Researchers at the Museum für Naturkunde Berlin (Germany) made a spectacular discovery while cataloguing their collections. A fossilised plant specimen challenges long-held perceptions about the evolutionary origins of cannabis. The potential fossil cannabis plant discovered near Eisleben in Saxony-Anhalt, could be the oldest known example of the cannabis genus.

While reviewing historical collections, scientists uncovered a fossilised leaf impression originally described in 1883. At the time, researchers named it Cannabis oligocaenica. However, new dating evidence places this specimen much earlier than previously thought.  The fossil does not date from the Oligocene Epoch.  It is much older.  Recent dating using sophisticated technology places the fossil in the Lower Eocene, approximately 56–48 million years ago.

Potential fossil cannabis plant sheds doubt on the Asian origins of the Cannabaceae. Picture credit: Ludwig Luthardt.

Picture credit: Ludwig Luthardt

A Potential Fossil Cannabis Plant

The modern cannabis species (Cannabis sativa), probably originated in north-western China.  This hypothesis is supported by the analysis of fossil pollen grains indicating the presence of these plants in China around twenty million years ago.  Today, the plant is still endemic to China.  However, molecular clock studies suggest an origin approximately twenty-eight million years ago.

The evolutionary origins of these plants, prized for their stimulant and hallucinogenic properties is challenged by this chance discovery. The fossil represents a leaf impression preserved in lithified mud, first described in 1883 and named Cannabis oligocaenica. Despite its name suggesting an Oligocene origin, the fossil is much older.

The fossil’s shape, with its serrated margins and narrow lance-shaped leaves, closely resembles modern cannabis plants. However, key diagnostic features are missing, such as the fine hairs found on living species. These hairs produce the psychoactive compound tetrahydrocannabinol (THC). It is thought plants evolved this compound to help counter the attention of grazing animals.

It remains uncertain whether this fossil specimen represents the earliest known cannabis plant.

One thing for sure, the specimen is a “high-light” of the Museum’s fossil plant collection.

Mike from Everything Dinosaur stated:

“This story demonstrates the importance of re-assessing specimens in museum collections. If confirmed, it could extend the evolutionary origins of cannabis by tens of millions of years. In addition, this fossil challenges the idea of an Asian origin for these plants.”

Visit the Everything Dinosaur website: Prehistoric Animal Models.

A reassessment of horned dinosaur fossils discovered ninety years ago in the famous Dinosaur Provincial Park Formation of Alberta has led to the erection of a new chasmosaurine species.  Previously assigned as the holotype for the species Chasmosaurus russelli, the fossil material (CMNFV 8800), has been re-described as Cryptarcus russelli.  This revision of chasmosaurine fossil material demonstrates how modern research continues to refine dinosaur classification.

Holotype skull material (formerly Chasmosaurus russelli) now assigned to Cryptarcus russelli shown in left lateral view. The restored jugal is highlighted. Picture credit: Everything Dinosaur with line drawing based on Figure 3 (part A) from the scientific paper.

Picture credit: Everything Dinosaur with line drawing based on Figure 3 (part A) from the scientific paper.

Line drawing created from Figure 3 in [Holmes et al] (2026), New information on the holotype of “Chasmosaurus” russelli (Ornithischia: Ceratopsidae) necessitates the establishment of a new genus to receive the species”, licensed under CC BY 4.0.

An Iconic Fossil Specimen is Re-defined

Discovered in 1936 and named Chasmosaurus russelli in 1940 (Sternberg), the fossil material reviewed in a study published in the Canadian Journal of Earth Sciences changes views on the evolution and radiation of the Chasmosaurinae. For decades, Chasmosaurus russelli was considered one of two species within the genus Chasmosaurus.  However, palaeontologists have long suspected that something was unusual about this specimen. While it shared traits with other Chasmosaurus fossil material, it also displayed features seen in more distantly related horned dinosaurs. This raised an important question. Did C. russelli truly belong in the Chasmosaurus genus?

To answer this question, researchers carefully re-examined the original skull. They removed old plaster reconstructions and re-prepared the fossil. This step was crucial because earlier restoration work had obscured important anatomical details.  For example, old paint was removed and a fine preparation using a mounted needle was undertaken to remove artificial surface sculpturing and restoration plaster. The jugal was identified as having been restored during the original preparation work in the late 1930s.  The holotype skull was carefully photographed and documented.

Next, the researchers conducted a detailed anatomical study. They focused on key skull features, especially the frill and facial bones. In addition, they carried out phylogenetic analyses. These tests compared the fossil’s characteristics with those of other members of the Chasmosaurinae subfamily.

The Chasmosaurus genus has proved popular with dinosaur model collectors and several Chasmosaurus figures have been made.  The image shows the two Haolonggood Chasmosaurus figures.

To view the range of Haolonggood ceratopsians and other dinosaurs available: Haolonggood Dinosaur Models.

Inconsistent Results

Interestingly, the results were inconsistent. Some analyses placed the specimen closer to Chasmosaurus. Others linked it more closely to taxa known from southern Laramidia such as Pentaceratops and Utahceratops. In some cases, its phylogenetic position could not be resolved at all.

To read our blog post from 2022 about the discovery of a new chasmosaurine dinosaur from New Mexico: New Chasmosaurine Described from Southern Laramidia.

The specimen CMNFV 8800 shows a mix of features seen in genera such as Agujaceratops, Utahceratops and Pentaceratops.  However, these traits appear in a scattered and inconsistent way, making it difficult to link the specimen closely to any one of these dinosaurs. As a result, researchers found no strong evidence to place CMNFV 8800 within an existing genus, although future discoveries could refine its position.

Importantly, some features once thought diagnostic of Chasmosaurus were found to be unreliable. For instance, traits like horn size and frill shape can vary according to ontogeny or fossil taphonomy.

Crucially, the specimen is both distinctive and clearly identifiable when compared to other chasmosaurines. For this reason, the researchers established a new genus, Cryptarcus, to accommodate the holotype previously known as Chasmosaurus russelli. Other fossils from the lower Dinosaur Park Formation that have traditionally been assigned to this species will be reassessed in a future study.

Cryptarcus russelli

As the specimen could not be confidently assigned to Chasmosaurus or any other genus, the researchers made a decisive move. They erected a new genus, Cryptarcus, to accommodate these fossils. The name Cryptarcus means “hidden arch”. It reflects both the dinosaur’s concealed identity within the Chasmosaurus genus and the distinctive arch shape of its frill.

Furthermore, the study suggests this dinosaur may represent a separate evolutionary lineage. It could be related to southern chasmosaurines like Pentaceratops. Alternatively, its features may have evolved independently through convergent evolution.  The erection of C. russelli highlights the complexity of ceratopsian evolution. Horned dinosaurs often display subtle differences in their skulls. These differences can be difficult to interpret, especially when fossils are incomplete or distorted.

As a result, taxonomic revisions to the Ceratopsidae are not uncommon. They show how new techniques and re-examining previously described material can reveal hidden diversity within well-known dinosaur groups. The naming of Cryptarcus russelli marks an important step in ceratopsian research. By revisiting an old fossil with new methods, scientists have uncovered a new genus hiding in plain sight.

This discovery reminds us that even familiar dinosaurs can still surprise us. Moreover, it shows that previous assumptions about the fauna associated with the Dinosaur Park Formation might be incorrect.

Research from 2020 linking chasmosaurines from southern Laramidia to chasmosaurines from Alberta: Two New Transitional Chasmosaurine Dinosaurs.

The scientific paper: “New information on the holotype of “Chasmosaurus” russelli (Ornithischia: Ceratopsidae) necessitates the establishment of a new genus to receive the species” by Robert B. Holmes, Jordan C. Mallon, Michael J. Ryan and David C. Evans published in the Canadian Journal of Earth Sciences.

Researchers have described a new species of duck-billed dinosaur from fragmentary fossils found in Jiangxi Province, China.  The hadrosaur has been named Gongshuilong fanwei.

In the early spring of 2021 construction workers uncovered fossils from exposures of the Upper Cretaceous Lianhe Formation. The exposures date from the very end of the Cretaceous (Maastrichtian faunal stage). The fragmentary remains of a least two individuals were identified. Intriguingly, the neural spines of the caudal vertebrae are elongated. Some of these neural spines are eight and half times the height of their centrum. It is likely that these tail bones supported a fan-like tail. Such an exaggerated, fan-like tail has not been found in any related hadrosaurs.

A life reconstruction of the newly described saurolophine hadrosaur Gongshuilong fanwei from China. This duck-billed dinosaur is estimated to have reached a body length of around 7 metres. Picture credit: Everything Dinosaur (AI assisted).

Picture credit: Everything Dinosaur (AI assisted)

Gongshuilong fanwei

A phylogenetic analysis indicates that Gongshuilong is a member of the Saurolophinae subfamily.  Specifically, it has been classified as a member of the Brachylophosaurini.  As such, it is only the second member of this tribe to have been discovered in Asia. Furthermore, Gongshuilong is the first scientifically described hadrosaurid genus from South China.

A phylogenetic analysis indicates that Gongshuilong is a member of the Saurolophinae subfamily.  Specifically, it has been classified as a member of the Brachylophosaurini.  As such, it is only the second member of this tribe to have been discovered in Asia. Furthermore, Gongshuilong is the first scientifically described hadrosaurid genus from South China.  The genus name translates as “Gong River dragon”, a reference to the dig site being close to the Gong River.

The discovery of this new hadrosaur adds to the growing diversity of duck-billed dinosaurs known from the Late Cretaceous of Asia. Intriguingly, the authors of the study postulate that Gongshuilong increases the possibility of an Asian origin for the Saurolophinae and Brachylophosaurini.

The scientific paper: “A new saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the Upper Cretaceous of South China, providing further support for the possible Asian origin of Brachylophosaurini” by Han Yao, Wenjiang Qiu, Juan Yu, Ling Yang, Huimin Wang, Shenghua Cao, Kui Zhao, Mengyuan Xu, Guo Shi, Fasheng Lou, Cuimin Zeng, Pikun Lu, Rui Wu, Xing Xu, Fenglu Han and Hai Xing published in the Journal of Systematic Palaeontology.

Visit the Everything Dinosaur website: Dinosaur Models.

A recently published scientific paper has revealed the discovery of a new Chinese sauropodomorph. The new species, Xiangyunloong fengming, helps fill an important gap in our understanding of early sauropodomorph diversity. The fossils of Xiangyunloong fengming were discovered in the Lower Jurassic Fengjiahe Formation. This site is located in Luming Town, Xiangyun County, Yunnan Province.

Importantly, this locality lies around 125 miles (200 kilometres) west of the famous Lufeng fossil beds. Although the Lufeng Formation has produced abundant fossils, including sauropodomorphs such as Lufengosaurus, Jingshanosaurus, and Yunnanosaurus, other Lower Jurassic deposits of the same geological age remain comparatively underexplored.

Xiangyunloong fengming

This dinosaur is described from a partial skeleton that includes cervical, dorsal and caudal vertebrae, fragments of dorsal ribs, chevrons, part of the left ilium and a right ischium. Although incomplete, the remains preserve enough detail to identify a new dinosaur taxon. Several unique autapomorphies were identified.  For example, the neck vertebrae show unusual lateral expansions.  In addition, the ilium displays a distinctive flared crest. This suggests differences in muscle attachment and locomotion.

The robust nature of the hip bones suggests that Xiangyunloong fengming was a relatively large animal, likely comparable in size to some of the bigger Early Jurassic sauropodomorphs. It has been speculated that this dinosaur could have been around 9-10 metres long.

At around 9-10 metres in length Xiangyunloong is much larger than the coeval Lufengosaurus. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Phylogenetic analysis indicates that Xiangyunloong may represent a transitional form between the Massospondylidae and more derived sauropodiform dinosaurs.

Expanding Early Jurassic Dinosaur Diversity

This discovery highlights the diversity of early sauropodomorphs in China. Previously, most fossils came from a limited number of locations. Now, Xiangyunloong fengming demonstrates that these dinosaurs were more widespread than previously thought. Consequently, this find improves our understanding of their distribution.

Moreover, it suggests that regional ecosystems may have supported a wider variety of species. This has important implications for Early Jurassic palaeoecology.

The name Xiangyunloong translates to “auspicious cloud dragon”. It references the name of the county where the fossils were found.  In addition, it incorporates the traditional term for dragon.  The species name honours Lin Fengmian, the artistic master and founding president of the China Academy of Art, whose staff participated in the excavation and preparation of the fossil material.  Furthermore, the species name translates as “phoenix calling”.  It is a reference to Luming (deer calling), a town close to the fossil quarry.  The species name reminds us that birds are living dinosaurs. Hence the dinosaur’s name symbolises both the locality and the evolutionary link between dinosaurs and birds.

The Significance of Xiangyunloong fengming

In summary, Xiangyunloong fengming provides new insight into early dinosaur evolution. It fills a geographic gap and adds to the growing diversity of known sauropodomorphs.

Furthermore, its mix of primitive and derived features makes it especially important. It helps bridge the gap between early forms and later giants. The large body size, proportionally short cervical vertebrae and the robust hip bones indicate an initial stage of gigantism and a potential bipedal locomotion. This may represent an alternative evolutionary pathway to the neck elongation seen in other early-diverging sauropodomorphs.

As a result, this discovery represents another step forward in understanding how some of the largest animals to ever walk the Earth evolved.

The scientific paper “A new sauropodomorph dinosaur from the Lower Jurassic Fengjiahe Formation of Dali of Yunnan Province, China” by Shao-Bin Hu, Yan-Chao Wang, Xiong Mo, Xiao-Qin Zhang, Wen-Tao Zeng, Tao Wang, Zai-Bo Sun, Qi-Xing Dong, Qi Guan, Yi-Hong Liu, Yu-Shen Zhang, Yin Bing, Ya-Ming Wang and Hai-Lu You published by The Royal Society Open Science.

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

Phytosaurs might look like modern crocodiles, but they are different.  They fill the same ecological niches in ecosystems, however, the extinct phytosaurs only resemble modern crocodilians superficially.  The nostril position for example. In phytosaurs, due to the extended premaxillae the nostrils are located much closer to the eyes.  In addition, the layout of the manus and pedes is different.

The Phytosaur Pes

In phytosaurs, the fourth digit of the foot (IV) tends to be the largest. In contrast, digit V (the fifth digit) is much reduced, although it still possessed a claw. From what we can see, the new CollectA Colossosuchus phytosaur model has anatomically accurate hind feet. Overall, it seems quite an accurate representation of a mystriosuchine phytosaur,

The phytosaur pedes – a helpful guide. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

To view the range of CollectA figures in stock at Everything Dinosaur: CollectA Prehistoric Life Figures.

Remember, the singular is pes, when discussing both hind feet the plural is used – pedes.

The Phytosaur Manus

To the best of our knowledge the manus (hand) of phytosaurs has the following digit formula (right manus).

In a right manus (forelimb/hand) of a typical phytosaur:

• Digit I (pollex) is located on the medial side, nearest to the body’s midline.
• Digit V is the lateral-most digit, located farthest from the midline.

The implications for phytosaur models are significant. When reconstructing a right manus, if viewed from the dorsal (top) side, the correct digit arrangement (from medial to lateral) is:

I → II → III → IV → V

This means:

Digit I is the “thumb” side.

Digit V is the “little finger” side.

If the manus is oriented palm-down (pronated), the pollex (digit I) points toward the midline of the animal.  The CollectA Colossosuchus manus has five digits.  They all seem in proportion, although I am not sure whether the outermost digit (V) had a claw.  In the CollectA phytosaur model, digit V is much reduced, and it has a tiny claw.

Mike from Everything Dinosaur commented:

“Although bones from the pedes and manus are known in the Phytosauria fossil record, they are rare.  However, palaeontologists have been able to use trackways assigned to phytosaurs to work out the anatomy.”

The Everything Dinosaur website: Prehistoric Animal Models.

A remarkable new dinosaur discovery from South Korea has captured both scientific and public attention. Researchers have named a newly identified species Doolysaurus huhmini, inspired by a famous cartoon character loved across generations.

A Dinosaur Inspired by a Cultural Icon

The name Doolysaurus honours “Dooly”, a mischievous green cartoon dinosaur well known in South Korea. As a result, the name creates a meaningful link between science and popular culture. Lead researcher Jongyun Jung explained that the connection felt natural. The fossil represents a young individual, and the cartoon character is also depicted as a baby dinosaur. Therefore, the name is both scientifically appropriate and culturally significant.

A life reconstruction of a juvenile Doolysaurus huhmini. It is depicted alongside birds and other dinosaurs that lived during the Cretaceous in what is now South Korea. Picture credit: Jun Seong Yi.

Picture credit: Jun Seong Yi

Hidden Doolysaurus huhmini Fossil Revealed by Advanced Scanning

The fossil was discovered on Aphae Island and initially appeared quite limited. Only a few leg bones and vertebrae were visible. However, everything changed once researchers used advanced micro-CT scanning technology. This technique, developed at University of Texas High-Resolution X-ray Computed Tomography Facility, allowed scientists to look inside the rock without damaging it. As a result, previously hidden skull bones and additional skeletal elements were revealed.

Importantly, this marks the first dinosaur fossil from Korea to preserve parts of the skull. Moreover, it is the first dinosaur species based on skeletal remains described from South Korea since Koreanosaurus boseongensis was named and described in 2011.

A Young Dinosaur About the Size of a Turkey

The specimen represents a juvenile dinosaur, estimated to be around two years old when it died. It measured roughly the size of a turkey. However, adults may have grown to twice that size.

Scientists identified growth markers in the femur, which confirmed its young age. In addition, the anatomy suggests that this dinosaur belonged to a group called thescelosaurids. These were small, bipedal herbivorous or omnivorous dinosaurs. Interestingly, researchers think Doolysaurus may have had a coat of fuzzy filaments. Consequently, it might have looked quite different from traditional scaly dinosaur depictions.

Study co-authors Minguk Kim (left) and Hyemin Jo during the initial discovery and excavation of Doolysaurus. Picture credit: Jongyun Jung, The University of Texas at Austin.

Picture credit: Jongyun Jung, The University of Texas at Austin

Evidence of Diet Preserved in the Fossil

The fossil also contained numerous gastroliths. These are small stones swallowed by animals to aid digestion. Their presence provides important clues to the animal’s diet. It suggests that Doolysaurus was likely an omnivore. In other words, it probably ate plants, small animals, and invertebrates. Furthermore, the gastroliths helped researchers realise that more of the skeleton might be preserved inside the rock. This insight ultimately led to the decision to scan the specimen.

The research, published in the journal Fossil Record, highlights the growing importance of CT scanning in palaeontology. This method is especially useful for small and delicate fossils. South Korea is already famous for dinosaur footprints, nests, and eggs. However, body fossils are comparatively rare. Therefore, this discovery is particularly significant.

To read Everything Dinosaur’s blog post about the discovery of fossils of an early ceratopsid dinosaur in South Korea: Koreaceratops – A Ceratopsian with a Broad Tail.

The researchers are optimistic. They believe that more hidden fossils may be waiting to be revealed using similar techniques.

The skeletal anatomy of a juvenile Doolysaurus huhmini. The graphic highlights the fossil bones that were found with the dinosaur. Known fossil bones shown in white in the skeletal drawing. Artwork: Janet Cañamar, adapted from Jung et al 2026.

Artwork: Janet Cañamar, adapted from Jung et al 2026

Looking Ahead to Future Discoveries

The team plans further fieldwork on Aphae Island and nearby locations. They hope to uncover additional specimens and expand our understanding of Korea’s prehistoric ecosystems.

As a result, Doolysaurus may be just the beginning. With continued exploration and new technology, many more discoveries could follow.

The newly discovered dinosaur species is named after the popular South Korean cartoon Dooly the Little Dinosaur. The titular Dooly is on the left. Picture credit: ⓒDoolynara.

Picture credit: ⓒDoolynara

Mike from Everything Dinosaur commented:

“This charmingly named dinosaur combines cutting-edge science with cultural storytelling. It also demonstrates how modern technology is transforming palaeontology. Most importantly, it reminds us that even well-studied regions can still yield exciting new dinosaur discoveries.”

Everything Dinosaur acknowledges the assistance of a media release from the University of Texas at Austin in the compilation of this article.

The scientific paper: “A new dinosaur species from Korea and its implications for early-diverging neornithischian diversity” by Jongyun Jung, Minguk Kim, Hyemin Jo and Julia A. Clarke published in the Fossil Record.

The award-winning Everything Dinosaur website: Dinosaur and Prehistoric Animal Models.

Oviraptorosaurs were not just unusual theropod dinosaurs. They were also closely related to true birds, sharing a common evolutionary heritage within the Maniraptora clade. As a result, many of their behaviours provide important clues about how modern avian reproduction evolved. A fascinating new study on oviraptorosaurian incubation has been published in the journal “Frontiers in Ecology and Evolution”.  The research outlines how these extremely bird-like theropods brooded their eggs. Moreover, it challenges long-held assumptions about how efficiently they incubated their clutches.

An Oviraptor and its nest.  Palaeontologists study oviraptorosaurian dinosaurs to better understand the evolutionary roots of bird-specific reproductive characteristics. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Previous studies have highlighted this close avian relationship. In particular, palaeontologists have noted that some bird-specific reproductive traits may have deeper evolutionary roots. One such trait is thermoregulatory contact incubation (TCI). This behaviour, seen in modern birds, involves direct body contact between the adult and the eggs to regulate temperature.

The study focused on the Chinese oviraptorosaurian Heyuannia huangi.

To read an earlier study that examined the colouration of oviraptorosaurian eggs: Dinosaurs May Have Laid Coloured Eggs.

Thermoregulatory Contact Incubation (TCI)

Fossil evidence strongly supports this connection. Several oviraptorid specimens have been discovered preserved on top of their nests. Strikingly, these individuals adopt postures that closely resemble avian brooding behaviour. Their forelimbs are spread over the clutch, much like a bird sheltering its eggs.  Therefore, it has been proposed that oviraptorosaurs may have undertaken a form of contact incubation similar to that of modern birds. However, as this new study demonstrates, the reality was likely more complex.

Scale drawing of the oviraptorosaurian Oviraptor philoceratops. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Specifically, the study explores how nest structure, egg arrangement, and body contact influenced embryo development. As a result, it paints a more complex picture of dinosaur reproduction than previously thought. For example, this new research reveals an important limitation. The scientists found that adult oviraptorosaurs likely could not directly warm all their eggs. Their nests typically consisted of multiple concentric rings of eggs. While the adult could cover the outer ring, the inner eggs remained partially insulated from body heat. Consequently, incubation efficiency was estimated at only around 65%, significantly lower than that seen in most modern birds.

Because of this limitation, the researchers propose a hybrid incubation strategy. In other words, oviraptorosaurs likely relied on both body heat and environmental warmth.

For example, sunlight may have warmed exposed portions of the nest. At the same time, partially buried eggs could retain heat from the surrounding sediment. Therefore, incubation was not solely dependent on the parent’s body temperature.

A Transitional Evolutionary Strategy

This mixed approach resembles strategies seen in some modern reptiles and ground-nesting birds. However, it also suggests a unique evolutionary stage between reptilian and fully avian reproduction. One key implication of this nesting strategy involves temperature variation within the clutch. Because inner and outer eggs received different amounts of heat, they likely developed at different rates. As a result, asynchronous hatching may have occurred. This means some chicks hatched earlier than others within the same nest.

In modern ecosystems, asynchronous hatching can influence survival. For instance, earlier hatchlings may gain a size advantage. However, in oviraptorosaurs, the exact biological impact remains uncertain.

Nevertheless, this study highlights how even subtle differences in nest structure could shape reproductive success.

Oviraptorosaurian Incubation and the Implications for Sex Determination

An especially intriguing section of the paper (4.3.5) examines the oviraptorid sex determination system. In modern birds, sex is determined genetically using Z and W chromosomes. Temperature does not influence whether an embryo becomes male or female. By contrast, many reptiles exhibit temperature-dependent sex determination (TSD), where incubation temperature plays a crucial role.

So, how does oviraptorosaurian incubation influence sex? The research team discusses the possibility that oviraptorids retained a genetic sex determination system, similar to birds. However, the authors also consider whether temperature variation within nests could still have influenced development in subtle ways. Importantly, there is no direct evidence that oviraptorosaurs used TSD like crocodilians or turtles. That said, the uneven incubation conditions identified in this study raise interesting questions.

For example, if temperature gradients existed across the nest, could they have affected growth rates, hatch timing, or even sex ratios? At present, this remains speculative.

Therefore, the safest conclusion is that oviraptorosaurs were likely genetically sex-determined, but their complex nesting environments may still have had biological consequences.

Combining Avian and Reptilian Traits When it Comes to Oviraptorosaurian Incubation

The researchers postulate that oviraptorosaurians occupied an evolutionary middle ground. They displayed clear bird-like behaviours, such as brooding posture and nest care. Yet, their incubation system was not as efficient as that of modern birds.

Instead, they appear to have combined avian and reptilian traits. On the one hand, they guarded and brooded their nests. On the other, they relied partly on environmental heat. Consequently, oviraptorosaurs provide a valuable window into the evolution of reproductive strategies among theropod dinosaurs.

Conclusions

This new study adds an important layer of detail to our understanding of dinosaur reproduction. It shows that brooding behaviour alone does not guarantee efficient incubation. More importantly, it highlights how nest design, temperature variation, and developmental biology all interact. Together, these factors shaped the survival of the next generation.

As more research emerges, we can expect even deeper insights into how these remarkable dinosaurs lived and reproduced.

The scientific paper: “Heat transfer in a realistic clutch reveals a lower efficiency in incubation of oviraptorid dinosaurs than of modern birds” by Chun-Yu Su, Jun-Yang Liao, Hsiao-Jou Wu, Kuan-Yu Chou, Ching Chen, Ming-Tsang Lee and Tzu-Ruei Yang published in Frontiers in Ecology and Evolution.

The multi-award-winning Everything Dinosaur website: Oviraptorosaurian and Other Dinosaur Models.

A single fossilised bone can change everything. In this case, it might reshape the story of the most famous dinosaur of all time — Tyrannosaurus rex. A new study published in the journal “Scientific Reports” describes a massive tyrannosaur leg bone discovered in New Mexico. At first glance, it looks like just another theropod fossil. However, the implications run much deeper. Researchers report the discovery of a giant fossil tyrannosaur tibia.

The Hunter Wash tyrannosaurid left tibia (NMMNH P-25085) in A, anterior, B, posterior, C, lateral, and D, medial views. Abbreviations: as, astragalus; cc, cnemial crest; fc, fibular crest; fi, fibular facet; lc, lateral condyle; mc, medial condyle. Picture credit: Nicholas R. Longrich et al.

Picture credit: Nicholas R. Longrich et al (Scientific Reports) – Open Access Paper – Creative Commons Attribution 4.0 International License

A Giant Fossil Tyrannosaur Tibia from 74 Million Years Ago

The fossil comes from the Kirtland Formation in New Mexico. It dates to around seventy-four million years ago, (Campanian faunal stage of the Late Cretaceous).  The paper’s authors are from the New Mexico Museum of Natural History and Science (Albuquerque), Montana State University and the University of Bath. They identified a tibia (lower leg bone), it measures nearly a metre in length (96 cm long and 12.8 cm in diameter).  It is a massive tibia, 84% and 78% the dimensions of the largest known Tyrannosaurus tibia. The scientists propose the existence of a five-tonne predator, an animal that would have been far larger than contemporary tyrannosaurs.  This suggests that giant tyrannosaurs evolved earlier than previously thought.

Which Taxon?

The research team compared the fossil leg bone to a large dataset of tyrannosaur anatomy. They analysed over five hundred traits to determine its evolutionary position. Their conclusion is striking. This animal likely belongs to the tribe Tyrannosaurini — the lineage that includes the famous Tyrannosaurus rex.

The fossil from the Hunter Wash Member of the Kirtland Formation (New Mexico) could represent:

• A giant specimen of the tyrannosaur Bistahieversor sealeyi.
• A previously unknown lineage of giant tyrannosaur.
• Or an early representative of the Tyrannosaurini.

Introduced in 2014, a model of the tyrannosaur from southern Laramidia (New Mexico) – Bistahieversor sealeyi.

The image (above) shows a model of the tyrannosaur Bistahieversor (B. sealeyi) from CollectA.

To view the range of not-to-scale CollectA figures in stock: CollectA Prehistoric Life Figures.

The Geographic Origins of Tyrannosaurus

The appearance of a large, derived tyrannosaurine in the late Campanian of the American Southwest also has implications for the geographic origin of Tyrannosaurus. Palaeontologists have debated where the lineage that led to T. rex evolved. Some argued for an Asian origin. Others pointed to North America. However, any theory proposed now needs to consider the presence of large tyrannosaurs in southern Laramidia.

The massive tyrannosaur tibia highlights the differences between the faunas of northern and southern Laramidia.  For example, in those geological formations representing northern Laramidia, slightly smaller tyrannosaurs are found – Gorgosaurus, Daspletosaurus and Teratophoneus. Meanwhile, larger tyrannosaurs may have been present in the southern part of this landmass.

Intriguingly, the Hunter Wash Member hints at previously unrecognized diversity among southern tyrannosaurs, with Bistahieversor coexisting with a larger and more robust tyrannosaur species represented by this fossil tibia. A small tyrannosaur, (specimen number NMMNH P-27469), has previously been identified as a juvenile of Bistahieversor. However, it shows features seen in Nanotyrannus. Therefore, a much smaller, gracile form of tyrannosaur similar to Nanotyrannus could have been coeval with Bistahieversor and a much larger tyrannosaur.

To read Everything Dinosaur’s blog post about confirmation of the Nanotyrannus taxon: Nanotyrannus – A New Chapter in Tyrannosaur Evolution.

The scientific paper: “A large tyrannosaurid from the Late Cretaceous (Campanian) of North America” by Nicholas R. Longrich, Sebastian Dalman, Spencer G. Lucas and Anthony R. Fiorillo published in Scientific Reports.

The award-winning Everything Dinosaur website: Prehistoric Animal Toys and Models.