Monday, April 8, 2024

How science is - and should not be - done

 Fossil Friday: New Study Confirms “Feathered Dinosaurs” Were Secondarily Flightless Birds

G√ľnter Bechly

April 5a Commons.

This Fossil Friday features one of the most well-known fossils of all, the famous Berlin specimen of the ancient bird Archaeopteryx from the Late Jurassic Solnhofen lithographic limestone in Bavaria. This iconic fossil was often considered to be a missing link between dinosaurs and birds, and thus a poster-child for fossil evidence in favor of Darwinian evolution.

In several past articles at Evolution News I have discussed the work of paleo-ornithologist Alan Feduccia, who courageously challenged the current consensus view that birds evolved from dinosaurs, as first suggested by Yale paleontologist John Ostrom in the mid 1970s with his Birds-are-Maniraptoran-Theropods (BMT) hypothesis. Feduccia elaborated his opposing views in numerous technical articles and four popular books titled “The Age of Birds“ (Feduccia 1980), “The Origin and Evolution of Birds” (Feduccia 1996), “Riddle of the Feathered Dragons” (Feduccia 2012), and most recently “Romancing the Birds and Dinosaurs” (Feduccia 2020). In a highly recommended review of the latter book, James (2021) wrote that “Every school child knows that birds are dinosaurs. Numerous magazine articles and popular books on the topic are available,” which is a remarkable success of selling a relatively recent scientific hypothesis to a wide general audience as an established fact. James continues that “in spite of all this confidence that the problem of the origin of birds has been solved, strong grounds exist for regarding the issue as unsettled, … Surely, admitting that the hypothesis that birds are maniraptoran theropods has serious problems would be better than to defend it so strongly.”

Three General Objections

In a review of Feduccia’s earlier book on the “Riddle of the Feathered Dragons,” Leigh (2014) listed three general objections by Feduccia to Ostrom’s dinosaur-to-bird hypothesis:

1.   Most of the fossils used to support the theropod ancestry of birds are 20 million or more years younger than Archaeopteryx [this was famously labeled by Feduccia as a “temporal paradox”].

2.   Theropod dinosaurs, Deinonychus included, were runners. It is much more reasonable to believe that, like bats and pterosaurs, birds descended from arboreal animals that evolved flight via the ability to glide.

3.   The fossil record suggests that feathers evolved in connection with gliding and flying, rather than as insulation, or as part of an apparatus for catching insects, as Ostrom had suggested.

James (2021) listed several further problems that Feduccia has identified in his most recent book, which support his alternative view:

·         Neoflightless problem: Some flying and flightless birds are being misclassified as theropods.

·         Data analysis problem: Standard phylogenetic analyses are unable to detect complex evolutionary processes like convergence. Flightless birds converge on the body plan of theropods. To estimate basic similarities (homologies), anatomical studies are needed before the phylogenetic analysis.

·         Reduced forelimb problem: Complex characters, once lost, are unlikely to reevolve. Dollo’s Principle.

·         Protofeather problem: “Protofeathers” may be degraded collagen fibers.

·         Digit problem: The frame shift is a verificationist explanation, designed to fit the BMT.

·         Behavior problem: Studies that infer bird-like behavior in dinosaurs are about misidentified birds.

·         Confirmation problem: Scansoriopterygids have no distinctive theropod characters. An assumption that they are theropods is a form of confirmation bias. 

Geist (2022) commented in his review of the same book:

Feduccia leads readers through case after case where scientists, to accommodate the cladograms supporting the BMT hypothesis, have gone to extraordinary lengths to work around data that directly contradict their conclusions. Such efforts violate another bedrock, though not ironclad, philosophy of science: Occam’s Razor, stating that given multiple hypotheses, the simplest of competing theories be preferred over the more complex. Feduccia elegantly illustrates cases where conclusions drawn from cladistic analysis that dictate the connection between birds and dinosaurs violate this principle. At the very least this book might convince supporters of BMT to reevaluate the data.

This failure of cladistics was admitted by John Ostrom (1994: 172) himself, who commented that “reasoning of such dubious quality demonstrates a fundamental flaw in cladistic methodology. Preoccupation with compilation of lengthy lists of shared derived characteristics at the expense of a well-reasoned analysis will result in an erroneous phylogeny every time.”

Responding to Feduccia

So, how did the proponents of the dinosaurian ancestry of birds respond to Feduccia’s profound challenges? They did as Darwinists always do when their pet hypotheses are challenged with actual data: they ridicule and marginalize the critique or reduce it to a straw-man caricature. Here is what Ruben (1997) wrote in his review of Feduccia’s second book:

Specialists who are concerned with avian origins, especially those advocating a dinosaur-bird lineage, will be forced to confront a variety of previously ignored data that argue against this lineage. Thus, it hardly comes as a surprise that the book has been dismissed in recent reviews by several particularly zealous, cladistically oriented paleontologists. However, readers should not be misled by such shenanigans.

Zealous shenanigans? This is quite revealing for an alleged unbiased quest for scientific truth.

The Neoflightless Hypothesis

But, how does Feduccia explain the indisputable great similarity between vane-feathered bipedal dinosaurs (called Pennaraptora) and true birds? Actually, he does not dispute a close relationship at all, but suggests that Pennaraptora were not theropod dinosaurs but rather secondarily flightless birds, which he called the neoflightless hypothesis. Incidentally, the same claim has been made by skeptics of Darwinian evolution.

Now, a new study by Kiat & O’Connor (2024) published in the Proceedings of the National Academy of Sciences provides strong additional support to the neoflightless hypothesis (also see the press releases by Field Museum 2024 and Koumoundouros 2024). The scientists studied the wing feathers in hundreds of different living bird species of all major orders, and detected a simple pattern that reliably distinguishes secondarily flightless birds from those that can fly: the latter always have 9-11 asymmetrical flight feathers called primaries, while the former have either significantly more or none at all. Furthermore, the degree of primary vane asymmetry turned out to be strongly related to flight. This allowed the researchers to look at 65 species of fossil birds and feathered dinosaurs to estimate their ability to fly. Unsurprisingly, Archaeopteryx and the four-winged Microraptor passed the litmus test for flight.

Much more surprisingly, the study suggests that feathered dinosaurs like “Caudipteryx possessed the correct number of primary feathers but they were almost completely symmetrical, ‘almost certainly’ ruling out flight” (Koumoundouros 2024). The authors concluded that “applying these data to extinct pennaraptorans suggests that anchiornithines and the oviraptorosaur Caudipteryx are secondarily flightless. The phylogenetic position of these species suggests that volant abilities are plesiomorphic to Pennaraptora.” In other words, all those feathered dinosaurs originally had wings like birds and could fly, and thus do not represent transitional stages in the evolution of avian flight from cursorial dinosaurs. They are no help at all to explain the origin of pennaceous feathers and wings. This also makes very recent studies obsolete, which proposed scenarios to derive the bird wing from more primitive structures in maniraptoran dinosaurs, such as the propatagium in Caudipteryx and Microraptor (Uno & Hirasawa 2023, also see University of Tokyo 2023). As new data accumulate at an ever faster rate, the shelf life of evolutionary story telling is plummeting from decades to only months.

Trust the Science?

Should you really just trust the science (but not too long)? Alan Feduccia can rightfully claim an important empirical confirmation of his theory, and Darwinists may have to say goodbye to some cherished assumed transitional forms and the evolutionary just-so stories built upon them. But there is more: Kiat & O’Connor (2024) explicitly admit that “the results of these analyses support a single origin of dinosaurian flight and indicate the early stages of feathered wing evolution are not sampled by the currently available fossil record.” It looks very much like flying vertebrates with feathered wings appeared fully formed and abruptly in the Jurassic, which resonates perfectly with intelligent design theory, but with Darwinism (in the sense of unguided gradual evolution) not so much.