New research suggests that colourful tapejarid pterosaurs may have been even more spectacular than previously imagined. A recently published study proposes that some of these flying reptiles possessed iridescent pycnofibres that produced shimmering colours. As a result, these structures may have played an important role in visual signalling and display.

The bodies of pterosaurs, the first vertebrates to achieve powered flight, are covered with integumentary filaments (pycnofibres). They are thought to be homologous with feathers associated with the Dinosauria.

The Age of Dinosaurs Deluxe Caiuajara pterosaur figure with a moveable jaw. Tapejarid pterosaurs like Caiuajara have been depicted with colourful crests, however, a recent study (May 2026) proposes that the pycnofibres covering their bodies may have been iridescent.

The image (above) shows the CollectA Supreme Deluxe Caiuajara figure.  It is pronounced – Kay-you-ah-jar-rah.  CollectA have introduced an extensive range of beautiful pterosaur scale models.

To view the CollectA Deluxe model range: Scale Models of Pterosaurs and Other Prehistoric Animals.

Colourful Tapejarid Pterosaurs

The Tapejaridae were a geographically widespread Early Cretaceous pterosaur family with probable Asian origins.  Tapejarid fossil material is known from the UK, Europe, Africa, South America and possibly from North America too.  All known tapejarids were edentulous (lacked teeth). These pterosaurs are famed for their large and flamboyant crests.  A recently published paper suggests that pycnofibres covering their bodies may have been capable of iridescence.  If this is the case, they would have been extremely colourful.

To read a blog post from 2020 about the discovery of a tapejarid pterosaur in the Wessex Formation (Wightia declivirostris): A Terrific Tapejarid from the Isle of Wight.

Significantly, the recently published paper reveals evidence of something remarkable.

Scientists identified a layered arrangement of melanosomes within the pycnofibres of a tapejarid specimen. The fossil material represents Sinopterus dongi from the Early Cretaceous Jehol Biota.  It had not been formally studied previously. Importantly, this internal structure of melanosomes resembles the organisation seen in the iridescent feathers of living birds. In modern species, such arrangements generate structural colours that can shift and shimmer when viewed from different angles. Consequently, the researchers propose that these pterosaurs exhibited colours ranging from green to magenta.

Did Iridescence Appear Early in the Evolution of Integumentary Filaments?

The research also has wider implications. According to the authors, this discovery indicates that the capacity for producing iridescence evolved very early in the evolution of integumentary filaments. Therefore, complex colour signalling and visual displays may have originated long before the appearance of birds.

In addition, the research provides further evidence that pycnofibres were multifunctional. Although they probably helped with insulation and thermoregulation, they also appear to have been used for communication and display. This finding supports the idea that visual signalling played a significant role in pterosaur behaviour. After all, if you are a tapejarid with a bold crest, then why not have iridescent pycnofibres too?  The Early Cretaceous skies could have been filled with colourful tapejarid pterosaurs.

Highlighting the importance of this recent research, Mike from Everything Dinosaur commented:

“Large head crests already made tapejarids some of the most distinctive pterosaurs known. Now, scientists suggest that these reptiles may have enhanced their appearance with dazzling colours. Such displays could have helped attract mates, establish dominance or identify members of the same species.”

Implications for Palaeoartists and Model Makers

Most pterosaurs very probably had excellent colour vision.  Using colour for signalling, social status and display makes sense.  This has implications for model makers and palaeoartists. As a result of this study, colourful tapejarid pterosaurs may have looked far more vibrant than traditionally portrayed. They might have rivalled many modern birds in both appearance and visual complexity.

A model of Tapejara imperator (Safari Ltd)

The image (above) shows a model of a tapejarid pterosaur (Tapejara imperator).  Most models have bright crests, but the pycnofibres tend to be plain in comparison. The conclusions from this study suggest a re-think when it comes to pterosaur colouration.

The paper highlights how exceptionally preserved fossils continue to transform our understanding of prehistoric life. Moreover, it demonstrates that the skies of the Cretaceous Period may have been filled with flying reptiles adorned with brilliant, iridescent colours.

The scientific paper: “Iridescence in pterosaur pycnofibers and the evolution of integumentary coloration” by Zelin Wu, Liliana D’ Alba, Chang-Fu Zhou, Julia A. Clarke, Jinhua Li, Matthew D. Shawkey and Quanguo Li published in bioRxiv.

The award-winning Everything Dinosaur website: Models of Pterosaurs and Other Prehistoric Animals.

A newly published study examining the growth rates of Dimetrodon teutonis and Dimetrodon natalis has provided a fresh perspective on a famous, primitive synapsid. Researchers have discovered that the smallest known species of Dimetrodon achieved their diminutive size in contrasting ways. The study provides fresh insights into the lives of these iconic sail-backed predators that roamed the Earth millions of years before the dinosaurs evolved.

The Dimetrodon genus comprises several species. Most of these species grew into large predators more than three metres in length.  For example, Dimetrodon grandis measured about 3.2 metres long and weighed approximately 250 kilograms. However, a few species were much smaller. An international team of researchers has now investigated how these animals evolved their reduced body size.

Dimetrodon teutonis – The Smallest Known Dimetrodon Species

The study focused on two species. One is Dimetrodon natalis from North America. The other is Dimetrodon teutonis from the Bromacker fossil site in Germany. This German species is significant because it is the only known Dimetrodon discovered outside North America.

For many years, D. natalis was regarded as the smallest species. However, D. teutonis turned out to be even smaller.

• Dimetrodon natalis – named in 1936 by Romer from earlier work by Cope. It measures about 1.7 metres long with an estimated bodyweight of 38 kilograms*.
• Dimetrodon teutonis – named in 2001 (Berman, Reisz, Martens and Henrici) and measuring around 70 cm in length and weighing approximately 24 kilograms*.

Limb bone midshaft circumference analysis of fossil material used in this research suggests that the individual animals representing D. teutonis had a body weight of 6.3 to 6.8 kilograms. In contrast, the same analysis method provides body weight estimates for the D. natalis individuals between 20.9 and 21.7 kilograms.

To learn more about these animals, the scientists examined the microscopic structure of fossil bones. Bone tissue preserves information about growth rates and development. Therefore, it can reveal important details about the life history of extinct species.

Bone Histology Reveals Different Life Histories

The results have been published in the academic journal “Scientific Reports”. They show that the two species followed contrasting growth strategies. Dimetrodon natalis appears to have grown quickly. However, it stopped growing at an early age. As a result, it reached adulthood while remaining small. In contrast, Dimetrodon teutonis grew much more slowly. It continued developing over a longer period. The researchers suggest that it probably reached sexual maturity later in life.

Bone histology comparison between D. teutonis and D. natalis demonstrates fundamentally different bone microanatomy. The humerus cross section of D. teutonis (left) exhibits thin cortices composed of poorly vascularized parallel-fibered bone. This suggests slow growth and delayed maturity. In contrast, the bone histology of D. natalis (right) shows thick and highly vascularised woven to parallel-fibered bone cortices. Picture credit: Frederik Spindler, PALAEONAVIX.

Picture credit: Frederik Spindler, PALAEONAVIX

Dr Tom Hübner, curator and head of the Bromacker project at the Friedenstein Foundation Gotha, commented:

“This work demonstrates that bone histology can provide direct insights into the palaeobiology of long-extinct animals. Who would have thought that these two small species had such different life histories?”

Different Environments Influenced Growth

According to the research team, environmental conditions played a key role. North American Dimetrodon species lived in humid lowland habitats. These ecosystems contained abundant food resources. In addition, predators were common. Under these conditions, rapid growth would have offered advantages for survival and reproduction.

The Bromacker ecosystem in Germany presented different challenges. Seasonal droughts and limited resources shaped this environment. Fossilised burrows suggest that potential prey animals retreated underground during dry periods. Consequently, slower growth may have helped Dimetrodon teutonis cope with fluctuating food supplies.

Dr Aurore Canoville explained:

“These new findings once again highlight the uniqueness of the Bromacker locality compared with other Early Permian fossil sites. They make Dimetrodon even more fascinating. Long before dinosaurs dominated the Earth, these early synapsids were already responding in remarkably flexible ways to climate, food availability, competition and predation.”

Unique Insights from the Bromacker Fossil Site

Professor Jörg Fröbisch of the Museum für Naturkunde Berlin emphasised the importance of the discovery.

He stated:

“These fascinating results provide an increasingly complete picture of the Bromacker ecosystem and its enormous potential for many decades of future research.”

The study highlights how adaptable these early synapsids were. It also demonstrates the importance of the Bromacker fossil locality. Thanks to discoveries such as these, scientists continue to improve our understanding of life during the Early Permian.

Unique fossil provides information on Bromacker food web: Regurgitated Pellet from a Dimetrodon.

In the paper, the researchers state that the largest known species of Dimetrodon is D. angelensis.  It is stated that this species was up to 4.6 metres long and weighed 250 kilograms.

Everything Dinosaur acknowledges the assistance of a media release from the Museum für Naturkunde Berlin in the compilation of this article.

The scientific paper: “Contrasting life history in the diminutive Dimetrodon species from North America and Germany” by Aurore Canoville, Philipp L. Knaus, Lorenzo Marchetti and Jörg Fröbisch published in Scientific Reports.

The award-winning Everything Dinosaur website: Models of Palaeozoic Creatures and Other Prehistoric Animals.

The debate about lips in dinosaurs continues.  Whether dinosaurs possessed extraoral tissue remains controversial. However, a remarkable new study has added substantial support to the idea that most dinosaurs possessed extraoral tissues that covered and protected their teeth. A new study, published in the journal “Palaeontology” provides compelling evidence that lips were the ancestral condition in dinosaurs and many other reptiles.

Researchers led by Rafael Terras (Programa de Pós-Graduação em Ciências Ambientais, Universidade Comunitária da Região de Chapecó, Chapecó, Brazil), have examined Triassic archosaurs from Brazil. Their findings suggest that lips in dinosaurs were not an unusual feature. Instead, they may represent the ancestral condition for the entire Sauropsida, the group that includes reptiles and birds.

Importantly, this study does not stand alone. Rather, it builds upon previous work by researchers such as Robert Bakker, Thomas Paul, Casey Holliday, Mark Witton and Thomas Cullen. Consequently, the scientific case for lips in dinosaurs continues to grow.

A Debate That Goes Back More Than a Century

The idea of lips in dinosaurs is not new. In the 1920s, palaeontologist Charles Gilmore suggested that openings in the jaw of Ceratosaurus transmitted nerves and blood vessels to the lips. Later, Robert Bakker proposed that many dinosaurs possessed thin, immobile lips similar to those seen in living lizards. Ironically, the advent of cinema and the need to make dinosaurs scary by showing their teeth could have popularised non-lipped dinosaurs with the public.

More recently, the landmark 2023 study by Cullen and colleagues demonstrated that theropod teeth show little evidence of the wear expected if they had remained permanently exposed. Their work also highlighted similarities between theropod skull anatomy and living squamates.

To read more about the 2023 study: New Paper Suggests Dinosaurs Had Lips.

Now, this new study extends these observations far beyond the Theropoda.

Studying Triassic Archosauromorphs from Brazil

The researchers examined numerous Triassic archosaurs from southern Brazil. These included early dinosaurs and several crocodile-line relatives.

They found several features associated with covered teeth.  For example, the team examined the location of foramina (tiny openings in the skull bones which are location points for nerves).

The researchers identified the following, consistent characteristics:

• rows of horizontally arranged facial foramina.
• fewer than one hundred foramina per rostral bone.
• vertically orientated teeth.
• a lack of interlocking teeth.
• uniform enamel thickness.
• no evidence of exposed dentine.
• a positive relationship between skull length and tooth crown height.

These characteristics closely resemble those seen in living lizards (lepidosaurs) rather than modern crocodilians. As a result, the authors concluded that labial scales and extensive gingiva (soft tissue that supports the teeth – gums) probably enclosed the teeth.

Foramina in selected Triassic saurischians. A, Buriolestes (ULBRA PVT 280). B, Buriolestes (CAPPA/UFSM 0035). C, Pampadromaeus (ULBRA PVT 016). D, Gnathovorax (CAPPA/UFSM 0009). E, Unaysaurus (UFSM 11069). F, Macrocollum (CAPPA/UFSM 0001a). G, Gnathovorax (CAPPA/UFSM 0009). H, Macrocollum (CAPPA/UFSM 0001d). Abbreviations: edf, ellipsoid dentary foramen; emf, ellipsoid maxillary foramen; faaf, foramen anterior to the maxillary fenestra; fdaf, foramen dorsal to the antorbital fenestra; gif, groove-inserted foramen; odf, oval dentary foramen; omf, oval maxillary foramen; opmf, oval premaxillary foramen; sbg, subnarial gap; sf, subnarial foramen. Scale bars represent: 10 mm (A–C, E, H); 25 mm (D, F, G). Picture credit: Terras et al.

Picture credit: Terras et al

Tooth Histology Provides Important Clues for Lips in Dinosaurs

The researchers also examined thin sections of fossil teeth. They discovered that enamel thickness remained consistent around the crowns. Furthermore, the dentine showed no signs of wear. This condition contrasts strongly with crocodilians, whose exposed teeth experience significant abrasion. Therefore, the teeth of these Triassic archosaurs appear to have remained hydrated and protected.

This conclusion mirrors the findings published by Cullen and colleagues in the 2023 paper. Consequently, independent lines of evidence are converging on the same answer.

Studying the Pseudosuchian Prestosuchus

One of the most intriguing aspects of the study concerns the giant pseudosuchian Prestosuchus. This large, terrestrial predator possessed a distinctive gap between the upper and lower jaws. At first glance, this arrangement might suggest permanently exposed teeth. However, the researchers argue otherwise. They propose that a mandibular gap existed between the jaws. Soft tissues and gingiva would have occupied this space and maintained a complete oral seal. In effect, the teeth remained covered despite the unusual skull shape.

Prestosuchus skulls and reconstructions. A, ULBRA PVT 281 crushed skull in right lateral view. B, reconstruction of UFRGS PV 0629 T in right lateral view (mirrored) with a mandibular gap; modified from Mastrantonio et al. (2019). C–D, life reconstructions of ULBRA PVT 281: C, in right lateral view with a closed mouth displaying the oral seal; D, in frontal view with an open mouth displaying the oral rim; artwork by Matheus F. Gadelha used with permission. Scale bars represent: 300 mm (A, C, D); 100 mm (B). Picture credit: Terras et al with illustrations by Matheus F. Gadelha.

Picture credit: Terras et al with illustrations by Matheus F. Gadelha

This interpretation is significant. It demonstrates that specialised skull anatomy does not necessarily imply exposed teeth. Moreover, it suggests that lips could be retained even in large-bodied predators with unusual cranial morphology.

Prestosuchus (P. chiniquensis) is an extinct archosaur more closely related to extant crocodilians than to the Dinosauria. Size estimates vary but it could have reached a length of five metres or more. It was one of the largest Triassic pseudosuchians and an apex predator.

The Wild Safari Prehistoric World Prestosuchus model.

The image (above) shows a model of the Triassic predator Prestosuchus.  This model was introduced in 2019.  The model has exposed teeth and no extraoral tissue.  It was made prior to the recent research suggesting the presence of lips in dinosaurs and other archosaurs.  The Prestosuchus model is from the Wild Safari Prehistoric World range of figures.

Wild Safari Prehistoric World: Prehistoric Animal Models and Figures.

Lips in Specialised Archosauromorphs

The authors also considered a number of highly specialised forms. They concluded that lips probably occurred in a wide variety of archosaurs.  For example, the researchers suggest that Triassic theropods had lips, along with sauropodomorph dinosaurs.  In addition, they propose that ornithosuchids (pseudosuchian archosaurs – crocodilian lineage) had lips.  Furthermore, the researchers propose that proterosuchids (basal archosaurs) also had extraoral tissue.  It is suggested that phytosaurs had lips too. Some archosauromorphs evolved additional keratinous coverings. These structures formed primitive beaks (rhamphothecae).

Triassic archosauromorphs reconstructed with labial scales and the oral seal in lateral view. A, Gnathovorax (CAPPA/UFSM 0009; Herrerasauria). B, Pampadromaeus (ULBRA PTV 016; Sauropodomorpha). C, Machaeroprosopus (NMMNH P-4983; Phytosauria). D, Riojasuchus (PVL 3827; Ornithosuchidae). E, Proterosuchus (NMQR 880; Proterosuchidae). F, Silesaurus (ZPAL Ab III/361; Silesauridae). G, Venetoraptor (CAPPA/UFSM 0356; Lagerptidae). H, ‘Hyperodapedon’ (ULBRA PVT 053; Rhynchosauria). I, Prestosuchus (ULBRA PTV 281; Loricata). Artwork by Matheus F. Gadelha used with permission. Scale bars represent: 50 mm (A, D); 20 mm (B, F); 100 mm (C, H); 30 mm (E); 10 mm (G); 300 mm (I). Picture credit: Terras et al with illustrations by Matheus F. Gadelha.

Picture credit: Terras et al with illustrations by Matheus F. Gadelha

A Complex Picture

The evolution of facial tissues in archosaurs appears to have been far more complex than previously thought.  However, extraoral soft tissues such as lips were probably the ancestral condition. According to the authors of the study, lips represent the primitive condition for the Sauropsida. Therefore, the common ancestor of reptiles and birds likely possessed covered teeth.

If correct, exposed teeth evolved later.  Extant crocodilians would represent a more derived branch of the Archosauria. Their exposed dentition and highly sensitive facial skin appear to be derived adaptations rather than the ancestral state. This finding reverses a common assumption.  However, the debate about lips in dinosaurs and their near relatives is likely to continue.

Instead of asking why dinosaurs had lips, researchers may need to explain why crocodilians lost them.

A Growing Scientific Consensus

No single paper or study can settle such a complex question. Nevertheless, the evidence continues to accumulate. Studies of facial foramina, tooth wear, enamel thickness and skull proportions increasingly point in the same direction. Taken together, they indicate that most dinosaurs probably possessed extraoral tissues covering their teeth. As a result, reconstructions showing permanently exposed teeth may eventually become less common.

This study is significant because it suggests origins for this condition originated much earlier in archosaur evolution. Consequently, it provides fresh evidence that covered teeth were widespread among early members of the Archosauria. Furthermore, it strengthens the idea that the familiar crocodilian condition evolved later.

The head of a stuffed crocodile specimen (Nile crocodile) on display at the London Natural History Museum. The lack of extraoral tissue (lips) in this archosaur might be a derived condition. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Mike from Everything Dinosaur commented:

“This exciting new research adds another important piece to the puzzle. Evidence supporting lips in dinosaurs has been steadily accumulating for many years. The research team have shown that these soft tissues probably have much deeper evolutionary roots than previously thought. Their work strengthens the view that covered teeth represented the ancestral condition in dinosaurs and many of their close relatives. As a result, palaeoartists and scientists are gaining an increasingly detailed picture of how these remarkable animals actually looked.”

Everything Dinosaur acknowledges the assistance of the study’s corresponding author in the compilation of this article.

The scientific paper: “Inferred presence of extraoral tissues in Triassic archosauromorphs and the evolutionary implications for the clade Sauropsida” by Rafael Terras, Jaqueline Borger, Manuelle O. P. Almeida, Silvia Bettin, Owen A. Higgins, Giulia Marciani, Stefano Benazzi, Rodrigo T. Müller, Leonardo Kerber and Mirian Carbonera published in Palaeontology.

The Everything Dinosaur website: Museum Quality Models of Archosaurs.

Recently, we published a post highlighting the on-going research into the remarkable Oxfordshire “dinosaur highway”.  A limestone quarry preserves the remains of numerous dinosaur tracks.  The tracks are preserved in strata laid down in the Middle Jurassic.  Palaeontologists estimate that the trackways are around 166 million years old (Bathonian faunal stage).  In a recent radio interview, a researcher commented that one of the tracks could be a record breaker. At around 220 metres in length, one Oxfordshire trackway could represent the longest continuous sauropod trackway known to science. However, describing them as Cetiosaurus dinosaur tracks is somewhat controversial.

To read Everything Dinosaur’s earlier blog post: Oxfordshire Trackway Could be the Longest Sauropod Trackway Discovered to Date.

Could a Cetiosaurus Have Left the Longest Sauropod Trackway?

Whilst undoubtedly made by sauropods, it is difficult to assign with any certainty the taxon that walked across a lagoon that led to the footprints being trapped in time.  Indeed, as the tracks are different sizes, they could represent several taxa.  Alternatively, the tracks might represent a single species, but different aged individuals walking together.  However, Cetiosaurus is the sauropod most often mentioned in association with the trace fossils.  Why might that be the case?

An artist’s reconstruction of the Dewars Farm Quarry site 166 million years ago. A Megalosaurus tracks an adult Cetiosaurus with a second sauropod in the background whilst pterosaurs soar overhead. Picture credit: Mark Witton.

Picture credit: Mark Witton

Cetiosaurus is regarded as being a primitive member of the Sauropoda. Nevertheless, this is an important genus. It has the distinction of being regarded as the first sauropod dinosaur to be formally described (Owen 1841). However, Owen’s scientific study was inaccurate. For example, Owen suggested that the large vertebrae with their rough texture were similar to extant whale vertebrae. As the fossils had been found in marine deposits, Owen incorrectly concluded that the fossils represented an enormous marine crocodile.

Cetiosaurus oxoniensis

Unfortunately, most Cetiosaurus fossil specimens consist of fragmentary material.  Indeed, little is known about Middle Jurassic sauropods.  Significantly, the species Cetiosaurus oxoniensis was described from fossils found in Oxfordshire.  The material comes from deposits that are approximately the same age as the trackway bedding planes at the quarry site.  So, it is possible that these extensive trace fossils do indeed represent Cetiosaurus dinosaur tracks.

The enormous and robust right femur of a Middle Jurassic sauropod. The femur has been ascribed to the taxon Cetiosaurus. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Cetiosaurus Dinosaur Tracks

Whether or not these footprints represent Cetiosaurus dinosaur tracks remains open to debate.  However, as perhaps the first sauropod formally described, this taxon is iconic.  In addition, it is pleasing symmetry if a Cetiosaurus did leave what may prove to be the world’s longest sauropod trackway. Such an accolade only enriches England’s rich fossil heritage.

Mike from Everything Dinosaur commented:

“At around 220 metres in length, one Oxfordshire trackway could represent the longest continuous sauropod trackway ever discovered. Other lengthy European sauropod trackways are known.  For example, from Portugal and France.  These fossil trackways are over 140 metres in length, so they are considerably shorter than the trackway from Oxfordshire.  Nonetheless, they are still impressive and give palaeontologists the opportunity to learn more about these enormous creatures.”

Everything Dinosaur acknowledges the assistance of a media release from the University of Birmingham supplied in January 2025 in the compilation of this article.

For sauropod models and other dinosaurs: Dinosaur Figures and Prehistoric Animal Models.