A new pterosaur species has been described based on a superbly preserved specimen found in Upper Jurassic limestone deposits in Bavaria (southern Germany). The fully articulated specimen displays a unique dentition that suggests this flying reptile fed like a modern-day flamingo, sieving water through its jaws to trap small invertebrates as it waded or possibly swam in a shallow lagoon.

Picture credit: Megan Jacobs

Balaenognathus maeuseri

The pterosaur has been classified as a ctenochasmatid, a group of short-tailed pterodactyloids characterised by specialised teeth adapted for filter feeding. Fossils of these relatively small flying reptiles (most with wingspans less than 3 metres), have been found in Europe, America and China, in rocks dating from the Upper Jurassic to the Early Cretaceous. The new pterosaur has been named Balaenognathus maeuseri, the genus name derives from the scientific name for the Bowhead whale (Balaena mysticetus) and the Latin for jaw, as it is thought that these two unrelated species shared a common feeding strategy. The specific epithet honours a co-author of the paper Matthias Mäuser who sadly passed away before publication.

Lead author of the study, published in Paläontologische Zeitschrift (PalZ), Professor David Martill from the University of Portsmouth School of the Environment, Geography and Geosciences commented:

“The nearly complete skeleton was found in a very finely layered limestone that preserves fossils beautifully.”

Unique Pterosaur Dentition

The fossil (specimen number NKMB P2011-63), is remarkable for its completeness, unusual dentition and hints of the preservation of soft tissues, including wing membranes. The delicate jaws contain at least 480 fine teeth.”

Professor Martill added:

“The jaws of this pterosaur are really long and lined with small fine, hooked teeth, with tiny spaces between them like a nit comb. The long jaw is curved upwards like an avocet and at the end it flares out like a spoonbill. There are no teeth at the end of its mouth, but there are teeth all the way along both jaws right to the back of its smile.”

Bizarre Hook-like Tooth Crown

The tips of the jaw are devoid of teeth, which would have permitted plankton and invertebrate-rich water to rush into the long jaw. The hundreds of teeth would have acted as a sieve helping to strain out food. Many of the teeth have a hook-like expansion on the tip of the crown, a bizarre and unique tooth morphology.

Explaining the significance of these strange teeth, Professor Martill stated:

“What’s even more remarkable is some of the teeth have a hook on the end, which we’ve never seen before in a pterosaur ever. These small hooks would have been used to catch the tiny shrimp the pterosaur likely fed on – making sure they went down its throat and weren’t squeezed between the teeth.”

A New Pterosaur

The discovery was made accidentally while scientists were excavating a large block of limestone containing crocodilian fossil remains.

Professor Martill explained:

“This was a rather serendipitous find of a well-preserved skeleton with near perfect articulation, which suggests the carcass must have been at a very early stage of decay with all joints, including their ligaments, still viable. It must have been buried in sediment almost as soon as it had died.”

Most members of the Ctenochasmatidae family seem to have been the pterosaur equivalent of wading shore birds, although some genera were perhaps adapted to habitats further inland and have truly bizarre shaped jaws leaving palaeontologists perplexed as to what they ate.

Only one other known pterosaur had more teeth than Balaenognathus. It is another ctenochasmatid and it is called Pterodaustro guinazui and its fossils are known from the Lower Cretaceous of Argentina. Both Pterodaustro and Balaenognathus were likely filter feeders although the arrangement of their teeth differs. Balaenognathus had teeth in the upper and lower jaw which are the mirror image of each other, whilst P. guinazui had very reduced teeth in the upper jaw and up to a 1,000 densely packed, bristle-like teeth in the lower jaw.

New Pterosaur Species – Unique Feeding Mechanism

The teeth of Balaenognathus suggest a feeding strategy that involved the animal either wading through water or swimming, using its spoon-shaped beak to funnel water into its mouth, this water was then strained through its teeth to trap prey. The researchers propose that Balaenognathus fed on shrimps and copepods filling a similar ecological niche as extant ducks, shorebirds and flamingos.

Commenting on the sad passing of Matthias Mäuser, Professor Martill said:

“Matthias was a friendly and warm-hearted colleague of a kind that can be scarcely found. In order to preserve his memory, we named the pterosaur in his honour.”

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

The scientific paper:

The scientific paper: “A new pterodactyloid pterosaur with a unique filter‑feeding apparatus
from the Late Jurassic of Germany” by David M. Martill, Eberhard Frey, Helmut Tischlinger, Matthias Mäuser, Héctor E. Rivera‑Sylva and Steven U. Vidovic published in Paläontologische Zeitschrift (PalZ).

In today’s blog post we look at the dwarf nodosaurid Patagopelta (P. cristata), which was formally named and described earlier this month.

A new, very small, armoured dinosaur has been named and described from fossils found in Argentina. The dinosaur which measured around 2 to 2.3 metres in length (based on the dimensions of the femur), suggests that some members of the Nodosauridae in Gondwana became smaller in the Late Cretaceous, perhaps as armoured dinosaurs in South America were under evolutionary pressure from other ornithischians and titanosaurs.

Dwarf Nodosaurid Patagopelta

Fragmentary remains of Late Cretaceous armoured dinosaurs are known from Chile and Argentina, but little work had been undertaken to assess these specimens and to review their phylogeny and taxonomic relationship with other members of the Ankylosauria clade from North America and elsewhere in the world.

Writing in the ” Journal of Systematic Palaeontology”, the researchers led by Facundo Riguetti, a CONICET doctoral fellow, reassessed the known ankylosaur material in conjunction with some other recently found fossils and, as a result, they were able to establish a new nodosaurid species from bones and a single tooth found in sediments of the Allen Formation (Campanian–Maastrichtian) in Salitral Moreno, Río Negro Province (northern Patagonia).

Patagopelta cristata

The dinosaur’s genus name translates as “Patagonian shield” whilst the trivial name derives from the Latin for crest – a reference to the diagnostic crests on both the anterior surface of the femur and the lateral osteoderms of the cervical rings.

Dr Riguetti commented:

“The importance of the study lies in the fact that Patagopelta is the first species of Ankylosauria described for the continental territory of Argentina, which fills the existing gap for this group and adds a new thyreophoran to the very few incomplete and indeterminate remains known for our country from this type of ornithischian dinosaur.”

The Right Femur

The best-preserved fossil element is the right femur, which is complete and shows typical anatomical characteristics associated with the Nodosauridae. This bone along with the distinctive cervical osteoderms led to the erection of this new species. As the femur is only 25 cm in length and bone histology suggests an adult animal, the researchers conclude that Patagopelta was a dwarf form of armoured dinosaur.

Co-author Sebastián Apesteguía, a CONICET researcher, explained:

“For an armoured dinosaur, Patagopelta is extremely small. Due to the size of the femur, only 25 centimetres in length, we estimate that the animal must have been between two and three meters long, while, in general, ankylosaurs are medium-sized or large animals, with an average length of between four and five metres.”

A Faunal Exchange Across the Americas

Although it is thought that the Nodosauridae evolved in the Northern Hemisphere, towards the end of the Cretaceous (Campanian – Maastrichtian), a land bridge existed between North America and South America that permitted a faunal exchange. Titanosaurs migrated north, which explains why fossils of titanosaurs such as Alamosaurus occur in the USA. Ornithischian dinosaurs such as hadrosaurs and nodosaurids moved south.

The image above shows a typical Late Cretaceous titanosaur, for models of Late Cretaceous dinosaurs including titanosaurs and armoured dinosaurs: CollectA Prehistoric Life Models.

Sebastián Apesteguía added:

“That is why in South America we only expect to find animals like Patagopelta in rocks from the Late Cretaceous, just before the global extinction of the dinosaurs took place.”

Dwarfism in Late Cretaceous South American Thyreophora

The size of Patagopelta along with the recently described Stegouros (Soto-Acuña et al, 2021)*, from southernmost Chile, suggests that armoured dinosaurs in South America may have gradually become smaller. This trait is not known in members of the Thyreophora described from other parts of the world. Palaeontologists have speculated that perhaps competition from titanosaurs and the migration of hadrosaurs into South America might have led to armoured dinosaurs adapting to different ecological niches to avoid competition. By being smaller these animals needed fewer resources than larger, contemporaneous herbivorous dinosaurs.

It has also been suggested that the geology of Patagonia where the fossils of Patagopelta were found might provide a clue to the dwarfism. Geologists are aware of several Late Cretaceous marine transgressions in the region. This might have led to the establishment of an island archipelago with dinosaurs living on these small islands gradually become smaller due to a scarcity of resources (the “island rule”).

Tracks of Dwarf Ankylosaurs

Members of the Patagopelta research team had previously described tracks of dwarf ankylosaurs, possibly affected by similar circumstances, preserved in Upper Cretaceous deposits in Bolivia.

*To read Everything Dinosaur’s 2021 article about the discovery of Stegouros: New Armoured Dinosaur from Chile.

Everything Dinosaur acknowledges the assistance of a media release from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) in the compilation of this article.

The scientific paper: “A new small-bodied ankylosaurian dinosaur from the Upper Cretaceous of North Patagonia (Río Negro Province, Argentina)” by Facundo Riguetti, Xabier Pereda-Suberbiola, Denis Ponce, Leonardo Salgado, Sebastián Apesteguía, Sebastián Rozadilla and Victoria Arbour published in the Journal of Systematic Palaeontology.

The first, definitive proof of a dinosaur eating a mammal has been found. A foot of a tiny, mouse-sized mammal has been discovered inside the body cavity of the feathered theropod Microraptor (M. zhaoianus). Previously, other Microraptor specimens from Lower Cretaceous rocks of northern China had revealed the fossilised remains of a fish, a primitive bird and a lizard associated with the body cavity. Palaeontologists now know that this crow-sized predator also ate mammals. This is the first record of a dinosaur consuming a mammal.

Mammal Foot Found Inside Ribcage

A new study led by Dr David Hone (Queen Mary University of London), published in the academic “Journal of Vertebrate Paleontology”, documents the first known incident of a dinosaur having eaten a mammal.

Microraptor is a genus of small, dromaeosaurid which lived in the forests of northern China around 120 million years ago (Early Cretaceous). The remarkable fossils found in Liaoning Province have enabled palaeontologists to build up a detailed picture of life in these ancient, dinosaur-dominated forests.

Researchers have also identified a wide variety of mammals and mammaliamorphs that co-existed with the dinosaurs and pterosaurs. Together these creatures make up a diverse ecosystem known as the Jehol biota

To read Everything Dinosaur’s blog post from 2021 describing the remarkable diversity of vertebrates associated with the Jehol biota: The Jehol Biota.

Microraptor had long feathers on its arms and legs and was, very probably arboreal, gliding from tree to tree, hunting out small animals to eat.

Spotting the Fossilised Foot

The Microraptor specimen was first described twenty-two years ago, but the preserved remains of the tiny foot had been overlooked. Professor Hans Larsson of McGill University in Montreal spotted what others had missed – the remains of another animal inside the Microraptor’s rib cage. In collaboration with Dr Hone, and colleagues from Canada, China and the USA, a paper describing this remarkable discovery has now been published.

Dinosaur Eating a Mammal

The mammal foot is almost complete and belonged to a very small animal, approximately the size of a modern house mouse. Examination of the bones suggest that it was one that predominantly lived on the ground and was not well adapted for climbing trees, making it an interesting prey choice for the mainly arboreal Microraptor.

Previous studies have revealed other Microraptor specimens containing the remains of a bird, a lizard and a fish. This specimen of the species Microraptor zhaoianus demonstrates that Microraptor also consumed small mammals. This little feathered dinosaur was a generalist, consuming a wide variety of prey.

It is not certain if the dromaeosaurids in question had directly preyed upon and eaten these animals or found them already dead and had scavenged them (or a mixture of both) but the mammal at least falls into the range of typical prey size predicated for a predator the size of Microraptor.

Dr Hone’s co-authors on the paper include Dr Alex Dececchi, Mount Marty College (USA), Dr Corwin Sullivan at the Department of Biological Sciences, University of Alberta, and Professor Xu Xing at the Institute of Vertebrate Palaeontology and Palaeoanthropology, Beijing.

A Significant Fossil Discovery

Commenting on the significance of this fossil discovery, Dr David Hone stated:

“It’s so rare to find examples of food inside dinosaurs so every example is really important as it gives direct evidence of what they were eating.“

Dr Hone from the University’s School of Biological and Behavioural Sciences added:

“While this mammal would absolutely not have been a human ancestor, we can look back at some of our ancient relatives being a meal for hungry dinosaurs. This study paints a picture of a fascinating moment in time – the first record of a dinosaur eating a mammal – even if it isn’t quite as frightening as anything in Jurassic Park.”

Co-author of the study, Dr Alex Dececchi, from Mount Marty College, commented:

“The great thing is that, like your housecat which was about the same size, Microraptor would have been an easy animal to live with but a terror if it got out as it would hunt everything from the birds at your feeder to the mice in your hedge or the fish in your pond.”

Everything Dinosaur acknowledges the assistance of a media release supplied by Dr David Hone in the compilation of this article.

The scientific paper: “Generalist diet of Microraptor zhaoianus included mammals” by Hone, D.W.E., Dececchi, T.A., Sullivan, C., Xu, X. and Larsson, H.C.E. published in the Journal of Vertebrate Paleontology.

Correction

This is not the first recorded incidence of a dinosaur consuming a mammal. The press release, although provided by the appropriate authorities, had failed to recognise evidence cited in an earlier scientific paper.