Scientists from Virginia Tech and Des Moines University in the USA have challenged the idea that spheres identified under high magnification in thin sections of fossilised dinosaur bone are preserved fragments of dinosaur blood. The reddish coloured circular structures might not be remnants of blood cells, but instead they could be sediments that have been altered physically, chemically or via biological action to provide misleading data.

That is the conclusion made by the authors of a scientific paper published recently in the peer-reviewed, open-access journal PeerJ.

Photograph of sampled specimen (Beipiaosaurus inexpectus, IVPP V11559) (A) and transmitted light micrographs of representative thin sections (B–D). In the section images black arrows indicate spheres (putatively identified as red blood cells), white arrows indicate osteocyte lacunae and grey arrows indicate non-spherical vessel fills. The researchers suggest the spheres are not evidence of dinosaur blood. Picture credit: Korneisel et al.

Picture credit: Korneisel et al

Analysing the Holotype of Beipiaosaurus inexpectus

The researchers, who included Sterling J. Nesbitt (Department of Geosciences at Virginia Tech), analysed thin sections of bone from the holotype of the Chinese therizinosaur Beipiaosaurus inexpectus from the Jehol Lagerstätte. The fossil specimen (IVPP V11559) consists of both cranial and postcranial elements and it was found in sediments representing the Yixian Formation. This specimen was the subject of a paper earlier this year, remarkably when B. inexpectus was scientifically described only the skull elements were examined in detail. In October (2021), Everything Dinosaur published a blog post on the study of the postcranial material which provided more anatomical traits to help define this genus and clarify the evolution of the Therizinosauridae.

Our post can be found here: Beipiaosaurus Revisited.

In this study, the researchers employed a variety of sophisticated techniques including Ramon spectroscopy, X-ray spectrometry and Time of flight – secondary ion mass spectrometry to analyse thin sections of fossil bone from the Beipiaosaurus and compare them to similarly prepared thin sections of fossilised wood.

The team found that the bone had been dramatically altered by the fossilisation process (taphonomy). Vascular canals in the bone, once thought to contain preserved red blood cells, were filled with a mix of clay minerals and carbonaceous compounds. The spheres that were identified could not be analysed in isolation, but the researchers did not find any evidence of pyrite or haemoglobin fragments associated with a concentration of iron.

However, similar spheres were identified in the thin sections of fossilised wood which were found close to the Beipiaosaurus fossils and as such, had presumably been subjected to the same taphonomic processes.

Transmitted light micrographs of fossil wood found near to the dinosaur fossil material seem to show similar, microscopic spherical structures. The blue arrows highlight small and large examples. At higher magnification (B) these spheres appear to consist of small crystals. Picture credit: Korneisel at al.

Picture credit: Korneisel et al

The researchers concluded that the reddish coloured spheres were not evidence of dinosaur blood, but more likely structures formed by diagenesis. Diagenesis is the process whereby sediments in sedimentary rocks are altered by the interaction of water, microbial activity or by physical and chemical processes.

This research suggests that further study of alleged red blood cells associated with fossil bone is required in order to confirm the assertions made in previous papers.

The scientific paper: “Putative fossil blood cells reinterpreted as diagenetic structures” by Dana E. Korneisel, Sterling J. Nesbitt, Sarah Werning and Shuhai Xiao published in PeerJ.

The award-winning Everything Dinosaur website: Dinosaur Models and Figures.

A new species of Early Cretaceous ichthyosaur has been named and described following the study of fossilised remains found in Columbia. The fossils had previously been assigned to the ophthalmosaurian Platypterygius, but researchers from Canada, Germany and Columbia have erected a new species Kyhytysuka sachicarum.

An examination of the teeth in the jaws of the 94-cm-long skull, found that the anterior teeth were small whilst the teeth towards the back of the jaw were much bigger and robust. The researchers, who include Hans Larsson (Director of the Redpath Museum at McGill University), conclude that this ichthyosaur evolved unique dentition that enabled it to despatch large prey such as other marine reptiles.

A life reconstruction of the newly described, Early Cretaceous ichthyosaur Kyhytysuka sachicarum. Picture credit: Dirley Cortés.

The First Ichthyosaur Fossils from Columbia to be Described

The fossil specimen, consisting of a relatively uncrushed skull, preserved in three-dimensions, was the first definitive ichthyosaur material to have been found in Columbia (Paja Formation). The material was compared to other South American ichthyosaur fossils and assigned to the Platypterygius genus, being formally described and assigned to a new species – P. sachicarum in 1997.

Writing in the “Journal of Systematic Palaeontology”, the research team concluded that this fossil should really be placed in its own separate genus. The name Kyhytysuka translates from the ancient Muisca culture of central Columbia as “the one that cuts with something sharp”, a nod to the heterodont dentition in the jaw.

Hans Larsson explained:

“This animal evolved a unique dentition that allowed it to eat large prey. Whereas other ichthyosaurs had small, equally sized teeth for feeding on small prey, this new species modified its tooth sizes and spacing to build an arsenal of teeth for dispatching large prey, like big fishes and other marine reptiles.”

A Columbian Researcher Assists with the Study

This is an exciting opportunity for graduate researcher and co-author Dirley Cortés, who hopes to be able to continue to study Columbian marine reptiles, as she grew up in the mountainous area of Columbia close to where this fossil was discovered.

Columbian researcher Dirley Cortés studying the skull of Kyhytysuka which was discovered in Columbia. Picture credit: Dirley Cortés.

A Fearsome Predator

The dentition of Kyhytysuka sachicarum is unique among ichthyosaurs. This ichthyosaur had heterodont dentition (teeth of different shapes and sizes in the jaw), the teeth at the front of the jaw were small and designed to pierce, further along the jaw the teeth were larger, and adapted to cut flesh, whilst teeth at the back of the jaw were more robust and better at crushing. These teeth and other skull adaptations imply that Kyhytysuka evolved as an apex predator specialising in the hunting and consuming of large vertebrates such as fish and other marine reptiles. As such, this is the first example of a Cretaceous hypercarnivorous ichthyosaur. A hypercarnivore is defined as an organism whose diet consists of at least 70% meat.

A scale drawing of the fearsome Kyhytysuka ichthyosaur from the Early Cretaceous of Columbia. Known bones are shown in white. Picture credit: Dirley Cortés.

The scientific paper: “Re-appearance of hypercarnivore ichthyosaurs in the Cretaceous with differentiated dentition: revision of ‘Platypterygius’ sachicarum (Reptilia: Ichthyosauria, Ophthalmosauridae) from Colombia” by Dirley Cortés, Erin E. Maxwell and Hans C. E. Larsson published in the Journal of Systematic Palaeontology.

For models and replicas of marine reptiles and other prehistoric animals: Prehistoric Animal Models.