Last dinosaur before mass extinction discovered

Jul 13, 2011
Three small primitive mammals walk over a Triceratops skeleton, one of the last dinosaurs to exist before the mass extinction that gave way to the age of mammals. Credit: Mark Hallett

A team of scientists has discovered the youngest dinosaur preserved in the fossil record before the catastrophic meteor impact 65 million years ago. The finding indicates that dinosaurs did not go extinct prior to the impact and provides further evidence as to whether the impact was in fact the cause of their extinction.

Researchers from Yale University discovered the fossilized horn of a ceratopsian – likely a Triceratops, which are common to the area – in the Hell Creek formation in Montana last year. They found the fossil buried just five inches below the K-T boundary, the geological layer that marks the transition from the Cretaceous period to the Tertiary period at the time of the that took place 65 million years ago.

Since the impact hypothesis for the demise of the dinosaurs was first proposed more than 30 years ago, many scientists have come to believe the meteor caused the mass and wiped out the dinosaurs, but a sticking point has been an apparent lack of fossils buried within the 10 feet of rock below the K-T boundary. The seeming anomaly has come to be known as the "three-meter gap." Until now, this gap has caused some paleontologists to question whether the non-avian dinosaurs of the era – which included Tyrannosaurus rex, Triceratops, Torosaurus and the duckbilled dinosaurs – gradually went extinct sometime before the meteor struck. (Avian dinosaurs survived the impact, and eventually gave rise to modern-day birds.)

Yale graduate student Stephen Chester discovered the last known dinosaur before the catastrophic meteor impact 65 million years ago. Credit: Tim Webster

"This discovery suggests the three-meter gap doesn't exist," said Yale graduate student Tyler Lyson, director of the Marmarth Research Foundation and lead author of the study, published online July 12 in the journal Biology Letters. "The fact that this specimen was so close to the boundary indicates that at least some dinosaurs were doing fine right up until the impact."

While the team can't determine the exact age of the dinosaur, Lyson said it likely lived tens of thousands to just a few thousand years before the impact. "This discovery provides some evidence that didn't slowly die out before the meteor struck," he said.

Eric Sargis, curator of vertebrate paleontology at the Yale Peabody Museum of Natural History, and graduate student Stephen Chester discovered the ceratopsian last year while searching for fossilized mammals that evolved after the . At first, Lyson said, the team thought it was buried within about three feet of the K-T boundary, but were surprised to learn just how close to the boundary – and hence, how close in time to the impact – it was. They sent soil samples to a laboratory to determine the exact location of the boundary, which is marked by the relative abundance of certain types of fossilized pollen and other geological indicators but is difficult to determine visually while in the field.

Because the dinosaur was buried in a mudstone floodplain, the team knew it hadn't been re-deposited from older sediments, which can sometimes happen when fossils are found in riverbeds that may have eroded and re-distributed material over time.

The team is now examining other fossil specimens that appear to be buried close to the K-T boundary and expect to find more, Lyson said. He suspects that other fossils discovered in the past may have been closer to the boundary than originally thought and that the so-called three-meter gap never existed.

"We should be able to verify that using the more sophisticated soil analysis technique rather than estimating the boundary's location based solely on a visual examination of the rock formations while in the field, which is what has typically been done in the past," Lyson said.

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kevinrtrs
1.3 / 5 (31) Jul 13, 2011
A team of scientists has discovered the youngest dinosaur preserved in the fossil record before the catastrophic meteor impact 65 million years ago. The finding indicates that dinosaurs did not go extinct prior to the impact and provides further evidence as to whether the impact was in fact the cause of their extinction

This is a really strange sentence. First it says with all authority that the dinos died because of a meteor impact, then it turns around and casts huge doubt on whether they actually did die in such a disaster.

Since the meteor impact is simply sheer speculation, it's very possible that there were other causes for the mass extinction of the dinosaurs. One global flood as described in the bible and a subsequent ice age comes to mind as far better explanations for dinosaur extinction.
It would be very interesting to know what other fossils are discovered in the K-T boundary. Might be that there are fossils of birds and foxes mixed in. Would they report them?
roboferret
4.8 / 5 (23) Jul 13, 2011
Kevin: The cause of the extinction is still being investigated and debated. The meteor impact itself is not speculation. In fact, there are several confirmed meteor craters large enough to have caused mass extinctions, how do these fit into your YEC chronology? Pre-flood? Post-Flood? Did Noah's Ark surf on the multi-km high waves? I was brought up as YEC, but I actually bothered to check if the creationist claims held any water. Turns out they don't, and the bible frankly doesn't hold much merit as a historical document, let alone the word of God.
SincerelyTwo
not rated yet Jul 13, 2011
Why am I not allowed to delete my own messages?
Yellowdart
1.6 / 5 (16) Jul 13, 2011
The meteor impact itself is not speculation.


The problem with either disease or meteor impacts is that they don't cause fossils.

how do these fit into your YEC chronology? Pre-flood? Post-Flood?


Probably during or shortly after. Most of your rock being expelled during the initial few weeks, plastered Mars, the moon, and ended up as your asteroid belt. Asteroids are largely made up of water/ice and some rock. So the debris that didn't quite make it out of orbit, would have fallen back to earth.
d_robison
5 / 5 (11) Jul 13, 2011
The meteor impact itself is not speculation.


The problem with either disease or meteor impacts is that they don't cause fossils.

how do these fit into your YEC chronology? Pre-flood? Post-Flood?


Probably during or shortly after. Most of your rock being expelled during the initial few weeks, plastered Mars, the moon, and ended up as your asteroid belt. Asteroids are largely made up of water/ice and some rock. So the debris that didn't quite make it out of orbit, would have fallen back to earth.


1) No one stated that meteors or disease cause fossilization, there are several types of fossilization and none of them are dependent on how an organism dies.

I don't know how to respond to the second part as its mostly gibberish.
thales
5 / 5 (4) Jul 13, 2011
Most of your rock being expelled during the initial few weeks, plastered Mars, the moon, and ended up as your asteroid belt.


It's not your rock, your asteroid belt? Sounds like you don't quite identify with being human...

Or maybe it's just from being so isolated. Like so: http://www.penny-...04/4/30/
Waterdog
5 / 5 (10) Jul 13, 2011
Don't encourage the YECs with responses. And heaven forbid that you confuse them with the facts.
ROBTHEGOB
2.3 / 5 (3) Jul 13, 2011
I must have missed something: what is YEC?
Shelgeyr
4.2 / 5 (5) Jul 13, 2011
A team of scientists has discovered the youngest dinosaur preserved in the fossil record before the catastrophic meteor impact 65 million years ago.


His name was "Steve". He liked sunny rocks, and small fur-bearing morsels. He lived fast, played hard, and left us way too early. (sniff) Why do the good always die young?

At least he managed to reproduce first, and was an ancestor of Wolfgang Mozart (See Also: Vitamin D thread).

I would think I had spotted a trend with these oddball "died young" articles, except that "two" does not a trend make. If a third crops up soon though, I'll start to worry...
mrlewish
5 / 5 (4) Jul 16, 2011
YEC = Young Earth Creationism

pronounced sort of like Yuck for obvious reasons.
Yellowdart
2 / 5 (4) Jul 18, 2011
No one stated that meteors or disease cause fossilization, there are several types of fossilization and none of them are dependent on how an organism dies.


It is entirely dependent. Erosion, explosions, and predators are not friendly to fossilization. Your best opportunity is a body buried in sediment and water so that premineralization occurs.

Of course there are other means like lava flows, and amber, freezing, compression. None of which will do a good job of telling you two bits and tiddles about a meteor or disease, and how other species were affected outside of that location. They only tell you how that organism, died.

I don't know how to respond to the second part as its mostly gibberish.


The gentlemen was asking, how the Flood explains meteor impacts. What's so hard to understand? If you shoot an object into space, and it does not escape orbit, where does it go? It falls back to earth.
NotAsleep
not rated yet Jul 18, 2011
I hope that the article oversimplifies the thinking of the archaeologists doing the work. It would be unfortunate to throw out years of observations about the 3-meter gap with a single finding inside that gap