Geoscience Reference
In-Depth Information
rocksofVictoria,Australia,oneofwhichwaseerilysimilartothefirstknowndino-
saur burrow, reported from Cretaceous rocks of Montana (USA) in 2007 (explained
more in the next chapter). In the non-dinosaur realm, the oldest tracks attributed
to four-legged animals from 395
mya
precede their body fossil record by about ten
million years. In short, trace fossils matter in paleontology, whether for supporting
new hypotheses or knocking down old ones.
So just what constitutes the evidence and scientific basis for a dramatic re-
write in the story of the Lark Quarry dinosaur tracksite? Also, how could this new
interpretation be wrong, exemplifying the fair warning that in science, just because
something is newer doesn't mean it's also better? The thought of an ornithopod im-
personatingalargetheropod—thedinosaurianequivalent ofitwearingclownshoes
(or, more aptly, “Bigfoot” shoes)—is not only a shocker for anyone who has grown
up hearing the tale of Lark Quarry, but it borders on heresy. In science, though, we
ratherenjoyslaughteringsacredcows,makingburgersoutofthem,addingacouple
of slices of bacon, and putting a fried egg on top. After all, hypotheses are only
accepted conditionally, and then are subject to further testing so we can find out
whether or not they still hold up to scrutiny.
Sometimes these hypotheses continue to stand (so far, so good) but more than
afewgetmodifiedorknockeddowncompletely.Andiftheygetknockeddown,it's
often because someone found data that better supports an alternative hypothesis, or
“another story.” Granted, “recycling” also happens sometimes, especially with sci-
entists who get a little too attached to a pet hypothesis, perhaps long after it's been
pronounced dead by everyone else (hey, egos happen). But for the most part, con-
sensus is based on the evidence—not the people, their degree of self-promotion, or
the volume of their message.
So just what was the evidence at Lark Quarry supporting the previous hypo-
thesis (which can be summarized as “big theropod maybe caused a panic because it
was preparing to kill and eat an ornithopod”), and how does this contrast with the
evidencesupportingthenewhypothesis(“bigornithopodmaybecausedapanic,but
