Defining Dinosauria

Richard Owen poses next to a Dinornis (moa) skeleton in 1879—but is it a dinosaur?

This group, which includes at least three well-established genera of Saurians, is characterized by a large sacrum composed of five anchylosed vertebrae of unusual construction, by the height and breadth and outward sculpturing of the neutral arch of the dorsal vertebrae, but the twofold articulation of the ribs to the vertebrae, viz. at the anterior part of the spine by a head and tubercle, and along the rest of the trunk by a tubercle attached to the transverse process only; by broad and sometimes complicated coracoids and long and slender clavicles, whereby Crocodilian characters of the vertebral organs also exhibit the same transitional or annectent characters in a greater or less degree. The bones of the extremities are of large proportional size, for Saurians; they are provided with large medullary cavities, and with well developed and unusual processes, and are terminated by metacarpal, metatarsal and phalangeal bones, which, with the exception of the ungual phalanges, more or less resemble those of the heavy pachydermal Mammals, and attest, with the hollow long-bones, the terrestrial habits of the species.

That’s how, in 1842, Richard Owen described “a distinct tribe or sub-order of Saurian Reptiles, for which I would propose the name of Dinosauria“, a group of organisms which needs no further introduction. But what, 170 years later, can be properly classified as a dinosaur? Former highschool science teacher Brian Thomas thinks he knows better than today’s scientists. He wrote on Wednesday, in “Four-Winged Dinosaur Definition Doesn’t Fly“:

URCall: Herodotus II: Dragons v. Ibises

From the ICR’s URCall series of videos, hosted by Markus Lloyd. “Are dragons really dinosaurs?” (link)

Transcript:

Have you ever heard of the tale of St. George and the dragon? Many cultures around the world have legends of dragons and winged serpents. The bible mentions them, and even historical figures like Marco Polo, Herodotus, and Alexander the Great wrote eyewitness accounts of them. Even today tales persist about the Loch Ness monster and the monster at Lake Champlain. Can these stories of dragons and sea monsters possibly tell of real accounts of human interactions with dinosaurs?

Are dragons dinosaurs? You’ll notice that the ICR doesn’t actually back this point up, they just point to accounts of dragons and make the leap to dinosaur. But the stories they allude to aren’t all that solid, especially when they have to now be of real dinosaurs.

Dinosaurs on the Ark

A new That’s a Fact video, Dinosaurs on Noah’s Ark, jumped today to the head of the short queue of episodes that I have yet to present to you. This is a topic we’ve seen many times before (e.g. two days ago), but it’s always fun:

Here’s your transcript and commentary:

Dinosaurs for Everyone

As you’ve probably heard, Ken Ham’s Creation Museum has recently acquired it’s very own Allosaurus skeleton. Ham boasts that it “is believed to have one of the four best-preserved Allosaurus skulls ever discovered.” He elaborates:

The new allosaur, as today’s news release states, “probably stood 10-feet high and 30-feet long. It stands out for a few reasons. It was found with its bones arranged in their correct anatomical positions relative to each other rather than in a scattered assortment of bones as is often the case. Also, much of the spine and 97% of the skull were found. Lastly, the skull is much larger than the famous ‘Big Al’ dinosaur at the Museum of the Rockies in Montana.”

Taking Job Literally

This That’s a Fact video was a long time coming, so I probably shouldn’t delay further in showing it to you. It’s called Dinosaurs and Humans, a title which says everything you need to know, really.

But Where is the Thagomizer?

The Khmer Empire-era Cambodian city of Mahendraparvata has recently been mapped with the aid of a technology known as “lidar” – effectively radar with lasers, hence the name. Today Brian Thomas has an article on the discovery called Jungle-Covered Ruins May Hold Surprising Hints. “Why?” you could reasonably ask, “and hints of what exactly?”

So far as I can tell, young Earth creationists care about the Khmer Empire for one reason and one reason only: the temple of Ta Prohm, located near the more famous Angkor Wat and constructed several hundred years after Mahendraparvata, contains on its walls a carving of what they claim is a stegosaurus, supposedly drawn from life. Mr Thomas says:

Breaking Eggs

A new That’s a Fact video has at last arrived. It’s called Jurassic Omelette – or, according to their website, “Jurassic Omemette.” They have at least fixed that now, though they’re yet to change the URL.

The subject matter should be broadly familiar. The video starts off with asking “which came first – the chicken or the egg?” before moving on to the dinosaur egg protein issue from the other week. Let’s not get ahead of ourselves, however.

Swimming with Dinosaurs

Dinosaurs left plenty of bones, but some also created another type of fossil: preserved track marks. A handful of these tracks were made from swimming dinosaurs, and a new paper in the Chinese Science Bulletin – A new Early Cretaceous dinosaur track assemblage and the first definite non-avian theropod swim trackway from China (open access) – reports on the discovery of one such find.

Timothy L. Clarey’s new article on these tracks is called Dinosaurs Swimming out of Necessity, but the “necessity” conclusion is entirely his own. His article is quite similar to one from Brian Thomas published in January which we looked at in Stampede? For instance both Thomas and Clarey chose to claim in their opening paragraphs that, in the present day, it is very difficult to form footprints that will eventually be preserved as fossils – here’s Clarey’s opener:

What’s so fascinating about dinosaur tracks? Maybe it’s because their many mysteries beg for solutions. For instance, because tracks in mud are so short-lived today, how did dinosaur tracks ever preserve in the first place? Newly described prints bolster biblical creation’s explanation of dinosaur footprints.

It may be true that it’s hard to preserve footprints in mud, but it’s not so improbable once you consider the shear number of footprints that would have been made over the more than 180 million years of the Mesozoic Era. Clarey never does explain, meanwhile, how “biblical creation” suddenly makes preservation so much easier – not even a “footprints need to be preserved rapidly” claim (which is false, by the way).

Stampede?

The several-thousand prints at the Lark Quarry dinosaur track-ways, in Queensland, Australia, have long been interpreted as being the result of the only known dinosaur stampede. They were caused, it was believed, by a large hungry theropod spooking and scattering a group of smaller dinosaurs. A new paper – Re-evaluation of the Lark Quarry dinosaur tracksite (late Albian–Cenomanian Winton Formation, central-western Queensland, Australia): no longer a stampede? (pdf, SI) – argues that the site does not represent a stampede at all, but dinosaurs swimming with the current as part of a migration. Somehow, Brian Thomas gets from this research the title “New Dinosaur Tracks Study Suggest Cataclysm.”

Nyasasaurus parringtoni

Nyasasaurus parringtoni, a dinosauriform from the middle Triassic, may or may not be the oldest dinosaur known to science. It was originally dug up in the 1930’s, but a proper description has taken until now to be published.

The description, in Biology Letters (open access well it was when I originally opened the tab – pdf here), is very conservative about claiming the “earliest dinosaur” title – they repeatedly insist that the fossil is merely “either the earliest known member of, or the sister–taxon to, Dinosauria.” This conservatism has apparently rather confused Mr Brian Thomas, as he alleges in his article World’s Oldest Dinosaur Fossil? that it’s all an evolutionary attempt to save face.