Rosa Rubicondior: Refuting Creationism - More Pterrible News For Creationists As Scientists Track The Evolution of Terrestrial Pterosaurs

Ptero Firma: footprints pinpoint when ancient flying reptiles conquered the ground | News | University of Leicester

False-colour depth map revealing the shape and pressure of each step, showing that these creatures bore more weight on their hands while walking.

Most people—apart, perhaps, from creationists who deny such creatures ever existed—are aware that a group of reptiles evolved the ability to fly and took to the skies long before birds and bats emerged to exploit this medium.

What many people don’t know, however, is that some members of this group, including larger species, later returned to land and adopted a coastal wading lifestyle. We know this because their fossilised tracks have been found preserved in what was once coastal mud.

Young Earth creationists routinely point to geological formations derived from coastal or estuarine mud as 'evidence' of a supposed global flood, yet they consistently fail to explain how such a flood could have preserved so many footprints—left by waders such as ducks, geese, redshanks, and sandpipers—as well as delicate raindrop impressions. Even harder to explain is the evidence showing that these footprints were made at different times, spanning several million years, up until the mass extinction caused by an asteroid impact 66 million years ago.

And disconcertingly for creationists, a team of palaeontologists led by Robert Smyth, a doctoral researcher in the Centre for Palaeobiology and Biosphere Evolution (School of Geography, Geology and the Environment) at the University of Leicester, has demonstrated that these fossil footprints can be used to trace the evolutionary history of the pterosaurs that made them.

What information do you have on the evolution and extinction of the pterosaurs? Pterosaurs were the first vertebrates to evolve powered flight, appearing in the Late Triassic, about 225 million years ago, and going extinct at the end of the Cretaceous, around 66 million years ago, alongside non-avian dinosaurs.

Here’s a structured overview of their evolution and extinction:

Origins and Early Evolution

Ancestry: Pterosaurs are archosaurs, the group that also includes dinosaurs and crocodilians. They likely evolved from small, bipedal archosaurs, but their precise ancestors remain unclear due to a sparse early fossil record.
First known pterosaurs: Eudimorphodon and Preondactylus, from the Late Triassic, were small with long tails and many teeth. These early forms suggest a gliding ancestry that eventually led to powered flight.

Flight and Adaptations

Wings: Their wings were formed by a membrane of skin and muscle stretching from an elongated fourth finger down to the hind limbs or body. Unlike birds, they had no feathers.
Lightweight skeleton: Pterosaurs had hollow bones to reduce weight.
Varied diets: They evolved a range of feeding strategies—fish-eating, filter-feeding, insectivory, scavenging, and even frugivory or carnivory.
Crest and headgear: Some species, like Pteranodon and Tapejara, had elaborate cranial crests, likely for display or species recognition.

Diversification

Pterosaurs underwent two major evolutionary radiations:

Rhamphorhynchoids (early forms):

Appeared in the Triassic and were dominant in the Jurassic.
Typically small with long tails and toothed jaws.
Example: Rhamphorhynchus.

Pterodactyloids (advanced forms):

Appeared in the Late Jurassic and became dominant in the Cretaceous.
Larger, with short tails and a wider range of body sizes and niches.
Included Pteranodon, Quetzalcoatlus (among the largest flying animals ever), and Dsungaripterus.

Ecological Roles

Pterosaurs occupied aerial and coastal ecological niches and some likely foraged inland. Recent fossil evidence, including footprints, shows that some were adept at walking and wading, supporting semi-terrestrial behaviours, particularly in later species.

Extinction

Event: Pterosaurs went extinct during the Cretaceous–Paleogene (K–Pg) mass extinction, caused by a massive asteroid impact near modern-day Chicxulub, Mexico.
Reason for extinction: While pterosaurs were still diverse in the Late Cretaceous, they may have faced increasing competition from birds, especially in smaller ecological niches. However, they remained successful up to the extinction event.

Fossil Record and Challenges

The fossil record is patchy due to their fragile bones, which don’t fossilise easily.
However, recent discoveries, including soft tissues and embryos, have greatly improved our understanding of their biology and development.

Their findings are published in a paper in Current Biology, and further explained in a University of Leicester news release.

Ptero Firma: footprints pinpoint when ancient flying reptiles conquered the ground
Fossils of footprints over 160 million years old have helped palaeontologists at the University of Leicester to narrow down when pterosaurs adapted to live on the ground.

These awe-inspiring flying reptiles of the Mesozoic era are often imagined soaring over the heads of dinosaurs. But new research shows that some of these ancient creatures were just as comfortable walking on the ground.
In a groundbreaking new study published today in Current Biology (1 May), scientists at the University of Leicester have successfully linked fossilised footprints to the types of pterosaurs that produced them. By using 3D modelling, detailed analysis, and comparisons with pterosaur skeletons, the team has shown that at least three different types of tracks match up with distinct groups of pterosaurs.

The new study supports the idea that pterosaurs underwent a major ecological shift during the middle part of the Age of Dinosaurs, about 160 million years ago, with several groups becoming more terrestrial.

Footprints offer a unique opportunity to study pterosaurs in their natural environment. They reveal not only where these creatures lived and how they moved, but also offer clues about their behaviour and daily activities in ecosystems that have long since vanished.

Dr. Robert S. H. Smyth, lead author
Centre for Palaeobiology & Biosphere Evolution
School of Geography, Geology, and the Environment
University of Leicester, Leicester, UK.

Pterosaur tracks meet their match. Where ancient footprints meet their maker. A side-by-side comparison of a pterosaur’s hand and foot with 155-million-year-old tracks from Wyoming, USA. The false-colour depth map reveals the shape and pressure of each step, showing that these creatures bore more weight on their hands while walking.

The study uncovered three distinct types of pterosaur footprints, each shedding light on different lifestyles and behaviours. By linking footprints to specific groups, scientists now have a powerful new way to study how these flying reptiles lived, moved, and adapted to different ecosystems across time.

Finally, 88 years after first discovering pterosaur tracks, we now know exactly who made them and how.

Dr David M. Unwin, co-author
Centre for Palaeobiology & Biosphere Evolution
School of Geography, Geology, and the Environment
University of Leicester, Leicester, UK.

Perhaps the most striking discovery comes from a group of pterosaurs called neoazhdarchians which includes Quetzalcoatlus, with a 10 m wingspan one of the largest flying animals ever to have existed. Their footprints have been found in coastal and inland areas around the world, supporting the idea that these long-legged creatures not only dominated the skies but were also frequent ground dwellers, inhabiting the same environments as many dinosaur species. Some of these tracks are present right up until the asteroid impact event, 66 million years ago, which led to the extinction of both pterosaurs and dinosaurs.

One group of pterosaurs, ctenochasmatoids, known for their long jaws and needle-like teeth, left behind tracks most commonly found in coastal deposits. These animals likely waded along muddy shores or in shallow lagoons, using their specialised feeding strategies to catch small fish or floating prey. The abundance of these tracks suggests that these coastal pterosaurs were far more common in these environments than their rare bodily remains indicate.

Another type of footprint was discovered in rock layers that also preserve the fossilised skeletons of the same pterosaurs. The close association between the footprints and skeletons provides compelling evidence for identifying the print makers. Known as dsungaripterids, these pterosaurs had powerful limbs and jaws, with toothless, curved beak tips designed for prising out prey, while large, rounded teeth at the back of their jaws were perfect for crushing shellfish and other tough food items.

Tracks are often overlooked when studying pterosaurs, but they provide a wealth of information about how these creatures moved, behaved, and interacted with their environments. By closely examining footprints, we can now discover things about their biology and ecology that we can't learn anywhere else.

Dr. Robert S. H. Smyth.

A skeletal reconstruction of a comb-jawed pterosaur walking across an ancient mudflat, its posture and movement informed by fossil trackways.
Publication:

Smyth, Robert S.H.; Breithaupt, Brent H.; Butler, Richard J.; Falkingham, Peter L.; Unwin, David M.
Identifying pterosaur trackmakers provides critical insights into mid-Mesozoic ground invasion.
Current Biology, DOI: 10.1016/j.cub.2025.04.017

Highlights

Pterosaur trackmakers are identified using quantitative methods and diagnostic traits
Three track morphotypes match pterosaur clades inferred as most terrestrially adapted
Tracks support a mid-Mesozoic radiation of pterosaurs into terrestrial ecosystems
Identifying trackmakers transforms our view of pterosaur biogeography and ecology

Summary
Fossilized tracks have provided unique insights into the distribution, behavior, and ecology of extinct taxa. Moreover, because they are abundant and often have distinct distributions in time and space compared with the body fossil record, they have considerable potential for testing and extending macroevolutionary hypotheses. The key to unlocking this vast potential lies in reliably linking tracks to their producers, but this remains a persistent challenge. This limitation is particularly evident among pterosaurs, the dominant flying vertebrates of the Mesozoic. Despite an extensive record of pterosaur tracks spanning more than 100 million years, the identities of trackmakers are unclear in most cases, limiting their use for addressing key questions about pterosaur ecology and evolution. In this study, we employ quantitative analyses and diagnostic features of pedal anatomy to directly link three distinct pterosaur track morphotypes to specific pterodactyloid clades: ctenochasmatoids, dsungaripterids, and neoazhdarchians. These results considerably extend the known biogeographic distribution of these clades, supporting macroevolutionary and ecological hypotheses derived from analyses of the body fossil record. The absence of pterosaur tracks prior to the Middle Jurassic supports evidence from hand and foot morphology indicating that early pterosaurs were arboreal or scansorial. Track evidence demonstrates a major radiation of derived pterodactyloid pterosaurs into terrestrial niches beginning in the Middle Jurassic. Successive clades maintained a strong presence across diverse terrestrial environments throughout the latter half of the Mesozoic, highlighting the evolutionary versatility and ecological significance of pterosaurs in terrestrial environments.

Introduction
Pterosaurs, flying archosaurian reptiles, were among the most successful tetrapod groups of the Mesozoic (227–66 million years ago [mya]).^1,2,3 Historically, their flight capabilities, combined with profound preservation biases,⁴ often led to them being interpreted as aerial specialists closely associated with marine environments.⁵ Pterosaurs were frequently considered ineffectual on the ground, with minimal influence on, or interaction with, terrestrial ecosystems.^6,7 This traditional perspective suggested that the evolution of flight constrained, rather than expanded, their ecological roles.

However, re-evaluation of pterosaur tracks around the turn of the millennium revealed that at least some species were proficient terrestrial locomotors, employing a quadrupedal gait to navigate on the ground (Figure 1).^{8,9,10,11,12,13} These discoveries sparked a renewed wave of research into pterosaur paleobiology, inspiring novel hypotheses about their ecological roles. Reassessments of skeletal morphology,^{3,14,15,16,17,18,19} flight diversity,²⁰ and dietary adaptations^21,22 have since demonstrated that pterosaurs occupied a far broader range of ecological niches than previously recognized. Far from being an evolutionary constraint, the development of flight enabled pterosaurs to exploit not only aerial niches but also a wide diversity of terrestrial habitats and ecological roles.¹⁹ This reflects a major shift in our understanding and has profound implications for pterosaur evolutionary history, as well as the nature of their involvement in Mesozoic terrestrial ecosystems.

Figure 1 Terrestrial locomotion and track morphology of pterodactyloid pterosaurs

(A) Reconstruction of the ctenochasmatoid pterosaur Ctenochasma elegans walking using an ipsilateral gait in which fore and hind limbs on the same side of the body move together as pairs.
(B) Manual and pedal morphology of Ctenochasma elegans. The pes is plantigrade and pentadactyl, whereas the manus is digitigrade and functionally tridactyl, as the large fourth digit, which supports the outer wing, is folded away during terrestrial locomotion.
(C) Height map of pterosaur manus and pes footprints in the holotype of the ichnotaxon Pteraichnus stokesi (UW 12368), exhibiting a morphology consistent with that of Ctenochasma elegans.
(D) Height map of part of a pterosaur trackway, CR99.43 (Pteraichnus isp.), from the Upper Jurassic Cazals Formation of Crayssac, France.
(E) Interpretive outline drawing of CR99.43.
Range in elevation for (C) and (D) is presented in millimeters. Scale bars: 20 mm in (C) and 200 mm in (D) and (E).

The pterosaur track record made foundational contributions to modern pterosaur paleontology by settling long-standing debates about terrestrial locomotion that paleontologists had failed to resolve through body fossils alone. Subsequently, however, work on pterosaur tracks has become largely disconnected from the main body of pterosaur research. This separation might imply that, having answered the fundamental question about pterosaur terrestrial locomotion, the track record offers little further insight into pterosaur paleobiology. Moreover, most research on pterosaur ecology has predominantly focused on feeding^21,22,23 and flight.^20,24 Although these aspects are crucial, limited knowledge of terrestrial locomotion and habitat use has left a significant gap in our understanding of broader pterosaur ecology.

Over the past 30 years, many new occurrences of pterosaur tracks have been discovered, to the point that tracks potentially rival body fossils in terms of material abundance.^25,26 This rich record represents a unique and underutilized source of data for pterosaur paleobiology. Unlike body fossils, which can be moved from their original location, tracks usually remain in the same place where they were formed.

As a result, tracks offer unparalleled information about the behavior, movement, and interactions of extinct animals as living animals in their natural habitats, capturing aspects of their lives that body fossils alone cannot reveal.^{27,28,29,30,31} Pterosaur tracks also remain neglected in broader paleontological studies. Tracks are often preserved in depositional environments that differ distinctly—stratigraphically, geographically, and ecologically—from those yielding body fossils. However, these data have not yet been successfully incorporated into studies of pterosaur distribution,³² ecology,³³ and macroevolution.^34,35

This absence is not without justification. A major obstacle to integrating the body fossil and ichnological records is the difficulty of reliably assigning tracks to specific pterosaur clades. It is generally assumed that all known pterosaur tracks were made by pterodactyloids,^2,36,37 although this assumption is not universally accepted^14,25,38 and requires further testing. Attempts to assign tracks to particular clades have typically relied on circumstantial evidence, such as the absolute size of the tracks or their stratigraphic age,³⁹ rather than detailed morphological or quantitative analyses. In rare instances, simple morphological comparisons have been made between tracks and specific body fossil taxa.^40,41 However, in these cases, the co-occurrence of pterosaur skeletal material and tracks within the same stratigraphic units is often a more convincing justification for assignment than the analyses performed.

Recent advancements in quantitative^42,43 and synapomorphy-based^44,45,46 methods have improved trackmaker assignments for some groups. However, pterosaur trackmaker identification has lagged behind. This is largely due to limited research on the variability of their hands and feet, as well as incomplete adoption of modern three-dimensional (3D) documentation techniques.⁴⁷

In this study, we apply quantitative multivariate analyses and synapomorphy-based methodologies to the global pterosaur track record to identify trackmakers. A newly compiled dataset of pterosaur autopodia enables comprehensive comparisons of skeletal and track records using these approaches. Exceptionally well-preserved tracks can be confidently assigned to specific clades, while even less well-preserved tracks are often attributable to groups based on recognized synapomorphies. The results of this critical reassessment permit testing of the hypothesis that pterosaurs experienced a major ecological shift during the Middle Jurassic.

Smyth, Robert S.H.; Breithaupt, Brent H.; Butler, Richard J.; Falkingham, Peter L.; Unwin, David M.
Identifying pterosaur trackmakers provides critical insights into mid-Mesozoic ground invasion.
Current Biology, DOI: 10.1016/j.cub.2025.04.017

Copyright: © 2025 The authors.
Published by Elsevier Inc. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)

This new research by Robert Smyth and colleagues, presents a significant challenge to creationist claims—especially those rooted in Young Earth Creationism—because it provides clear, physical evidence of evolutionary change over deep time, preserved in the fossil record. By analysing fossilised pterosaur footprints found in what was once coastal mudflats, the researchers have shown that not only were these flying reptiles capable of life on land, but their tracks also reveal a gradual shift in locomotion and body structure over millions of years. This is precisely the kind of transitional, cumulative change that evolutionary theory predicts—and which creationist models consistently deny or ignore.

What makes this especially problematic for creationism is the nature of the evidence itself. Fossilised footprints are not bones or teeth that could be argued to have been transported or reburied—they are direct, in situ traces of behaviour left in soft sediment, later preserved as rock. These trace fossils show a sequence of adaptations in gait and stance that correspond to changes in anatomy documented from skeletal remains, providing two independent lines of evolutionary evidence. The study demonstrates that terrestrial movement became more efficient in certain pterosaurs over time, supporting a scenario of adaptive evolution rather than sudden creation.

Moreover, these footprints are found in well-dated, stratified layers of sediment spanning tens of millions of years. This extended timescale directly contradicts the creationist assertion that all life was created within a single week a few thousand years ago, and that most fossils were laid down during a single global flood. The idea that a worldwide deluge could randomly preserve a coherent evolutionary sequence of footprints—some laid down millions of years apart, including delicate raindrop impressions and repeated trackways of multiple species—is not only implausible but defies all known geological principles.

In sum, this research reinforces the reliability of evolutionary science and the geological timescale, while simultaneously exposing the inadequacy of creationist explanations. It exemplifies how careful, evidence-based science continues to illuminate the deep history of life on Earth, while creationist claims grow increasingly detached from the fossil record.

Advertisement

Amazon