Wednesday, October 23, 2013

Baby dinosaur!

Diagram and image of the skull of the baby Parasaurolophus, Joe.
Figure 7 from the published paper, showing
the skull of the baby dinosaur.

Reconstruction of an adult Parasaurolophus.
Image source.
I was not originally going to discuss this new find, as it does not directly have any impact on the creation/evolution debate, but news of it is spreading quickly, and other science news seems to be a bit slow today.

If you have not already seen the news reports, I will provide some background.  In 2009, high school student Kevin Terris stumbled across a bit of bone sticking out of the ground while prospecting for fossils with some other paleontologists at the Grand Staircase-Escalante National Monument in Utah.  The surrounding soil was removed to expose a nearly complete juvenile Parasaurolophus.  The paper detailing the find was published yesterday, hence the recent media coverage.  The specimen itself, which has apparently been dubbed "Joe," has its own website.

Juvenile dinosaurs are fairly rare, but this was the youngest Parasaurolophus found to date.  Parasaurolophus is characterized by the long bony crest that extends from its nostrils far out the back of the head.  The nasal passages fill the crest, and it is hypothesized that it could be used for unique vocalizations.  Part of the significance of this new find is the state of the crest.  In other crested hadrosaurs (duck-billed dinosaurs), the crest does not begin to form until later in life, whereas Joe already has a significant bump on his head.  This implies that the Parasaurolophus achieves such a long crest by starting its growth early.

As I said earlier, this does not have any direct impact on the debate, as the find relates more to ontogeny (development within an individual) than to evolution.  However, this does give a good opportunity to mention the reality of dinosaur bones.  Generally, most creationists have no problems with dinosaur bones in the ground, but some still seem to reject the idea that these extinct creatures once roamed the earth.  Some people claim that paleontologists just make up the bones, carving them from rocks; others say that Satan created dinosaurs and that God wiped them out to create his own animals; and still others say that God just put the bones in the ground "to test our faith."  I don't understand the reasoning behind any of these ideas, if there is any.  I can attest that paleontologists do not simply manufacture the bones.  I myself have found numerous dinosaur bones in Wyoming and South Dakota.  Biblically speaking, there is nothing that excludes these creatures as creations of God that once walked this planet and are now extinct.

According to the creationist view, dinosaurs were created on Day 6 of creation week along with all other land animals approximately 6000 years ago.  They persisted contemporaneously (not necessarily cohabiting) with humans, at least until Noah's Flood, approximately 4400 years ago.  This worldwide event, creationists say, is what deposited a majority of the rock layers and fossils found on the earth.  Two of each kind (note: not "species") of dinosaur survived on the Ark, along with all other air-breathing land animals to have a chance at repopulating the land.  Over time, the dinosaurs gradually died out, due to several possible factors such as less plentiful vegetation, colder temperatures, hunting, and generally being outcompeted by mammals in the post-Flood world.  It is thought that dragon legends originated from ancient interactions with dinosaurs before they went completely extinct.

I assume that I do not need to detail the evolutionary view, as it is quite well known, but I will give a brief outline.  It is said that dinosaurs evolved from archosaurian reptiles in the Triassic Period, approximately 230 million years ago.  They quickly became the dominant land-dwelling animals and diversified for the next 165 million years or so.  At the end of the Cretaceous, approximately 66 million years ago, an asteroid impact drastically changed the climate, leading to the extinction of all dinosaurs except those that evolved into birds.  Birds are quite literally considered dinosaurs by the modern paleontologist, so it is common to add some sort of modifying phrase when claiming that dinosaurs are extinct (i.e., "all nonavian dinosaur groups went extinct at the end of the Cretaceous period").

Dinosaurs are amazing creatures, regardless of your views on their history.  They are often the first subject to come up in a discussion of biologic history, and they can spur many people, including me, to investigate the origins issue further.  Interpretations of their bones vary by worldview, by educational background, by experience, and almost by the individual.  Aside from the dates attributed to the remains, I think the authors did a great job in presenting the bare, quantitative facts in their report.  Let's go find some more dinosaurs!

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