petrie would eat fish (or at least not plants), be unable to grasp with his feet, and would also be primarily a quadruped; all of the main dinosaurs would be different in the number of claws and toes they had on their feet (Ducky's hands would resemble thumbless mittens with an opposable pinky); Spike would have a much narrower body and a longer neck with an armored throat; and Cera would have three horns, just to name a few. (Oh, heck; I should have just directed you all to the “Realistic Gang” picture I made for pokeplayer984's video.
)
So, to recap,
Triceratops STILL exists, and even if it didn't look exactly as most of us imagine it did when it reached nursing home age, it won't make an earth-shatteringly huge difference in our perception of it. Its greatest ramification for LBT is that Cera will get to look forward to having an even more intimidating frill when she gets older. Anyway, I hope that clears things up.
