Microraptor

For Wednesday’s DpSU we have Is New Fossil a Bird-Eating Dinosaur? Brian Thomas has a wonderful habit of randomly disagreeing with palaeontologists about the classification of various bird-like dinosaurs. If you believe him, you’ll think that Caudipteryx has no feathers, that Balaur is not bird-like at all, and now that Microraptor is a true bird (and also, not a dinosaur).

The holotype of Microraptor gui

The actual study is about a fossil of Microraptor gui – the picture above is or a different fossil of the same species – that contains a bird (an actual bird) inside its stomach. The paper argues that the fact that Microraptor has eaten – and apparently not scavenged – an arboreal bird, it must have lived in the trees and was probably able to glide (but not fly). The implications of the study are discussed in this WEIT post, and you can see some of the figures in the paper there as well.

To begin at the beginning of Brian’s article:

A new fossil was uncovered in China with bird bones in its ribcage—right where its stomach must have been. Researchers consider it to be a predatory dinosaur that ate an adult bird just before it died. But was it really a dinosaur?

Microraptor is classified as a Dromaeosauroid, which are considered to be the group of theropod dinosaurs most closely related to birds. The super family includes Velociraptor and Balaur. It is therefore a dinosaur, like all birds, but it is not a bird itself.

This was such a rare find because the creature apparently did not have enough time to digest its food before it was killed and subsequently fossilized. The still-connected bones of the eaten bird’s feet enabled paleontologists to positively identify it. The creature that ate the bird, however, proved more difficult to classify.

I am, unfortunately, unable to read past the abstract of this PNAS paper. From it, however, I get the impression that they were unable to identify the bird to any specificity beyond that it is an enantiornithine, which is probably where the feet bit comes into it, and make further inferences based on the known enantiornithines of the place and time. I don’t get the impression from the abstract – or from Coyne’s WEIT post – that there was any doubt over whether or not the carnivore was a Microraptor. To quote the second sentence of the paper:

Here, we report on a unique specimen of the small nonavian theropod Microraptor gui from the Early Cretaceous Jehol biota, China, which has the remains of an adult enantiornithine bird preserved in its abdomen, most likely not scavenged, but captured and consumed by the dinosaur.

To continue with the DpSU:

In a report published in the Proceedings of the National Academy of Sciences, three investigators wrote that the fossilized predator was the four-winged flying creature Microraptor gui, already known from other fossils. Since the species was described in 2000, it has been the subject of evolution-based speculation, including ongoing confusion over what its name should be, under what category it should be grouped, what role it may or may not have played in the imaginary evolutionary drama, and even what general class of animal it was.

Fairly typical for an animal of this kind, I think, close as it is to the boundary between birds and non-birds. The chosen words of Mr Thomas – “speculation,” “confusion,” and “imaginary” – are just spin.

Microraptor had long flight feathers on its hind legs, and no such creature inhabits modern zoos. However, the fact that it had flight feathers should have been a major clue as to its basic identity. Only birds sport feathers. It also had a long tail with flattened flight feathers on the end. Such a tail would have stabilized—and was perhaps essential to—a creature with four operational wings. The skeletal anatomy and presence of flight feathers clearly show that Microraptor was a bird, albeit a unique one.

From what I understand the definition of ‘bird’ as ‘animal with feathers’ is nolonger accepted. The dinosaur Shuvuuia was not, by pretty much anybody’s definition, a bird, and yet it had feathers:

Shuvuuia

Additionally, adding ‘flying’ into the mix creates many problems itself, especially to the creationists who must then classify the flightless without being able to say that their ancestors could fly.

So the evolutionary doctrine that dinosaurs evolved into birds must be the main reason why scientists labeled Microraptor a theropod dinosaur, rather than the scientific evidence. By first calling this creature a dinosaur, they can then point to it as an example of a so-called “feathered dinosaur!”

Nonono – the picture above is the ‘feathered dinosaur’ I would (and just did) point to.

Not only have evolutionists blurred the meaning of the word “dinosaur” and failed to identify Microraptor as a bird, some have also suggested that Microraptor was the evolutionary link connecting dinosaurs to birds.

The claim is not in the cited paper, ironically titled ‘Modern’ feathers on a non-avian dinosaur.

This new fossil, however, refutes that idea and reinforces the conclusion that this creature was a bird. First, if Microraptor was evolving from a dinosaur into a more modern-looking bird, then why was a regular two-winged bird found in its rib cage—obviously co-existing with the Microraptor before it became lunch?

Again, I’m not sure who it is that is claiming the Microraptor itself is on the direct line to modern birds. What it is, however, is on a different lineage from a common ancestor that was on the line, and thus may show some traits of said ancestor that other birds don’t have, such as, say, the four-winged thing. I shall have to do a post on this concept.

Also, if Microraptor was transitioning from a land-dwelling dinosaur into a tree-dwelling bird, then why was it already so well-formed that it could successfully hunt, kill, and eat fully formed flying birds? The PNAS authors wrote, “The fact the enantiornithine [the eaten bird] was an adult also suggests that Microraptor was capable of active hunting and was a fairly agile predator.” Obviously, Microraptor was a capable flyer, not a half-evolved pre-bird.

Birds prey on other birds today, and fossils show that they did the same in the past. However, dinosaurs are not known to have eaten birds, since birds could presumably have evaded the ground-dwelling dinosaurs by flying away. Since most dinosaurs couldn’t reach birds, the PNAS authors remarked that “this report of a dinosaur feeding on birds is unique.” But it’s only unique if the definition of “dinosaur” includes birds!

It is not necessary to be able to fly to catch prey that can. Non-flying mammals can eat birds, you know. The mechanism proposed is that Microraptor could climb trees and sneak up on its prey, and that it could also glide from tree to tree. The idea that a transitional form would not be ‘fully functional’ is a persistent creationist myth. To survive an organism needs to be fully functional, as that is what evolution demands.

This fossilized creature swallowed its prey headfirst, “as in most living predatory birds.” Microraptor “was spending a substantial amount of time in the trees” because that’s where birds, not dinosaurs, lived. “Microraptor also had bird teeth and not dinosaur teeth, reinforcing this view.”

What’s funny here is that modern birds don’t have teeth, although early birds did. It’s important to note that the last quote is not from the PNAS paper – it’s from a paper in the creationist Journal of Creation. Microraptor would have been in the trees to hunt birds, not because birds and dinosaurs were segregated.

This fossils shows that Microraptor probably was not flightless, nevertheless “some researchers now embrace the idea that the small ‘theropod dinsoaurs’ with true feathers, especially Microraptor, are really birds, probably flightless.”

Again, quote is from the JoC. The creationists love talking up the likes of Alan Feduccia and others that think that birds are not descended from dinosaurs but from another group – I last covered this in the Caudipteryx post. To summarise, the position seems nowadays rather untenable and based more on attacks on missing pieces of the bird evolution puzzle than providing positive evidence of their own claims.

The new evidence of Microraptor’s predatory flight capability clearly shows that it was a four-winged bird, not a dinosaur—and not an evolutionary transition.

And how many four-winged birds do you know?


I can’t find a DpSU for today (Thursday) on the ICR site as yet.

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