Caelestiventus hanseni – Rare Pterosaur Fossil Sheds Light on Triassic Pterosaur Diversity

A team of scientists have published a paper in the journal “Nature Ecology & Evolution”, detailing the discovery of a new type of Triassic pterosaur.  The exquisitely preserved fossils, including skull and jaw material excavated from strata laid down at a desert oasis that existed around 210 million years ago, has got vertebrate palaeontologists in a flap.

Caelestiventus hanseni

Firstly, only around thirty fossils of Triassic pterosaurs are known, most of these from only fragmentary remains and secondly, as this flying reptile fossil is associated with a desert environment, it suggests that by the Late Triassic the Pterosauria were very specious and had already adapted to a variety of different habitats.  If all this wasn’t enough to get scientists excited, the exceptional state of preservation has revealed anatomical features previously obscured in other early pterosaurs and shows that this new flying reptile from Utah, was closely related to Dimorphodon macronyx which is known from Lower Jurassic rocks from Dorset (southern England).

The flying reptile was large, very large for a Triassic pterosaur, it had an estimated wingspan of 1.5 metres.  It has been named Caelestiventus hanseni (pronounced Sel-less-tees-vent-us han-son-eye).

A Life Restoration of the Newly Described Late Triassic Pterosaur Caelestiventus hanseni

Caelestiventus hanseni illustration.
Caelestiventus hanseni illustration. Study of the fossil bones suggests the presence of a throat pouch.

Picture credit: Michael Skrepnick

From Saints and Sinners Quarry (Utah)

The fossils come from a vertebrate bone bed located in the Saints and Sinners Quarry, within sandstone deposits in north-eastern Utah.  Numerous vertebrate fossils have been associated with this locality including crocodylomorphs and theropod dinosaur material.

The bones come from silty, fine-grained sandstones laid down in near-shore waters of an oasis, that was surrounded by arid desert.  More than 18,000 individual bones representing a total of nine tetrapod taxa (including two theropod dinosaurs), have been found.  The flying reptile bones described in the scientific paper are the only ones known from this deposit and Caelestiventus hanseni is the first Triassic pterosaur from the western hemisphere from outside Greenland.

Whether this flying reptile was a resident of the oasis is unclear, but it is possible that this individual was an occasional visitor, to what would have been, an isolated oasis surrounded by extensive dune fields.

One of the Delicate Skull and Jaw Fossils Held by Professor Brooks Britt (Brigham Young University)

Holding fossils of Caelestiventus hanseni.
Professor Brooks Britt (Brigham Young University) holds one of the pterosaur fossils (jaw and skull fossils). His finger is pointing to roughly where the eye socket would have been.

Picture credit: Brigham Young University

The picture above, shows a prepared piece of the fossilised skull of C. hanseni (maxilla and other elements from the jaws and skull), the specimen is held by Professor Brooks Britt of Brigham Young University and the lead author of the scientific paper.  It is not possible to remove the delicate, three-dimensional fossils from the matrix, the fossils would collapse under their own weight, but CT scans in conjunction with computer modelling enabled the production of precise plastic replicas of the fossil pieces, that gave the researchers the opportunity to reconstruct the skull.

Related to Dimorphodon (D. macronyx)

The beautiful state of preservation enabled the research team to gain fresh insights into the morphology of skull and jaws of Late Triassic pterosaurs.  The reconstructed brain case reveals that those parts of the brain responsible for processing vision were particularly well-developed, reinforcing the theory that flying reptiles had very keen eyesight.

A phylogenetic analysis undertaken by the researchers reveals that Caelestiventus is a sister taxon of Dimorphodon macronyx, which is known from Lower Jurassic rocks from Dorset.

A Three-Dimensionally Printed Skull of Caelestiventus hanseni

Line drawings and three dimensional model.
C. hanseni model skull and line drawing comparisons between C. hanseni and D. macronyx.

Picture credit: Brigham Young University with additional annotation by Everything Dinosaur

The use of CT scans and computer software to digitally remove the fossils from their matrix without damaging them has enabled the scientists to produce extremely accurate three-dimensional images of the specimen, these data files can then be shared with other vertebrate specialists across the world.

A spokesperson from Everything Dinosaur commented:

“The scans permitted the production of finely detailed and extremely accurate three-dimensional models of the individual bones.  When these were fitted together this gave the scientists the opportunity to study the entire skull and to share this information very easily with other palaeontologists.  The use of technology is now helping scientists to gain much easier access to important fossil finds.”

The Geographical Significance of Caelestiventus hanseni

Not only is Caelestiventus hanseni the first record of a Triassic pterosaur from North America, the discovery suggests that by the Late Triassic, flying reptiles were not only quite large but also that they may have already adapted to a wide variety of habitats.  Similarly aged fossils from Greenland and Europe indicate pterosaurs living in forested areas and coastal environments on the super- continent of Pangaea. 

This fossil discovery demonstrates that early pterosaurs were geographically widely distributed and ecologically diverse, even living in harsh desert environments.  C. hanseni is the only record of a desert-dwelling, non-pterodactyloid pterosaur and predates all known desert living pterosaurs by more than sixty-five million years.

The Geographical Significance of the Utah Pterosaur Fossil Discovery

The geographical location of the pterosaur find.
The location of the Triassic pterosaur find from Utah plotted against a map of Pangaea during the Late Triassic and other pterosaur fossil discoveries from Triassic strata.

Picture credit: Brigham Young University

The picture above shows (top left), the location of Utah in the United States and (insert), the geological formations associated with north-western Utah.  The world map shows the location of Triassic pterosaur fossil discoveries superimposed on an illustration of Pangaea with a colour key to indicate different habitats.  Caelestiventus is the first Triassic pterosaur identified from a desert environment.

For flying reptile models and prehistoric animal figures: Everything Dinosaur Prehistoric Animal Figures.

The genus name is from the Latin for “heavenly wind”, in recognition of the volant capabilities of this reptile.  The trivial name honours geologist Robin L. Hanson of the Bureau of Land Management, who has played a crucial role in the excavation of the Saints and Sinners Quarry material.

Photographs Showing Some of the Fossil Material Associated with the Caelestiventus Genus

Caelestiventus hanseni fossil material.
Views of the pterosaur fossil material – Caelestiventus hanseni.

Picture credit: Brigham Young University

To read Everything Dinosaur’s 2015 article that first broke the news of this pterosaur fossil discovery: Fearsomely-fanged Triassic Pterosaur from Utah.