Why Are All the Big Dinosaurs Found in South America?

Slate has an interesting piece on som erecent dinosaur finds in Argentina:

Paleontologists announced on Monday that they had discovered the remains of a 105-foot-long dinosaur on the banks of a lake in the Argentine portion of Patagonia. The Futalognkosaurus dukei ranks among the largest known dinosaurs, along with two other species whose remains were discovered in Patagonia, the Argentinosaurus and Puertasaurus reuili. Why are all the biggest dinosaurs found in Patagonia?

They died at the right time in the right place. Patagonia happens to be an excellent place to find fossils from the Cretaceous Period, when dinosaurs reached their largest sizes. (The extinction of the dinosaurs occurred at the end of the Cretaceous, about 65 million years ago.) Because of natural uplift and erosion, sediment that dates from this time is exposed at the surface in the region's desert badlands. This makes fossilized bones easier to spot and excavate. (Fossils are also easy to find in the badlands of the Dakotas, Wyoming, and Montana, as well as in Mongolia's Gobi Desert.)

Interesting stuff, and a useful reminder of the fickleness of the fossil record. I'm always a bit amazed when creationists point to gaps in the fossil record as some sort of indictment of evolution. Considering all the lucky breaks you need for any ancient critter to not only be fossilized in the first place, but then wind up in a place where it can be found by scientists, it's incredible we have any fossils at all!

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"They died at the right time in the right place. Patagonia happens to be an excellent place to find fossils from the Cretaceous Period, when dinosaurs reached their largest sizes."

This statement is not true elsewhere, at least for plant eaters. The largest plant eating Cretaceous dinosaur in North America was the 12 ton Triceratops. A mere pygmy when compared to a 55 ton Jurassic brachiosaurus.

I think it would be an interesting thing to make a list of animals NOT in the fossil record and the reasons why not, compared with a list of those represented. For example (and I'm just making this up) there are no mountain goats because they live in areas where fossilization is too remote a possibility, but clams are over-represented due to their location in shallow waters.

How many extant species are represented? I remember reading that the only fossilized chimpanzee ever found was only found recently and was only a jaw bone. It was a bit of a shock and it made me think of the "if there were transitional species we should find them all" argument. If we don't have any fossil proof of animals we see right now, shouldn't that be an indicator that the fossil record isn't anywhere near as complete as we'd like it to be?

shouldn't that be an indicator that the fossil record isn't anywhere near as complete as we'd like it to be?

Well, it would be difficult for the record to be as complete as we'd like - ideally we would have a representative sample of every generation of every organism, but that's not only unlikely given the mechanisms of fossiliation but probably physically impossible.

Not having an extensive fossil presence of creatures we coexist with strengthens the idea of transitional species, not weakens it. If we had lots of fossils of modern creatures, then the presence of gaps would be more problematic. It's because the record is incomplete that complaints about gaps are unreasonable.

By Caledonian (not verified) on 18 Oct 2007 #permalink

Caledonian-
I think that you misread pough. I think that you are in agreement.

I think an interesting fact the original article doesn't state, but is critical to considering the completeness of the fossil record (especally of SouthAmer mega Dinosaurs) is that ALL large sauropod dinosaurs above 30m are known from VERY incomplete specimens.

Argentinosaurus was only known from a (very large) vertabrae as of my last extensive dealings with dinosaurs a year ago. We can only postulate at its true size from these remains. It supports a size of over 30m through comparison to the FEW complete sauropods we have.

Also supporting this size estimate IS the lack of complete preservation. How next to impossible would it be to completely bury a corpse of an animal this size? The bones are HUGE (granted I am surprised more ribs and digit elements aren't found in bonebeds) burying a femur of such a beast would require more than a meter of sediment just to cover it when lying before decomposition and scavaging could destroy it! how many flooding systems in the world deposit at this rate? that alone single flooding events? than of course with such an unstable and violotile water system in play what 60 ton+ animal could live there and not fall over all the time?

This is adds more weight to the arguement of fossilization being a lucky thing.

Though I don't like this wording of "lucky" as it opens holes for creationists. "If it's luck than obviously evolution is a lucky outcome thus far of this geologic lottery, and years from now you're luck will run out due to (insert something about god's intervention here)"

I'm sure everyone here agrees fossiliazation is predicatable process, but one that is based on probability of a huge array of completely random elements (animals size, enviroment animals dies in, water volume, water speed, sediment capacity, etc).

I just wish someone would coin a phrase that would catch on in the mainstream that caused a association with orderly inputs, but totally random outcome. Thus getting rid of the "luck" from fossilization.

I would like to point out that the geologic column has meany promblems for instance; the geologic column found in the textbooks and other scientific publications is not what you would find in the real world. 95% of all fossils are clams and similar organisms. There are fossilized clams in every region pf the world in almost all layers of rock. The geologic column is really only about 5% of the fossil record. so when we talk about the geologic column we are only talking about a very small part of the fossil record. Talking about clams did you know there are fossilized clams in the closed position on top of Mt. Everest. How did they get there. Did they walk. No. Did they fly. No. Clams niether can walk or fly. I believe that during the flood the clams were washed on Mt. Everest. Is there evidence to support this. Yes, you see clams in the closed position have to be buried very quickly otherwise they open up. (Because when the clam dies the mussel relaxes.)
Also according to evolution it takes millions of years to form fossils. Is this possible. Alright what you need for this experiment is;
One dead animal
Now take it to the backyard and leave it thier. Observe for a month. Will it fossilize. No. What will happen is it will be eaten, rot, and decay. Fossils can not be made this way. Fossils have to be buried very rapidly in order to fossilize. When I look at all the fossils in the world I can only explain it as come from a world wide flood. There are aslo fossil grave yards that have fossils jammed together in odd positions and angles some of the fossils have limbs torn off. There are sometimes thousands of different organisms including dinosaurs and other mammels. It looks like it was a big eddy which sucked in the different organisms. This is more evidence for a global flood.

Ben-
Its very frustrating when mountains of literature have been
written by legions of very thoughtful, accomplished professional scientists which carefully answer your concerns; but you choose to not to bother with their hard work. Fine, many people dontno problemyou have your interests & we have ours. However, you cant then try to present an opinion about scientific inquiry & expect to be
taken seriously & not come off as buffoonish. I suspect that Im wasting my time, however Ill make an attempt to try to get through to you. Im not going to address all of your points because youve already demonstrated an unwillingness to do the work involved in the learning process. However, just as a starting point for you (just in case), & Ill try to make it as simple for you as possible:

fossilization + plate tectonics = clam fossils (open, closed, or any way you like) on the top of Everest.

Oh hell, here's another one for you: Where did all that water go that covered the entire Earth surface to an elevation of the top of Everest. If you invoke God then you can't really use a natural explanation in other places.

Ben: "Talking about clams did you know there are fossilized clams in the closed position on top of Mt. Everest. How did they get there."

The fact that you have asked this question on a Web Blog means that the answer to your question was literally at your finger tips. Just type "Himalayas Geology" into Google and you will get some useful clues to your puzzle.

The Himalayas were formed when two landmasses collided approximately 70 million years ago, before then the area that is now the Himalayas was the Tethys sea. When the landmasses (or plates) collided the sea bed was folded into longitudinal ridges and valleys and was elevated into high mountain ranges. The clams did not need to 'walk', 'fly' or be 'washed' up Mt. Everest as the rock of the Himalayas was once a seabed.

Traumador said "just wish someone would coin a phrase that would catch on in the mainstream that caused a association with orderly inputs, but totally random outcome. Thus getting rid of the "luck" from fossilization."

I believe S. J. Gould already had come up with the term "contingency" (as in a random event), which I like.

I guess suggesting that plate tectonics carried the clams to the top of everest is an easy explanation. Why don't you explain how 10 meter whale skeletons are being discovered at elevations 5,000 feet above sea level without a single vertabrae out of place? Let me guess, they just surfed the mountains for 70 million years until they reached their final destination without disturbing a single bone! Come on, seriously!

Where did all the water go? Have you ever been to the ocean? Read Psalms 104: 6-8...

"The waters were standing above the mountains. At your rebuke they fled, at the sound of your thunder they hurried away. The mountains rose, the valleys sank down."

Before the flood of Noah, we did not have the great mountain ranges that we have on earth today. Mt. Everest was not as high back then, just as the scripture says, "the mountains rose." They rose due to crashing plates and the immense weight of the water.

Jacque Cousteau, the great ocean explorer explains it very simple:

"Were the crust of the earth to be leveled with great mountain ranges like the Himalayas and ocean abysses like the Mariana Trench evened out, no land at all would show above the surface of the sea. Earth would be covered by a uniform sheet of water more than 10,000 feet deep."

Where is all the water? Simple. It is in the ocean.

Could the sauropod dinosaurs from South America be so gigantic not just because of a natural evolutionary process,but also the fact that South America was their last stronghold, without any competition? After all, they went into decline everywhere else in the world, but in South America they retained their position as the dominant land herbivores, just like in the Jurassic. A point to ponder, I think.

By Raymond Minton (not verified) on 29 Jan 2009 #permalink

Jim,

You asked, "Where did all that water go that covered the entire Earth surface...?" I almost forget to ask the obvious! Why do you think it is ludicrious to postulate that the remaining 29% of the earth's surface could be covered in water?

71% of the earth is already covered in water, but you can't reason the remaining 29% was once covered? Instead, the "brains" of modern "science" are claiming mars was covered in water. Obviously, Mars is dry as a bone!

It's your sin not your science that keeps you from God.