One of the most famous museum exhibits in the world, “Sue” the enormous T. rex mount located at the Field Museum in Chicago has something new to keep her company. A life-size replica of the skeleton has been installed and museum visitors can get to see “Sue” in the flesh. The 13 metre-long life-size model was created by the amazing talented people at Blue Rhino Studio (based in Minnesota).
Staff at Blue Rhino Studio Pose Next to the Completed Tyrannosaurus rex Replica
Staff at Blue Rhino Studio photographed next to their life-size replica of Tyrannosaurus rex.
Picture credit: Blue Rhino Studio
Say Hello to “Fleshy”
The beautifully crafted replica is currently on display at the Field Museum, but is due to go shortly on a nationwide tour. The huge theropod figure is based on the skeleton of “Sue”, it shows some of the pathology associated with the fossil specimen. For example, there is a substantial scar just above the left ankle. This was the site of a bone infection, probably resulting from an injury that “Sue” had sometime during her long life. This amazing replica has been named “Fleshy”.
Blue Rhino Studio Staff Working on the Huge T. rex Replica
Blue Rhino staff working on the huge model.
Picture credit: Blue Rhino Studio
A Close-up View of the Area Above the Left Ankle Showing the Scar
A close-up view of the area above the left ankle showing the scar. The red arrow points to the patholoy on the replica.
Picture credit: Blue Rhino Studio with additional annotation by Everything Dinosaur
Tyrannosaurus rex Sharing a Home with a Titanosaur
The fossilised remains of perhaps the most famous dinosaur in North America were moved in the winter of 2018 to a new location at the museum. “Sue” can now be found within the museum’s Griffin Halls of Evolving Planet, alongside a skeleton of a titanosaur (nicknamed Máximo). The replica stands nearly 4.5 metres tall and it has a juvenile Edmontosaurus in its mouth. It is likely that E. annectens was on the menu for this Late Cretaceous apex predator.
The Life-size “Sue” T. rex Replica has a Baby Edmontosaurus in its Mouth
Team members working on the giant T. rex figure – complete with juvenile Edmontosaurus.
Picture credit: Blue Rhino Studio
The figure took two whole days to set up in the Field Museum, the staff responsible for the set build and dismantling of “Sue” hope to reduce this to just a day when the figure is on tour.
A spokesperson from Everything Dinosaur commented:
“This is an amazing piece of work! Yes, you can debate the lack of feathers, but this wonderful exhibit will really help visitors to appreciate just how large Tyrannosaurus rex actually was.”
Bone Cancer (Osteosarcoma) Identified in Dinosaur Fibula
Scientists have identified a rare malignant cancer in the fossilised bone of a horned dinosaur. Writing in “The Lancet Oncology”, the researchers report on the discovery and diagnosis of an osteosarcoma in the lower leg bone (fibula), of a Centrosaurus (Centrosaurus apertus). This is the first time that an osteosarcoma has been found in the fossilised bones of a dinosaur.
An Osteosarcoma Identified in the Leg Bone of a Dinosaur (Centrosaurus apertus)
Malignant cancer identified in horned dinosaur leg bone.
Picture credit: Royal Ontario Museum
What is an Osteosarcoma?
Osteosarcoma is a cancer that produces immature bone. There are an estimated 3.4 million cases reported in the human population each year. It mostly occurs in young people, under the age of 25 and there is some evidence to suggest that it is more prevalent in males. In our species, osteosarcoma is associated with periods of rapid bone growth, to date the cause, genetic alterations, oncogenic events and evolutionary history of osteosarcoma are poorly understood.
The research team included scientists from the Royal Ontario Museum, McMaster University (Ontario) and the Okayama University of Science (Japan), along with numerous other specialists in pathology, molecular medicine, image resonance and oncology. They subjected the leg bone to high-resolution computed tomography (CT) scans. Thin sections were than prepared and examined under a microscope to assess the specimen at the bone-cellular level. The investigators were able to reach a diagnosis of osteosarcoma, the first time such a diagnosis has been identified in a member of the Dinosauria.
Centrosaurus Life Reconstruction
Centrosaurus life reconstruction.
Picture credit: Michael W. Skrepnick
Originally Believed to be a Healing Fracture in the Centrosaurus Bone
The Centrosaurus bone was found in 1989 in the Dinosaur Provincial Park (Alberta). The badly malformed bone was thought to represent a healing fracture but it was decided to investigate its unusual morphology in order to better understand the pathology.
A Cast of the Deformed Bone (Fibula) of Centrosaurus
Evidence of a malignant tumour in a dinosaur bone. A cast of the dinosaur bone showing the deformity
One of the co-authors of the paper, Rhianne Crowther (Trent University, Ontario), commented:
“Diagnosis of aggressive cancer like this in dinosaurs has been elusive and requires medical expertise and multiple levels of analysis to properly identify. Here, we show the unmistakable signature of advanced bone cancer in 76-million-year-old horned dinosaur — the first of its kind. It’s very exciting.”
Confirming the Diagnosis, Human Compared to a Dinosaur
To confirm the diagnosis of osteosarcoma, the bone was compared to a normal fibula from a Centrosaurus. It was then compared to a human fibula with a confirmed case of osteosarcoma. The Centrosaurus was an adult dinosaur and the cancer was at an advanced stage, suggesting that it probably invaded other organs and parts of its body. The bone comes from an extensive monodominant Centrosaurus bonebed, so this dinosaur probably died with a large number of other animals in its herd during a catastrophic flood.
David Evans, a palaeontologist at the Royal Ontario Museum added:
“The shin bone shows aggressive cancer at an advanced stage. The cancer would have had crippling effects on the individual and made it very vulnerable to the formidable tyrannosaur predators of the time. The fact that this plant-eating dinosaur lived in a large, protective herd may have allowed it to survive longer than it normally would have with such a devastating disease.”
Seper Ekhtiari, an Orthopaedic Surgery Resident at McMaster University, who had also been involved in this study, stated:
“It is both fascinating and inspiring to see a similar multidisciplinary effort that we use in diagnosing and treating osteosarcoma in our patients leading to the first diagnosis of osteosarcoma in a dinosaur. This discovery reminds us of the common biological links throughout the animal kingdom and reinforces the theory that osteosarcoma tends to affect bones when and where they are growing most rapidly.”
It is hoped that this research will establish a new standard for the diagnosis of unclear pathology in vertebrate fossils. Forging links between pathology preserved in fossilised bones and human medicine will help scientists to gain a better understanding of the evolution and genetics of various diseases.
Everything Dinosaur acknowledges the assistance of a media release from the Royal Ontario Museum in the compilation of this article.
The scientific paper: “First case of osteosarcoma in a dinosaur: a multimodal diagnosis” by Seper Ekhtiari, Kentaro Chiba, Snezana Popovic, Rhianne Crowther, Gregory Wohl, Andy Kin On Wong, Darren H Tanke, Danielle M Dufault, Olivia D Geen, Naveen Parasu, Mark A Crowther and David C Evans published in The Lancet Oncology.
Jurassic Fossils from the Isle of Skye Globally Significant
The filming might have resumed for the next instalment in the “Jurassic Park/World” franchise last week, but in the scientific community there has been an important development in the study and protection of Scotland’s very own “Jurassic Park”.
Significant Jurassic Fossils
Scientists from the University of Oxford, University College London, Birmingham University the University of Edinburgh and the National Museum of Scotland have published a new scientific paper that emphasises the importance of vertebrate fossils from the Isle of Skye.
The Isle of Skye is Heralded as One of the Most Important Places in the World for Middle Jurassic Vertebrate Fossils
The Isle of Skye (Bathonian faunal stage). A newly published scientific paper heralds the vertebrate fossils from the Kilmaluag Formation on the Isle of Skye as “globally significant”.
Picture credit: Jon Hoad
The Kilmaluag Formation
Outcrops of the Bathonian-aged Kilmaluag Formation on the Trotternish peninsula on the Isle of Skye hold vital information on how vertebrate life was evolving and changing around 167 million years ago. The strata contain both body and trace fossils of numerous tetrapods including dinosaurs. Since there are not that many highly fossiliferous sites around the world providing evidence of terrestrial ecosystems and biota from back in the Middle Jurassic, the Isle of Skye has long been recognised as a hugely significant.
The area was given greater legal protection last year, when the Scottish Government signed a Nature Conservation Order (NCO), to assist in the protection of the rare vertebrate fossils found in the area and to deter irresponsible fossil collecting on the island.
In this new study, the researchers which include Scottish palaeontologist Elsa Panciroli, a research assistant in the department of Evolution and Palaeobiology at the University of Oxford, conclude that unlike other contemporaneous fossil localities from England, the strata of the Kilmaluag Formation provides partial skeletons, providing unprecedented insights and new data.
An Abundant Assemblage of Jurassic Fossils
The research team state that this location has yielded predominantly small-bodied tetrapods including amphibians, many types of reptiles (including pterosaurs and dinosaurs) and non-mammalian cynodonts as well as early mammals. An abundant fossil fish and invertebrate assemblage is also reported.
A Sauropod Track from the Isle of Skye
Sauropod track from the Isle of Skye. The Trotternish peninsula provides both body and trace fossils, such as this sauropod track for example.
Picture credit: Jon Hoad
The researchers provide a comprehensive overview of the Kilmaluag Formation, outlining the importance of its geology and the fossil discoveries made to date. They also present evidence of several species that are being reported from the Isle of Skye for the first time. The review places the vertebrate faunal assemblage in an international context and confirms the global significance of the region.
Insights into Early Mammal Evolution
Although the dinosaurs grab all the headlines, the Kilmaluag Formation is most likely to provide important information with regards to the evolutionary history of early mammals, the Squamata (lizards and snakes) along with amphibians.
The scientific paper: “Diverse vertebrate assemblage of the Kilmaluag Formation (Bathonian, Middle Jurassic) of Skye, Scotland” by Elsa Panciroli, Roger B. J. Benson, Stig Walsh, Richard J. Butler, Tiago Andrade Castro, Marc E. H. Jones and Susan E. Evans published by The Royal Society of Edinburgh/Cambridge University Press.
The global coronavirus pandemic (COVID-19) has touched the lives of nearly everyone on the planet. The measures in place to help restrict the spread of this highly infectious and pernicious disease have had a profound effect. As some restrictions are lifted, one area of science is trying to get back to near normal working practices. Fieldwork for a number of institutions and universities is beginning to commence once again, although with strict hygiene and social distancing measures in place.
Research Projects Commencing Around the World
Fieldwork has commenced as scientists in the Northern Hemisphere hope to make the best of the summer weather. However, great care will have to be taken with regards to personal hygiene and social distancing. Close proximity working as seen here, is going to have to be re-visited and many dig sites and workstations will need to be reorganised.
Scientists, like many in the rest of the population have got used to remote conference calls, webinars, Facebook discussion groups and Zoom calls. Fieldwork will still have to be carried out and in many cases, fossils exposed on the surface, if they are not collected quite quickly, can soon be eroded away once exposed to the elements.
Field teams exploring fossil sites in the Northern Hemisphere hope to make the best of the warm summer weather. Great care will have to be taken with regards to social distancing and personal hygiene. Occupying adjacent workstations at a dig site, will have to be carefully considered, as will the need to share tools, water bottles, tents and such like. Organising fieldwork involves a great deal of planning. Under the current difficulties, these plans are going to have to be even more comprehensive.
Organising Fieldwork is Going to be Even More Challenging
University of Wales Trinity Saint David (UWTSD) – Lampeter campus working at the Neolithic dig site. Fieldwork is going to have to be carefully managed under COVID-19 restrictions.
Picture credit: University of Wales Trinity Saint David (UWTSD)
A spokesperson from Everything Dinosaur commented:
“Having carefully reviewed the current guidelines, we have reluctantly cancelled all our planned fieldwork operations for the rest of this year. This has been a tough decision to make, but in the interests of all the staff and the wider community, we felt it was the right thing to do.”
We wish all those academics, commercial fossil hunters, students and volunteers about to embark on fieldwork, every success with their endeavours. Stay safe, keep well.
A comprehensive review of the fossil material associated with the Early Jurassic crested theropod Dilophosaurus (D. wetherilli) has been published. The consequences of this newly published paper for manufacturers of dinosaur models are profound. It is likely that our view of “double crested lizard” will change and with the writing of this paper, all the Dilophosaurus figures and replicas are very probably all wrong!
It’s time to “beef up” Dilophosaurus and to stop depicting it as a lightly built, gracile, weak-jawed scavenger but to recognise that this dinosaur was an apex predator!
Everything Dinosaur team members have produced a short YouTube video that explains what has happened.
Time to “Beef Up” Dilophosaurus (D. wetherilli)
Video credit: Everything Dinosaur
All Dilophosaurus wetherilli Dinosaur Models May be Wrong!
An analysis of the five most-complete Dilophosaurus specimens reveals that Dilophosaurus had stronger jaws than previously thought. That distinctive notch between the premaxilla and the maxilla (the upper jaw bones), which is so carefully depicted in numerous replicas and figures, might be much less pronounced. The original interpretation of the “kink” being put down to the fragmented and poor condition of the fossil material. The shape of the upper jaws may be a result of taphonomy and it might not reflect the actual shape of the bones.
Lots of Dilophosaurus Dinosaur Models Feature in Everything Dinosaur’s Video
The Wild Safari Prehistoric World Dilophosaurus model came out in 2009 and it shows the characteristic anatomical traits formerly associated with this theropod dinosaur.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Nasal and Lacrimal Bones Form the Crests
It is the nasal and lacrimal bones that form the famous crests. This new paper suggests that these features were not thin and bony but the hollow, pneumatised cores were covered with keratin or keratinised skin making them much larger than previously thought. Although their overall shape remains uncertain, these crests may have played a role in helping this large animal to lose heat. Recently published research (Eastick et al), suggests that the casques of large, ground-dwelling birds such as cassowaries might act as thermal windows.
The casque on the top of the head of the cassowary could help this large bird to lose heat when it is very hot and restrict heat loss in cooler conditions. At the time of publication (2019), it was proposed that these findings might have implications for the function of similar structures in avian and non-avian dinosaurs and that includes Dilophosaurus wetherilli.
Used for Display and Thermoregulation?
The new interpretation depicts Dilophosaurus as an apex predator which was very bird-like. Those crests could have played a role in thermoregulation.
Picture credit: Everything Dinosaur (puppet of Dilophosaurus created by Brian Engh)
Everything Dinosaur’s YouTube video highlighting the scientific paper on Dilophosaurus that may change the way models of this dinosaur are made lasts for a fraction over eleven minutes. It provides an overview of the recent paper and discusses how future Dilophosaurus dinosaur models might look.
To read Everything Dinosaur’s blog post about the newly published research reviewing the Dilophosaurus wetherilli fossil material: Beefing Up Dilophosaurus.
Everything Dinosaur’s YouTube channel contains over 175 dinosaur and prehistoric animal videos, including model reviews, tips and hints about prehistoric animal model collecting, new releases, fossil discoveries, updates and insider information.
Discover Everything Dinosaur on YouTube: Everything Dinosaur on YouTube. We recommend that you subscribe to our YouTube channel.
Everything Dinosaur would like to acknowledge the help and support of University of Texas at Austin/Jackson School of Geosciences for their help in creating our YouTube video.
Primoptynx poliotauros – Large Owl that Hunted like a Hawk!
With the extinction of the non-avian dinosaurs some 66 million years ago, our mammalian ancestors diversified and thrived. A large proportion of their predators had become extinct and this may have contributed to their success. However, our furry friends were not to have everything go their way, as within a few million years other vertebrates, notably the birds had themselves diversified and begun to fill predatory niches in terrestrial ecosystems once occupied by less derived maniraptorans.
Primoptynx poliotauros
For example, a new species of large owl has been described from postcranial remains found in the Bighorn Basin of Wyoming. This owl, which was approximately sixty centimetres tall, has particularly large and well developed talons on its hind and second toes. Writing in the “Journal of Vertebrate Palaeonotology”, the research team responsible for describing the fossil material conclude that this large bird was a very dangerous threat to the numerous species of small and medium sized mammals within the ecosystem. The owl has been named Primoptynx poliotauros.
The Fossil Remains of Primoptynx poliotauros Laid Out in Skeletal Position
Primoptynx poliotauros fossil bones laid out in approximate skeletal position. Note the scale bar of 10 cm.
Picture Credit: Senckenberg Research Institute/Tränkner
Big Owl with Big Talons
Lead author of the scientific paper, Dr Gerald Mayr, an ornithologist at the Senckenberg Research Institute and Natural History Museum Frankfurt commented:
“The fossil owl was about the size of a modern snowy owl (Bubo scandiacus). However, it is clearly distinguished from all extant species by the different size of its talons. While in present-day owls the talons on all toes are approximately the same size, Primoptynx poliotauros has noticeably enlarged talons on its hind toe and second toe.”
The scientists postulate that as this prehistoric owl has a longer first and second toe, as seen in extant hawks and other members of the Accipitridae family, such as such as the Harpy eagle (H. harpyja), this suggests that P. poliotauros used its feet to dispatch prey items in a hawk-like manner, in contrast to extant owls that kill prey with their beak.
Co-author of the paper, Dr Thierry Smith (Royal Belgian Institute of Natural Sciences), explained:
“Owls today have four toes with claws of equal size to catch relatively small preys and kill them with the beak. Primoptynx poliotauros has a longer first and second toe, as seen in hawks and other members of the family Accipitridae. Those more developed toes are used to pin down prey, which are punctured by the talons. So, it was an owl that hunted like a hawk on medium-sized mammals.”
From the Willwood Formation (Wyoming, USA)
The fossil material heralds from the Willwood Formation of the northern Bighorn Basin, Park County in Wyoming and the genus name is from the Latin for first “primus” and the “ptynx” for owl. Although around 55 million years old, Primoptynx was not the “first owl”, there is evidence to suggest that these birds originated in the Cretaceous.
The fossils help to confirm the widespread and diverse species of owls that were present during the Eocene Epoch. The success of owls (Strigiformes), runs in conjunction with the evolutionary development of placental mammals. The later extinction of Primoptynx poliotauros and prehistoric proto-owls may have been due to the emergence of diurnal birds of prey in the Late Eocene.
Everything Dinosaur acknowledges the assistance of a media release from the Royal Belgian Institute of Natural Sciences in the compilation of this article.
The scientific paper: “Skeleton of a new owl from the early Eocene of North America (Aves, Strigiformes) with an accipitrid-like foot morphology” by Gerald Mayr, Philip D. Gingerich and Thierry Smith published in the Journal of Vertebrate Paleontology.
Study Suggests that Ornithischian and Saurischian Dinosaurs Evolved Around the Same Time
An international team of scientists from Brazil and Argentina in collaboration with a geochronologist from the Massachusetts Institute of Technology (MIT), have provided evidence to support the hypothesis that the Ornithischia and Saurischia diverged early on in dinosaur evolution and this supports the view of the dinosaur family tree as proposed by Seeley in 1887.
Writing in the journal “Scientific Reports”, the researchers which included Jahandar Ramezani (MIT), re-examined the fossils of Pisanosaurus mertii, dating these fossils to approximately 229 million years ago (Late Carnian stage of the Triassic). Pisanosaurus is believed to be the earliest known ornithischian dinosaur, although some palaeontologists have concluded that this one-metre-long reptile is a dinosauriform.
An Analysis of Dinosaur Evolution
This new date suggests that bird-hipped dinosaurs were evolving at around the same as lizard-hipped forms (Saurischia), this challenges the hypothesis proposed by Baron et al in their 2017 paper which re-shaped the traditional view of dinosaur taxonomy.
A View of the Ischigualasto Formation (Foreground)
The famous Ischigualasto Formation (foreground), the Sierra de Famattina Mountains can be seen on the horizon (La Rioja province – Argentina).
Picture credit: Desojo et al
Accurately Dating the Ischigualasto Formation
The researchers focused their fossil finding efforts on the Hoyado del Cerro Las Lajas area, where outcrops of the Ischigualasto Formation can be found, but they are less well explored compared to contemporaneous strata within the “Valley of the Moon” geological park in San Juan Province. Volcanic deposits yielded zircons at various levels and these minerals permitted the measurement of isotopes of uranium and lead (rate of radiometric decay).
The presence of these igneous rocks allowed the geochronologist to measure the relative proportion of isotopes present in the zircon crystals. Radiometric dating permitted the scientists to make an estimate of the age of the bedding planes and infer the age of the fossils that they contain. The study revealed that the Ischigualasto Formation overlaps with the deposition of another important fossil-bearing formation found in North America – the Chinle Formation.
Carefully Jacketing a Specimen Prior to its Removal
A researcher carefully prepares a field specimen for removal.
Picture credit: Desojo et al
Overlapping with the Chinle Formation of the South-western United States
The middle layers of the Chinle Formation which outcrops in the south-western part of the USA contain a variety of vertebrate fossils, including early dinosaurs. However, very few fossils if any, are associated with the lower levels of the Chinle Formation. The lack for fossils, prevents palaeontologists from understanding more about the early radiation and diversity of the Dinosauria from their suspected origins in the southern hemisphere. The rocks from which fossils of the basal ornithischian dinosaur Pisanosaurus have been found were dated to approximately 229 million years ago. From this data, the research team were able to conclude that the earliest bird-hipped dinosaurs evolved at around the same time as the first lizard-hipped dinosaurs appear in the fossil record.
The Scientists Proposed that Pisanosaurus was Indeed an Ornithischian and it Lived Around 229 Million Years Ago
A life reconstruction of the Triassic ornithischian Pisanosaurus.
Dating of the Strata to Determine Dinosaur Evolution
Commenting on the contribution of the dating of the strata to the paper, Jahandar Ramezani stated:
“We can now say the earliest ornithiscians first showed up in the fossil record roughly around the same time as the saurischians, so we shouldn’t throw away the conventional family tree. There are all these debates about where dinosaurs appeared, how they diversified, what the family tree looked like. A lot of those questions are tied to geochronology, so we need really good, robust age constraints to help answer these questions.”
Uranium-bearing Zircon Crystals Allowed an Accurate Date for Parts of the Ischigualasto Formation to be Established
Microscopic crystals of the uranium-bearing mineral zircon were identified in rock samples and these crystals permitted an accurate date for the rock layers to be calculated.
Picture credit: Desojo et al
Everything Dinosaur acknowledges the assistance of a media release from the Earth, Atmospheric and Planetary Sciences department of MIT in the compilation of this article
The scientific paper: “The Late Triassic Ischigualasto Formation at Cerro Las Lajas (La Rioja, Argentina): fossil tetrapods, high-resolution chronostratigraphy, and faunal correlations” by Julia B. Desojo, Lucas E. Fiorelli, Martín D. Ezcurra, Agustín G. Martinelli, Jahandar Ramezani, Átila. A. S. Da Rosa, M. Belén von Baczko, M. Jimena Trotteyn, Felipe C. Montefeltro, Miguel Ezpeleta and Max C. Langer published in Scientific Reports.
Trierarchuncus prairiensis – The Last Alvarezsaurid
A new species of alvarezsaurid dinosaur has been described from fragmentary remains consisting of a foot bone, a partial radius (arm bone) and three thumb claws which might represent a progressive size series. The little dinosaur has been named Trierarchuncus prairiensis and the fossils come from the uppermost Maastrichtian Hell Creek Formation of Montana and demonstrate that these bizarre, little theropods survived until the very end of the Cretaceous.
A Life Reconstruction of the Newly Described Alvarezsaurid T. prairiensis
Trierarchuncus prairiensis life reconstruction.
Picture credit: Badlands Dinosaur Museum (North Dakota) model created by Boban Filipovic
The Most Complete Alvarezsaurid Claw Described to Date
Writing in the journal “Cretaceous Research”, the research team that includes lead author Dr Denver Fowler (Badlands Dinosaur Museum), describe the three thumb claws (manual digit 1) which are of different sizes. They conclude that these three claws probably represent a growth series and from this they can plot how the claw changed as the alvarezsaurid grew. As Trierarchuncus matured, the thumb claw became more robust and roughened.
Blood vessel grooves on the manual ungual (claw) became more deeply embedded in the bone. One claw, the middle-sized specimen, represents the most complete alvarezsaurid thumb claw described to date and it demonstrates that these claws were more curved than previously thought. A powerful, strongly curved thumb claw would have helped this small dinosaur to rip into rotten wood in search of invertebrates. It has also been suggested that alvarezsaurids evolved to exploit termites as a food source, that is, they exhibited termitophagy (specialised consumers of termites). The single claw on each hand in association with strong forelimbs could have been used to tear apart termite nests.
A View of the Three Alvarezsaurid Fossil Claws (Proposed Ontogenetic Series)
The three claws described in the scientific paper form a possible growth series. The most complete alvarezsaurid claw described to date can be seen in the middle. Note the strongly curved and hook-like claw, if this is a growth series, then it has been suggested that the thumb claw became more strongly curved as the animal matured.
Picture credit: Badlands Dinosaur Museum (North Dakota)
Inspired by Captain Hook!
The claws were the inspiration behind the dinosaur’s name. The genus name comes from the Greek “trierarch”, a reference to the appointed officers responsible for a Greek warship, whilst “uncus” is the Latin for hook. The trivial or species name honours the gentle, rolling prairies of eastern Montana where the fossils were found. The name which is pronounced Try-er-arch-unk-cus pray-ree-en-sis translates as “Captain Hook of the prairies”. This is also a nod in the direction of the infamous “Captain Hook”, a fictional character, the nemesis of Peter Pan created by J. M. Barrie.
The Three Thumb Claws from the Alvarezsaurid in the Study
Possible evidence of a growth series – alvarezsaurid manual unguals. The human hand provides a scale, an adult Trierarchuncus was probably less than a metre in length.
Picture credit: Badlands Dinosaur Museum (North Dakota)
Implications for the Taxonomy and Phylogeny of the Alvarezsauroidea
If the three claw specimens do indeed represent a growth series (an ontogenetic series), then this discovery could have far-reaching consequences for all those maniraptoran dinosaurs confined within the Alvarezsauroidea. If the claws of these dinosaurs changed radically as the animal grew and matured, then supposedly unique features (autapomorphies), used to erect other alvarezsaurid genera might be unreliable. These features might be attributed to the relatively young age of the dinosaur when it died, rather than representing a defining anatomical characteristic that can lead to the naming of a new species.
Views of the Thumb Claw Showing Curvature (MOR 6622 – Holotype Claw)
Views of the most complete Trierarchuncus thumb claw showing curvature. The holotype claw MOR 6622.
Picture credit: Badlands Dinosaur Museum (North Dakota)
The Youngest Known Alvarezsaurid
Stratigraphic data indicates that Trierarchuncus represents the youngest known alvarezsaurid. Fossils associated with these types of theropod occur through most of the eighty-five metre thick Hell Creek Formation, with the uppermost specimen having been found within a few metres of the contact with the Palaeocene-aged Fort Union Formation. It is likely that alvarezsaurids were present in North America throughout the Late Cretaceous and that they persisted until the extinction of the non-avian dinosaurs.
The scientific paper: “Trierarchuncus prairiensis gen. et sp. nov., the last alvarezsaurid: Hell Creek Formation (uppermost Maastrichtian), Montana” by Denver W. Fowler, John P. Wilson, Elizabeth A. Freedman Fowler, Christopher R. Noto, Daniel Anduza and John R. Horner published in Cretaceous Research.
Evidence of Sequential Moult Identified in Microraptor gui
A team of Israeli scientists in collaboration with colleagues from China have found evidence in the holotype specimen of Microraptor (Microraptor gui) that this flying dinosaur sequentially moulted its feathers. All living birds have to replace their feathers periodically in order to maintain their function, feathered dinosaurs underwent the same process to. The way in which the feathers are shed and replaced provides palaeontologists with an opportunity to infer habits and behaviours about a long extinct animal.
The Holotype Fossil Material of Microraptor gui
Feathers are found preserved in many dinosaur fossils from China and a new study suggests that Microraptor sequentially moulted which has implications for the habit and behaviour of this volant dromaeosaurid.
Writing in the academic journal Current Biology, the scientists from the University of Haifa, the Society of Protection of Nature and the Jerusalem Bird Observatory (Israel), along with co-workers from the Chinese Academy of Sciences identified signs of sequential moulting on the fossilised wing of Microraptor gui.
Moulting Strategy Links to Habitat Selection and Flight Ability
Living birds generally moult their feathers in one of three main ways or strategies:
1). A gradual direct replacement of all flight feathers in a slow moult with both wings showing similar stages of moult at the same time – referred to as sequential moulting.
2). Simultaneous replacement of all the flight feathers – referred to as simultaneous moulting.
3). A gradual, but not ordered moult in which feather replacement has no predictable sequence or direction – referred to as an irregular moult.
Different Moulting Strategies Identified in Extant Birds
Examples of moult strategies in living birds. Marbled godwit (Limosa fedoa) in (A) showing a gradual sequential moult. The flightless cormorant (Nannopterum harrisi) during a non-sequential moult with both wings showing old, new and growing feathers without any order or symmetry. A common loon (Gavia immer) after simultaneous shedding of all the wing’s feathers as part of a non-sequential simultaneous moult. An African darter (Anhinga rufa) in (D) that is characterised by a non-sequential moult in which its flight feathers grow simultaneously.
Picture credit: Kiat et al plus Gartner, Salmond, S. P. d’Entremont, Francey (Journal of Current Biology)
Moulting Strategies
In total, the moulting strategies of 302 living bird species were studied, including active fliers and ground-dwelling birds incapable of powered flight. These findings were than applied to the feather arrangement, composition and morphology as found in the wing of the Microraptor gui holotype specimen. The researchers were unable to distinguish between simultaneous and irregular moulting (strategy 2 and 3), so they confined their study to a direct comparison between sequential moulting (strategy 1) and non-sequential moulting (strategies 2 and 3).
The moulting strategy adopted by a bird species impacts on their ability to fly and provides clues about their habitat.
For example, those birds that spend much of their time in the air or live in habitats which are open with few hiding places to help them avoid predators, sequential moulting tends to be adopted. This ensures that the birds can still fly even during moulting. Birds that do not fly frequently, or that have access to plenty of hiding places in their habitat so that they can avoid detection by predators tend to shed a large number of feathers simultaneously and have a relatively rapid moult, typically no more than 2-3 weeks, but if they are a volant species their ability to fly is severely impeded during this time.
The Implications for Microraptor gui
A detailed examination of the wing feathers preserved on the holotype specimen of Microraptor led the researchers to identify six feathers of differing sizes (a-g in the diagram below). These feather lengths were in a sequence indicating that Microraptor moulted gradually and sequentially.
Evidence of Sequential Moulting in Microraptor (M. gui)
The holotype specimen exhibits an active moult in the primaries (the arrow points to the moult-related wing gap). The bottom right inset shows how the researchers identified seven primaries in the specimen’s wing, marked as P(a)–P(g).
Picture credit: Kiat et al (Journal of Current Biology)
This suggests that Microraptor probably spent a considerable portion of each day in the air and that it needed to be able to fly to avoid predators and to forage for food. Furthermore, Microraptor required this capability on a daily basis, including during the moulting process.
Wing Moult (Sequential Shedding) in Microraptor
Illustration (A) shows fully grown primary feathers on the wing, whilst (B), shows light grey feathers which have yet to be shed.
Picture credit: Kiat et al (Journal of Current Biology) with additional annotation by Everything Dinosaur
Microraptor gui Demonstrating Sequential Moulting
Microraptor is the earliest known feathered vertebrate to demonstrate sequential moulting and this suggests that this strategy is nested very deep within the Maniraptora lineage that led to the evolution of birds. It likely maintained its flight ability throughout the entire year. These findings support the hypothesis that Microraptor was a strong, capable flier. The researchers conclude that flight was essential for either its daily foraging or escaping from predators and that sequential moulting is the outcome of evolutionary pressures to maintain flight capability throughout the entire annual cycle in both extant birds and non-avialan paravian dinosaurs from 120 million years ago.
Microraptor Probably Sequentially Moulted Which Infers it was a Strong Flier
Showing the iridescent feathers and the bifurcated tailfan of the CollectA Deluxe Microraptor model. New study of the Microraptor gui holotype suggests sequential moulting and from this it is inferred that flight was essential for either Microraptor’s daily foraging or to avoid predators. Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
The picture (above) shows a CollectA Deluxe Microraptor model.
The scientific paper: “Sequential Molt in a Feathered Dinosaur and Implications for Early Paravian Ecology and Locomotion” by Yosef Kiat, Amir Balaban, Nir Sapir, Jingmai Kathleen O’Connor, Min Wang and Xing Xu published in the journal Current Biology.
Comprehensive Review of Dilophosaurus – Paints New Picture of Predator
Researchers from the University of Texas at Austin and the Petrified Forest National Park have published a comprehensive review of Dilophosaurus wetherilli fossil material and revealed that “double-crested lizard” had stronger jaws than previously thought. Those famous skull crests turn out to be more robust as well. Instead of being regarded as a delicately-jawed scavenger, this iconic dinosaur from the Early Jurassic of North America may have been an apex predator.
Previously Thought to be Quite Lightly Built with Delicate Jaws
Wild Safari Dinosaurs compared. Dilophosaurus had been thought to be much more lightly built than other Jurassic theropods. However, a comprehensive review of fossil material suggests that our perceptions regarding Dilophosaurus may have to change.Picture credit: Everything Dinosaur.
Picture credit: Everything Dinosaur
Not a Member of the Ceratosauria Clade?
Writing in the “Journal of Palaeontology”, researchers Adam Marsh (University of Texas Austin) and Timothy Rowe (Division of Resource Management, Petrified Forest National Park, Arizona), conducted an extensive review and re-examination of all the know specimens of Dilophosaurus wetherilli and concluded that this large-bodied theropod was probably not a member of the Ceratosauria or indeed, the Coelophysoidea, but was a stem-averostran theropod, a member of the Averostra clade. As such, D. wetherilli shows a phylogenetic relationship with Cryolophosaurus ellioti which is known from the Early Jurassic of Antarctica and Zupaysaurus rougieri, fossils of which come from the Late Triassic of Argentina.
The Review Included A Reassessment of the Holotype Skull Material
Dilophosaurus wetherilli holotype specimen (UCMP 37302): (1–4) articulated right side of the skull and line drawings. Plus (5, 6) nasolacrimal crest, (7, 8) left postorbital, (9, 10) left lacrimal, (11, 12) left quadratojugal, and (13, 14) left squamosal in (1, 2, 5, 7, 9, 11, 13) lateral and (3, 4, 6, 8, 10, 12, 14) medial view.
Picture credit: Marsh et al (Journal of Palaeontology)
Dilophosaurus wetherilli
With an estimated body length of around six metres, D. wetherilli is one of the largest terrestrial predators known from the Early Jurassic of North America. Despite extensive study of the fossil material and this dinosaur’s on-going popularity with the public due to its depiction as a venom-spitting, frilled dinosaur in the first “Jurassic Park” film released in 1993, much of the animal’s skeleton, anatomy, ontogeny and taxonomic relationship with other members of the Theropoda remains unknown.
Using fossils collected from the middle and lower portions of the Kayenta Formation (Navajo Nation, northern Arizona), the scientists comprehensively reviewed the holotype cranial material (UCMP 37302). In addition, previously undescribed specimens were analysed and it was concluded that the fossils represent a single species, a large, crested theropod within the Kayenta Formation. This suggests that Dilophosaurus, as a species, persisted for a long time – several million years.
Dilophosaurus Fossil Finds in the Navajo Nation
Localities from which Dilophosaurus wetherilli (Welles, Reference Welles 1954) has been collected in northern Arizona. The shaded region in the north-eastern corner of the state represents the Navajo Nation. The inset stratigraphic column idealizes the section near Tuba City and Gold Spring, Arizona. The dark green unit underlying the Kayenta Formation represents the Moenave Formation and the Wingate Sandstone in the western and eastern half of the Navajo Nation, respectively. Outcrop area modified from Cooley et al (1969).
Picture credit: Marsh et al (Journal of Palaeontology)
It is noted that many anatomical characteristics of the skeleton are more derived when compared to Late Triassic theropods, adaptations to a larger body size and a more robust macropredatory habit.
An Articulated Hindlimb Assigned to D. wetherilli
Dilophosaurus wetherilli referred specimen (TMM 43646-1): articulated right hindlimb.
Picture credit: Marsh et al (Journal of Palaeontology)
Dilophosaurus an Apex Predator
Previous research had suggested that Dilophosaurus had weak jaws and this may have influenced how this dinosaur was depicted in the “Jurassic Park” franchise. This review identified areas of attachment for powerful jaw muscles and that the skeleton was pneumatised (air pockets) and these structures would have helped to both lighten and strengthen the skull. The authors state that whilst Dilophosaurus could catch small animals and even catch fish in the fluvial environment with which its fossils are associated, the robust upper jaw and strong grasping hands suggest that it was equipped to tackle far larger prey.
The idea of Dilophosaurus being a much more powerful and dangerous animal is supported by the discovery of partially articulated specimens of the early sauropodomorph Sarahsaurus (S. aurifontanalis) containing large bite marks alongside shed teeth and a skeleton of Dilophosaurus wetherilli within the same quarry as reported by Rowe et al in 2011.
A Dilophosaurus Braincase
During the comprehensive review, the researchers were able to assign to the Dilophosaurus genus a number of other specimens that had come from the Kayenta Formation, including a remarkably-well preserved small braincase from a juvenile.
Commenting on their fortuitous find Dr Marsh stated:
“In the midst of the analysis, we discovered that a small braincase in the Jackson School’s collections belonged to a Dilophosaurus wetherilli. We realised that it wasn’t a new type of dinosaur, but a juvenile Dilophosaurus wetherilli, which is really cool.”
The More Robust Rebor Figures Introduced in 2019 May Represent a More Accurate Depiction of Dilophosaurus wetherilli
The Rebor Dilophosaurus replicas “Green Day” and “Oasis”. A new study suggests that the jaws and bony crests of Dilophosaurus wetherilli were more robust than previously thought.
Picture credit: Everything Dinosaur
The picture (above) shows the Rebor Dilophosaurus figures.
The strong jaws coupled with the powerful forelimbs suggests that Dilophosaurus was an active predator rather than a scavenger. It seems that many palaeontologists perceptions regarding Dilophosaurus wetherilli will have to be reconsidered, science as well as the film industry might have got this dinosaur all wrong.
The scientific paper: “A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona” by Adam D. Marsh and Timothy B. Rowe published in the Journal of Palaeontology.
