Magical Thinking: Can Pterosaurs Be Darwinized
Baloney detecting is a skill we all learn to some degree and can sharpen with practice. It’s useful, among other areas, in detecting logical and evidentiary flaws in evolutionary interpretations of fossils. Here, let’s think about how evolutionary paleontologists use and abuse concepts of evolution in recent discoveries about pterosaurs.
Neil Thomas has written about “Evolutionary Theory as Magical Thinking” and there is no shortage of examples in the literature on fossils. When reading a scientific paper, one of the first things I do is search through for the use of the word evolution and related words like origin, mutation, transition, and selection. This gives me a sense of the authors’ outlook and where they are headed when it comes to interpreting the data and putting it in context. We start with an article in Current Biology by David Martill, professor of paleobiology at the University of Portsmouth in England.
Keep the Main Thing the Main Thing
When it comes to pterosaurs, surely the most remarkable trait they possessed was powered flight. This multi-faceted, irreducibly complex marvel, Martill informs us, evolved. It just evolved! He couches the magical aspect of his belief in synonyms that not only assume evolution but distract from the marvel of flight and all the engineering requirements to achieve it. A Boeing 747 is said to consist of six million non-flying parts. It’s the engineered arrangement of the parts that permits the function.
Flight, moreover, is an all-or-nothing feat. “You don’t just partly fly,” Paul Nelson quipped in the Illustra film Flight. For a pterosaur to fly, everything about its body had to be designed for that function. Evolutionary paleontologists distract from this most important point through the use of magic words. Martill says (emphasis added),
“Pterosaurs…were the first vertebrates to take to the air”
“Pterosaurs… were the first vertebrates to evolve powered flight”
“Birds… overcame similar problems related to flight”
“…. by becoming better walkers, pterosaurs overcame an evolutionary obstacle”
Did they do these things with foresight and planning? Obviously not. In Darwinism, organisms are the passive beneficiaries of sheer dumb luck. Natalia Jagielska at the University of Edinburgh, whose team found a pterosaur fossil on the Island of Skye (see BBC News), continues the use of magic words in her post at The Conversation:
“…. the first vertebrates to master flight.”
“It took some time for active flight to evolve in the natural world.”
“[in the Triassic,] the first bony animals took to the skies.”
“Birds flapped into existence sometime in the Jurassic….”
“Bats were the last to the race….”
“Pterosaurs were pioneers of flight….”
Günter Bechly referred to this kind of explanation as “Darwinian magic” and found it in probability words such as likely, potentially, and maybe. Jagielska illustrates this talent:
My team’s new study may help solve the evolutionary mystery, revealing how a vane on the tip of their tails may have helped these ancient animals fly more efficiently.
Martill also employs this skill, as do other papers we will look at.
Hiding Gaps with Tarp
Dr. Bechly often pointed out the “explosions” of diversity that are seen in the fossil record: complex organisms and body plans fully formed without ancestors (e.g., here). The pterosaur record is a prime example (here), where the first one was already capable of powered flight. It “looks like they appeared out of thin air,” wrote Bechly (here), as he examined proposed flightless ancestors like Scleromochlus and Venetoraptor. Here, in a Fossil Friday article about Ludodactylus, he said,
Outside of Darwinian fantasy land, we indeed lack any transitional fossils that would document an assumed gradual evolutionary development of characteristic pterosaur wings. In my view this strongly suggests that the transition happened very quickly as an abrupt saltation rather than mediated by hundreds of transitional species, for which there is not a shred of empirical evidence.
Darwinians, by habit, accentuate the positive and eliminate the negative, presenting a distorted view of the record. Do the recent papers present a transitional form from flightless to flying? Do any of the Darwinian experts on pterosaurs use the word transitional? Yes! David Martill does, but only when discussing changes between pterosaurs fully capable of flight, not before them. Moreover, the transition, he argues, happened only in the feet. From this he assumes that grandpappy wing-lizard (the meaning of “pterosaur”) was evolving from landing in trees to walking on the ground. Think of the Darwinian magic such a transition permitted!
Intriguingly, this new pterosaur [Skiphosaura bavarica, announced by David Hone and colleagues] does show some significant modification of the foot skeleton, with dramatic changes to the fifth toe. In basal pterosaurs, the fifth toe is highly elongate, complex, with a 100 degree or more flexure that redirects it posteriorly. In the new pterosaur this fifth toe is reduced, and the bend has all but disappeared, showing a radical restructuring of the foot. This feature also occurs in two other non-pterodactyloids, Douzhanopterus and Propterodactylus, and hints at a more terrestrial lifestyle for these transitional forms.
More Magic Words
All of these specimens were flyers. Martill mentions other differences between them and fellow fossil pterosaurs. Do any of these differences create new organs or flight capabilities? Employing more magic words, Martill makes much ado about some non-flying parts.
This evolutionary transition from climbing to walking was accompanied by other changes achieved at different evolutionary speeds. Notable among these shifts was an increase in the size of the skull, an elongation of the neck, lengthening of the carpus and a reduction in the length of the tail. Later, among the pterodactyloids even more radical shifts occurred, including the evolution of dental filters (as in Pterodaustro from the Cretaceous of Argentina), loss of the dentition in at least two major clades (azhdarchids and pteranodontians), the development of elaborate head crests, as well as ultra-gigantism where wingspans reached more than 9 m in at least two clades: Azhdarchidae and Ornithocheiridae. The analysis of Smyth and colleagues, and the new discovery of Hone and colleagues (and many other pterosaur studies over the last decades) make clear that by becoming better walkers, pterosaurs overcame an evolutionary obstacle that was limiting their ecological diversity. Once over this hurdle, pterosaurs seem to have come down from the trees, became aquatic, adopted an incredible range of feeding strategies, as exemplified by their diverse dentitions, and became giants. Who would have believed that the secret to their evolutionary success was the feet?
Yes, there is diversity among pterosaur species, but Martill assumes those differences in head, teeth, and body size occurred by Darwin’s mutation and selection process.
In their paper in Current Biology, David Hone and colleagues make a big deal about transitions between their prize fossil Skiphosaura and other species, which he says “helps document the transition from early pterosaurs to the pterodactyloids.” This is like pointing out different flight characteristics of jet fighters while ignoring the origin of powered flight in manned aircraft.
In an earlier Current Biology paper, Smyth, Unwin, and colleagues use the word “transition” in a similar way: alleging transitions between pterosaur families while ignoring the origin of flight (though sneaking in Scleromochlus in their phylogenetic tree diagram). While trading in magic words, why not multiply them fourfold?
This transition to predominantly ground-based locomotor ecologies did not occur as a single event coinciding with the origin of short-tailed forms but evolved independently within each of the four principal radiations: euctenochasmatians, ornithocheiroids, dsungaripteroids, and azhdarchoids. Invasion of terrestrial environments by pterosaurs facilitated the evolution of a wide range of novel feeding ecologies, while the freedom from limitations imposed by climbing permitted an increase in body size, ultimately enabling the evolution of gigantism in multiple lineages.
Permission Granted
It’s amazing what little changes in foot bones and finger bones “permitted” Darwin to do with these four groups. They were all powerful flyers, however, before the diversity appeared in the fossils. Smyth says in news from the University of Leicester, “Unlike birds, which must grow before achieving flight, even the smallest Pterodactylus were capable of flight from an early age.” Like Martill and Hone, Smyth only addresses transitions from arboreal to cursorial lifestyles and diets, inferred (not observed, because they are extinct) on the basis of foot bones.
Of interest on a side note, Smyth and Unwin dispute the classification of two species, Pterodactylus antiquus and Diopecephalus kochi, which they regard as “two troublesome taxonomic concepts” (Journal of Systematic Paleontology). We can only wonder what the future will hold for re-evaluating pterosaur phylogeny.
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