Two great joys of my spring so far: Watching the world green up and the birds get frisky as I sit on my back porch, and visiting the Smithsonian’s National Museum of Natural History, where I got to go behind the scenes and see the vast and astonishing collection of dinosaur bones.
These are overlapping events in the sense that birds are dinosaurs. Birds are not merely descended from dinosaurs; they are dinosaurs. Those six chickens clucking in my neighbor’s yard? Dinosaurs. Or so I’m told. I confess I struggle with the birds-are-dinos concept, as I do with the idea that, back in the day, Tyrannosaurus Rex may have had feathers.
We wrote the other day about a new T. rex discovery, a great one, because it’s from a huge gap in the fossil record in the Cretaceous. The new dinosaur, Timurlengia euotica, was discovered in Uzbekistan in a sedimentary formation dated to about 90 million years ago. There are almost no rocks on Earth from that era that preserve terrestrial fossils. The gap in the Cretaceous fossil record runs from about 100 million years ago to 80 million years ago. Before that, you see small tyrannosaurs, human-sized or a little larger. But after the gap, as we get late into the Cretaceous, to the period just before the K/T extinction, we see these giant tyrannosaurs, like T. rex, up to 40 feet in length, smart and highly adapted to see, smell and hear their prey, and with giant heads and humongous teeth and the ability to bite through bone and eat a hapless duck-billed dinosaur pretty much whole.
Timurlengia is striking for having the advanced sensory apparatus of the later T. rex, but not the size. This new dinosaur was only about horse-sized (the size is hard to estimate because they have only a smattering of bones). The discovery suggests that tyrannosaurs got smart, with keen senses, before they got big.
So basically, we’re seeing dinosaur evolution in action, one hard-to-find fossil at a time.
When I posted the story, a reader objected to my use of the phrase “missing link.” Argument was: This will only encourage the evolution-deniers.
It’s true that “missing link” carries some baggage, because people who reject evolution claim there’s not enough evidence in the fossil record to prove that humans evolved from earlier primates. But I thought “missing link” was the perfect phrase for this particular discovery. Also, someone who rejects evolution will not be persuaded or dissuaded by anything I write, as this is the classic tribal belief system. I assume my readers are intelligent and educated and I generally don’t frame stories defensively, or get tied in a knot because someone out there will misappropriate a phrase for a pseudo-scientific purpose.
Rejecting evolution is like rejecting mathematics. You never hear about activists demanding that a separate theory of addition and subtraction and multiplication and division be taught in schools alongside arithmetic.
Life, to the extent that we can definite it at all, requires evolution. Evolution isn’t superimposed upon life; it’s the foundation of everything. And sitting on my back porch I can tell you that it has put on quite a show. One wants to clap in appreciation. Admittedly, I think there are too many robins (what I call “the bad dinosaurs”). I also don’t like the birds that eat my grass seed, but I guess that’s just “Nature, red in tooth and claw” (inner suburb edition). If I were in charge, I might rearrange things a bit in terms of the diversity of species, and make orange trees grow in the mid-Atlantic, and get rid of the mosquitoes and the rats. But this nature thing is pretty great as it is, you have to admit.