A 2011 ‘catalog of pterosaur pedes for trackmaker identification’ revisited in 2025

Back in 2011
Peters published ‘A catalog of pterosaur pedes for trackmaker identification’ Ichnos 18:2, 114–141. Peters reported, “Traces attributed to pterosaurs have been studied for more than 50 years, but little interest has been shown in the pedes themselves. While ichnites can vary greatly in their correspondence to their trackmaker, most pterosaur tracks
appear to preserve sufficient detail to assess their origins. Distinct pedal characters indicate certain tiny pterosaurs were not juveniles of dissimilar adults, but were separate taxa and likely adults themselves.”

Figure 1 in Peters 2011 included 24 pterosaur and pre-pterosaur tracks and trackmakers. Some examples included pre-pterosaurian pedes and pre-pterosaurian tracks like Early Triassic Rotodactylus (Peabody 1948) and Liassic = Early Jurassic Sauria aberrante (Casamiquela 1962).
Figure 2 added 11.
Figure 3 added 31.
Figure 4 added 18.
Figure 5 added 23.
Figure 6 added 17.
Figure 7 added 5 for a total of 129.

This work followed Unwin 1989 and other contemporary authors
who weighed in on Pteraichnus tracks (Stokes 1957). Some workers agreed on their pterosaurian origin. Others disagreed, assigning them to crocodilomorphs (see Peters 2011 and/or Smyth et al 2025 for citations).

Despite its potential for usefulness, Peters 2011 was rarely cited since then until…

Smyth et al (co-authors including his professor, DM Unwin) 2025
updated Peters 2011 by matching a few tracks to trackmakers described since 2011 (Figs 1, 2).

In doing so Smyth et al 2025 broke Bennett’s curse (private communication ca 2000) to independent researcher Peters:  “You will not be published and if you are published, you will not be cited.”

I only hope Bennett will forgive Smith et al for this citation transgression.

Figure 1. Pteraichnus track, Late Jurassic Sundance Fm from Smyth et al 2025. Frames 3 and 4 are freehand interpretations from Smyth et al. Frames 5 and 6 are DGS tracings overlaid by estimated bone elements and PILs (parallel interphalangeal lines). Note digit 1 is longer than 3, rare in pterosaurs except taxa transitional from scaphoganthids to cycnorhamphids, all of which had a large pedal digit 5. ” data-image-caption=”

Figure 1. Pteraichnus track, Late Jurassic Sundance Fm from Smyth et al 2025. Frames 3 and 4 are freehand interpretations from Smyth et al. Frames 5 and 6 are DGS tracings overlaid by estimated bone elements and PILs (parallel interphalangeal lines). Note digit 1 is longer than 3, rare in pterosaurs except taxa transitional from scaphoganthids to cycnorhamphids, all of which had a large pedal digit 5.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif?w=211″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif?w=584″ class=”size-full wp-image-92753″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif” alt=”Figure 1. Pteraichnus track, Late Jurassic Sundance Fm from Smyth et al 2025. Frames 3 and 4 are freehand interpretations from Smyth et al. Frames 5 and 6 are DGS tracings overlaid by estimated bone elements and PILs (parallel interphalangeal lines). Note digit 1 is longer than 3, rare in pterosaurs except taxa transitional from scaphoganthids to cycnorhamphids, all of which had a large pedal digit 5.” width=”584″ height=”829″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif?w=584&h=829 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif?w=106&h=150 106w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif?w=211&h=300 211w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/unwin.ptero588-1.gif 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 1. Pteraichnus track, Late Jurassic Sundance Fm from Smyth et al 2025. Frames 3 and 4 are freehand interpretations from Smyth et al. Frames 5 and 6 are DGS tracings overlaid by estimated bone elements and PILs (parallel interphalangeal lines). Note digit 1 is longer than 3, rare in pterosaurs except Balaeognathus and taxa transitional from scaphoganthids to cycnorhamphids, all of which had a large pedal digit 5. Here digit 5 was imagined by Smyth et al as it bears no resemblance to their data. The pads were also shifted.

Smyth et al matched
the trackmaker of the Late Jurassic Sundance ichnite, UW 39958 (Fig 1) to Balaenognathus (Fig 2), a pre-Pterodaustro ctenochasmatid in the LRT described by Martill et al 2023.

In Balaenognathus the re-spreading of the digits (Fig 2) shows how they align with PILs, but not when the freehand interpretation by Smyth et al is overprinted.
Lesson here: strictly follow the data. Avoid using freehand figures for data.

Figure 2. How Smyth et al ‘matched’ their Sundance Fm track to Balaenognathus from Martill et al 2023. ” data-image-caption=”

Figure 2. How Smyth et al ‘matched’ their Sundance Fm track to Balaenognathus from Martill et al 2023.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif?w=584″ class=”size-full wp-image-92755″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif” alt=”Figure 2. How Smyth et al ‘matched’ their Sundance Fm track to Balaenognathus from Martill et al 2023.” width=”584″ height=”520″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif?w=584&h=520 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif?w=150&h=134 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif?w=300&h=267 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/balaenognathus.pes_.insitu588.gif 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 2. How Smyth et al ‘matched’ their Sundance Fm track to Balaenognathus from Martill et al 2023.

Furthermore
Smyth et al matched a narrow 15cm long plantigrade trace from Aptian (Mid-Cretaceous) China, Pteraichnus yanguoxiaensis (UCM 214.53) to an Early Cretaceous shenzhoupterid, Meilifeilong (Fig 3). again using a freehand pedal skeleton drawing.

The authors considered all shenzouperids to be close to the azhdarchid, Chaoyangopterus, which had long, narrow, plantigrade pedes with small toes. In the large pterosaur tree (LPT) shenzhoupterids were derived from digitigrade germanodactylids, not far from digitigrade dsungaripterids, like Noripterus (Fig 3). In any case there are better matches for the Chinese ichnite, probably among the chaoyangopterids

Figure 3. From figure 5 in Smyth et al 2025 showing from left to right Pteraichnus yanguoxiaensis (UCM 214.53), interpretation of same and freehand illustration of the right pes of Meilifeilong (DB0233). Added here is a DGS colored image of the right pes of Meilifeilong, the same removed from the matrix and below a 3D paper model of same compared to a similar model of Noripterus, a digitigrade dsungaripterid. ” data-image-caption=”

Figure 3. From figure 5 in Smyth et al 2025 showing from left to right Pteraichnus yanguoxiaensis (UCM 214.53), interpretation of same and freehand illustration of the right pes of Meilifeilong (DB0233). Added here is a DGS colored image of the right pes of Meilifeilong, the same removed from the matrix and below a 3D paper model of same compared to a similar model of Noripterus, a digitigrade dsungaripterid.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg?w=262″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg?w=584″ class=”size-full wp-image-92768″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg” alt=”Figure 3. From figure 5 in Smyth et al 2025 showing from left to right Pteraichnus yanguoxiaensis (UCM 214.53), interpretation of same and freehand illustration of the right pes of Meilifeilong (DB0233). Added here is a DGS colored image of the right pes of Meilifeilong, the same removed from the matrix and below a 3D paper model of same compared to a similar model of Noripterus, a digitigrade dsungaripterid.” width=”584″ height=”669″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg?w=584&h=669 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg?w=131&h=150 131w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg?w=262&h=300 262w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/meilifeilong.track588-1.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />

Figure 3. From figure 5 in Smyth et al 2025 showing from left to right Pteraichnus yanguoxiaensis (UCM 214.53), interpretation of same and freehand illustration of the right pes of Meilifeilong (DB0233). Added here is a DGS colored image of the right pes of Meilifeilong, the same removed from the matrix and below a 3D paper model of same compared to a similar model of Noripterus, a digitigrade dsungaripterid. Take a close look at tiny pedal digit 5 of Meilifeilong. The freehand illustration by Smyth et al missed the details.

Figure 4 in Smyth et al
matched the 4cm long Early Cretaceous digitigrade track Pteraichnus wuerhoensis (IVPP V 26281.2 58PR) to the mismatched 6cm long pes of Noripterus (Fig 3). We looked at Pteraichnus wuerhoensis earlier here and matched them to late-surviving Rhamphorhynchus specimens.

Figure 1a in Smyth et al
illustrated the traditional quadrupedal pterosaur making tracks bent over so much that the hands were unable to get behind the shoulder to produce a forward thrust vector, following the example provided by Bennett 1997 animated here.

Walking pterosaur according to Bennett ” data-image-caption=”

Figure 4. Click to animate. Walking pterosaur according to Bennett. Note the forelimbs provide no forward thrust, but merely act as props.

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif?w=576″ class=”size-full wp-image-1020″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif” alt=”Walking pterosaur according to Bennett” width=”576″ height=”315″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif 576w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif?w=150&h=82 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/bennettpterodac-walk.gif?w=300&h=164 300w” sizes=”(max-width: 576px) 100vw, 576px” />

Figure 4. Click to animate. Walking pterosaur according to Bennett. Note the forelimbs provide no forward thrust, but merely act as props. No tetrapods walk like this, constantly braking pterosaur.

This competes with
the animation matched to Crayssac tracks of a more upright pterosaur trackmaker, using its forelimbs more like ski poles (Fig 5) following its upright bipedal origins, feet oriented below the center of balance – like birds.

Pterodactylus walk matched to tracks according to Peters ” data-image-caption=”

Figure 6. Click to animate. Plantigrade and quadrupedal Pterodactylus walk matched to tracks

” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif?w=305″ class=”size-full wp-image-1021″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif” alt=”Pterodactylus walk matched to tracks according to Peters” width=”305″ height=”161″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif 305w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif?w=150&h=79 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2011/08/pterodacwalk_small.gif?w=300&h=158 300w” sizes=”(max-width: 305px) 100vw, 305px” />

Figure 5. Plantigrade and quadrupedal Pterodactylus walk matched to tracks

Quotes from the paper
“pterosaur trackmaker identification has lagged behind. This is largely due to limited research on the variability of their hands and feet”

Peters 2011 focused on 129 pterosaurs and their tracks.

“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.”

Rotodactylus tracks from the Early Triassic are not mentioned in the text.

“Pterosaurs, flying archosaurian reptiles.”

This was disproved by phylogenetic analysis (Peters 2000, 2007. 2011). Pterosaurs are infamous for not sharing traits with archosaurs, and yet this myth persists in academia.

“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.”

“profound implications” = scientific puffery.

“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.”

That implies that until this paper, pterosaur workers were befuddled. Not true. Pterosaurs put one foot in front of the other, like other tetrapods. Peters 2011 traced pterosaurs back to the Early Triassic ancestors and ichnite makers, both ignored by Smyth et al despite having Peters 2011 on their shelf.

“work on pterosaur tracks has become largely disconnected from the main body of pterosaur research”

Not true. Intimately intertwined.

“Pterosaur tracks also remain neglected in broader paleontological studies.”

Here the authors are purposefully omitting work on pterosaur feet and tracks by Padian 1983, Peters 2000, 2003, 2010.

“However, pterosaur trackmaker identification has lagged behind.”

Here the authors are purposefully omitting work on pterosaur feet and tracks by Peters 2000, 2003, 2010, 2011.

“The results of this critical reassessment permit testing of the hypothesis that pterosaurs experienced a major ecological shift during the Middle Jurassic.”

That’s the time of Dorygnathus and Campylognathoides – neither of which is mentioned in the text. Pterosaur tracks are not yet known from this era.

“Nevertheless, the elongated digit III of most pterosaur manus prints indicates that the trackmakers had strongly ectaxonic manual digits.”

Definition: ectaxonic = Having the outer digits more strongly developed than the inner ones. Which clade has ectaxonic manual digits? Not archosaurs. Lepidosaurs.

“it does suggest that clades with more equally proportioned manual digits, such as anurognathids, scaphognathines, istiodactylids, and ornithocheirids, are not likely to have produced any of the pterosaur tracks reported to date.”

Peters 2011 assigned fossil ichnites to anurognathids and ornithocheirids.

“Pterosaur footpads had a predominantly arthral arrangement, with each pad placed at the position of a metatarsophalangeal (MTP) or interphalangeal (IP) joint.”

Take a look at the photos above to see if they agree with the Smyth et al illustrations.

A modern analog from Pittman et al 2022, “Two main types of toe pad arrangement are typically present in modern birds. The arthral condition, in which the toe pad is aligned with the interphalangeal joint, is characteristic of the raptorial species. The mesarthral condition, in which the toe pad is aligned with the phalanx itself is found in non-raptorial forms.”

“The second category of purported non-pterodactyloid tracks including Rhamphichnus ispp., are not pterosaurian.‘

This confirms findings from 2020 first reported here.

“Peters 2011 assigned numerous tracks to both non-pterodactyloid and pterodactyloid trackmakers. However, reliance on idiosyncratic digital reconstruction methods, which diverge from well-established anatomical and ichnological morphology,131–133 undermine the conclusions of this work. Like previous studies, our direct examination of the material could not identify many of the proposed features in pterosaur skeletal anatomy and track morphology, casting significant doubt on the validity of these trackmaker assignments.”

This is so vague. Don’t be vague. Tackle every issue with every taxon with specific criticism. Intend your remarks to help your colleagues, not to dismiss their peer-reviewed published works in toto.

Tracks are variable, vague and have to be interpreted. The balance between fact and opinion can swing when it goes through the human filter.

The problem is: a few academics let me publish back then because they saw the value, while others have regretted it ever since, perhaps because I showed how accessible paleontology is. Those publications proved that you didn’t need a degree and a PhD program under the tutelage of a professor to publish in a long list of academic journals and make discoveries that were ostensibly reserved for them.

“idiosyncratic digital reconstruction methods” = tracings of specimens using Photoshop, which everyone does now as standard methodology. On the other hand, Smyth et al 2025 created freehand reconstructions that more or less departed from the data, as shown above.

Quotes from the publicity
“Some of the largest animals to ever take to the air actually spent much of their time on the ground, a new study claims.”

The largest pterosaurs were flightless, so spent ALL their time on the ground.

“Researchers at the University of Leicester have been examining the tracks left by a type of pterosaur called Quetzalcoatlus, which had a wingspan of up to 10m (32ft).”

Quetzalcoatlus was not mentioned in the text, but was in the citations.

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

More puffery. Peters 2011 reviewed more tracks and trackmakers. See above.

Final thought:
“Battles are so bitter in Academia because the stakes are so low.” – Sayre’s law 1973

References
Bennett SC 1997. Terrestrial locomotion of pterosaurs: a reconstruction
based on Pteraichnus trackways. J. Vertebr. Paleontol. 17, 104–113.
Martill DM (4 co-authors 2023. A new pterodactyloid pterosaur with a unique filter feeding apparatus from the Late Jurassic of Germany. PalZ. 97, 383–424.
Peabody FE 1948. Reptile and amphibian trackways from the Lower Triassic Moenkopi formation of Arizona and Utah. University of California Publications, Bulletin of the Department of Geological Sciences, 27: 295–468.
Peters D 2011. A Catalog of Pterosaur Pedes for Trackmaker Identification. Ichnos 18:2, 114–141.
Smyth RSH et al (4 co-authors) 2025. Identifying pterosaur trackmakers provides critical insights into mid-Mesozoic ground invasion. Current Biology 35, 1–17.
Stokes WL 1957. Pterodactyl tracks from the Morrison Formation. Journal of Palaeontology, 31: 952–954.
Unwin DM 1989. A predictive method for the identification of vertebrate ichnites and its application to pterosaur tracks. In Gillette, D. D. and Lockley, M. G. (eds.). Dinosaur Tracks and Traces. Cambridge University Press, Cambridge, pp. 259–274.

Publicity
BBC.com
phys.org/news

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