Monday, January 21, 2013

A thought on "living dinosaurs"

No one can resist dinosaurs. Even more than dragons (see post from a few days ago), dinosaurs hold our imagination because they were the real dragons - and European and Chinese chroniclers of dragonlore never invented anything more impressive. 
Dinosaurs, it is almost universally thought, disappeared 60M years ago following the so-called K-T impact, when the world changed, the dust clouds and cold descended, the dinosaurs died off (not instantly, but pretty quickly in geological terms) and the way was cleared for the ascendancy of mammals and birds.  Occasional claims of post K-T dinosaur fossils are written off as mislabeled or reworked from older deposits as land folds, rises, or recedes under the pressures of millions of years' worth of geological processes.
Dr. Karl Shuker, always worth reading on this subject, offered a Top Ten claims of surviving dinosaurs. Some are easy to dismiss: there's no evidence motorists in Chile in 2004 saw velociraptors, or that a "stegosaur" bas-relief carved in Cambodia shows anything except a boring old tapir in front of a bush.  Stories from South America and Australia are, in general, sourced from one person, or someone claiming to quote indigenous people who are now long dead.  Trying to overturn the dinos-are-dead paradigm with this material is like charging an elephant armed with a broom handle. 
The one that pops up as relatively well-sourced is mokele-mbembe, known by several other names as well and described from various places in the Congo River basin in Africa.  I say "relatively" because there are some 20th-century sighting reports, and there are some photographs and videos, taken (either unfortunately or expectedly, depending on your point of view) from too far away to show anything useful. Dr. Roy Mackal, who went on an arduous expedition but didn't see the creature, thought it could be a small sauropod or possibly a huge monitor lizard.  He wrote an undeniably intriguing book on the subject. 
And yet - many expeditions later, we don't have a good sighting by an outside scientist, a good image, any remains of an animal.  Paleontologist Louis Jacobs, in the only book on African dinosaurs, ridiculed it, arguing this area is not a "lost world" unchanged since the Mesozoic. 
My take? We're not going to find a dinosaur. Not in Africa, not anywhere.  I think we are going to find more large land animals, but if we've already seen the best evidence, we haven't seen enough to support anything as science-shattering as living dinosaurs.
Unfortunately. 

7 comments:

Clark said...

How is a stegosaur really any different than a giant armadillo if you reconstruct it less imaginatively and with the plates laying flat?

Matt Bille said...

Interesting thought.

Clark said...

When defining a species is recognized to be very arbitrary what sense is there in saying the iguanodon is not a giant iguana?

Many giant armadillos are known in the fossil record, some the size of a car.

If these two ideas are reasonable then it reduces the strangeness of the dinosaurs and the supposed divide at the End Cretaceous. This would make the change more of a continuum.

Clark said...

It is often recognized by professional paleontologists that the supposed mass extinctions are an artifact of the method Lyell used to define the eras based on the number of taxa surviving from that strata.

Clark said...

The okapi is a lazarus taxa or prehistoric survivor yet George Gaylord Simpson preferred to consider that it was not one. The reason was it was not known in the fossil record. All of the short-necked giraffes in the fossil record were different from it. He said it was not a Samotherium. This should not blind one to the fact that a short-necked giraffe is a lazarus taxa in some significant sense.

Clark said...

In his article, "Mammals and Cryptozoology", Simpson called the okapi a "supposed survivor of an otherwise extinct group." Considering you had the okapi on the cover of your book, what would you say to that? He says it is not a Helladotherium, a Miocene giraffid. He says, "In some respects Okapia is somewhat more like early giraffids such as Paleotragus Gaudry,1861, (late Miocene to early Pliocene), but it has become distinctly different." And he says, " Okapia is not a survivor of a known fossil genus, subfamily, or family." The general sense of what he says is to suggest its discovery has little significance, even though he admits it was long known to natives as he insists most people did not doubt its existence. Why does he play down this discovery and what is the deeper significance of it? Considering that short necked fossil giraffids were known, to claim it is not a prehistoric survivor seems to miss the forest for the trees.

Matt Bille said...

Clark, thanks for all the comments. The mass extinction item is debated, but you still find most paleontologists using the term. The extinctions just were not as instantaneous as we used to think.