|And he means business -- just check out that switchblade comb.|
[by the author]
Ah, Brontosaurus. The name all of us in the palaeo community were too good to admit we never stopped using, when it was just us, alone where nobody would overhear, with our sketchpads and our toys and our old-timey books.... Brontosaurus. THE Thunder Lizard. THE dinosaur, quite probably. Brian Switek didn't write a book called My Beloved Apatosaurus, now did he? No, no, no, when we walked around museums with our families or read a children's book aloud, it was always strict business, 'Well, ACTUALLY, Brontosaurus is a junior synonym of Apatosaurus, which was named and described earlier, so that's the CORRECT name,' that line of talk. But not in our heads, and certainly not in our hearts. Brontosaurus, baby, it's great to have you back... but you never really left us. Not really.
Of course, that's just thing. Brontosaurus never went anywhere - not culturally, of course, but not scientifically either. The animal Brontosaurus excelsus was always its own unique taxonomic entity. Had Elmer Riggs, back in 1903, argued that Brontosaurus excelsus was not different enough to warrant species-level separation from Apatosaurus ajax, well, that might have been something else, but it was always clear that B. excelsus was its own unique species. Riggs argued instead that Brontosaurus excelsus wasn't different enough to warrant genus-level separation from Apatosaurus, even though it was clearly not the same as any species of Apatosaurus. The thing about arguing synonymy for taxonomic ranks, though, is that there aren't actually rules for how inclusive or exclusive things like species - or even worse, genera - have to be. When you're working on fossil animals, without the benefit of life appearances and breeding patterns, nailing down a species is tricky enough. Genera, even in the world of modern zoology, are pretty much totally arbitrary.
The Rules of the (Name) Game
The number of differences used (13 or more differences to are needed to separate species into genera) in the revision of Diplodocidae was selected to keep useful concepts of Apatosaurus and Diplodocus alive. This may seem to be arbitrary -- and to a point, it is -- but it reflects the goal of modern taxonomy, which is to classify organisms based on their evolutionary relationships to one another, and to allow scientists to discuss and study these organisms. Splitting these genera too thin, or alternatively, lumping even more wildly than the most ardent of Greg Paul fanboys would make any discussion of the evolutionary and morphological diversity of Diplodocidae too complicated to be useful. It just so happened that in the process of evaluating the diplodocids along these lines, which do reflect genuine evolutionary relationships, a group of animals long considered by scientists to be Apatosaurus fell outside the boundaries of Apatosaurus under this paper's definition. These animals formed a natural group, meaning they shared an evolutionary history with each other to the exclusion of other animals, and as such needed a name. The oldest, and thus scientifically rightful, valid name that was available happened to be Brontosaurus.
And lo, Brontosaurus riseth again, through that age-old miracle of low-level taxonomic reshuffling.
|Two Brontosaurus excelsus prepare to slam down in the form of ancient combat|
known only as BRONTOSMASH! This depiction is based on recent studies that
suggest apatosaurine necks were specially adapted for combat, and may have
supported keratinous knobs or spikes along their lower edges. Read more
over at SV-POW! -- where this very drawing was featured!
[by the author]