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)

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

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

Picture credit: Danielle Dufault (Royal Ontario Museum)

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.

The Everything Dinosaur website: Everything Dinosaur.

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

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.

The Everything Dinosaur website: Everything Dinosaur.

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

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)

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

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)

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.

Evidence suggests that alvarezsaurids originated in Asia: Haplocheirus – Is it a bird?  No, it is a dinosaur.

Did alvarezsaurids eat eggs?  An article from 2018: Did Alvarezsaurids eat eggs?

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.

Visit the Everything Dinosaur website: Everything Dinosaur.