A Small Azhdarchoid Pterosaur from Late Cretaceous British Columbia

As the Cretaceous progressed, so the once diverse and dominant Pterosauria began to be replaced by the rapidly evolving and radiating Aves (birds).  When it came to aeronautics, feathers were better than flaps of skin.  The last of the flying reptiles, those that survived into the very Late Cretaceous were giants, huge animals some as tall as a giraffe, even the smallest of these pterosaurs, creatures like Montanazhdarcho minor and Eurazhdarcho langendorfensis had wingspans comparable to the largest volant birds today.  It seemed that the last of the pterosaurs, most of which belong to a single family, the Azhdarchidae, were all big.

British Columbia Pterosaur Flies Against Conventional Thinking

The small azhdarchoid pterosaur from Hornby Island (British Columbia).

Picture credit: Mark Witton

Studying Pterosaurs

The consensus went something like this, smaller pterosaurs were gradually out competed by and replaced by birds.  However, a newly described pterosaur fossil from British Columbia, the first of its kind from western North America has challenged this thinking.  It seems that smaller pterosaurs did survive into the Late Cretaceous and their lack of presence in the fossil record probably has more to do with preservation basis than with an inability to compete with birds.

The fossilised remains of a small-bodied pterosaur, an animal that probably had a wingspan of around 1.5 metres, that’s roughly the size of an adult European Herring Gull wingspan (Larus argentatus), were found on Hornby Island, a small body of land on the east coast of Vancouver Island, British Columbia back in 2009.  The fragmentary fossils, were located in carbonate nodules and date from approximately 77 million years ago (Campanian faunal stage of the Cretaceous), the finder, a volunteer with the Royal British Columbia Museum, donated the specimen to the Museum.

For models and replicas of pterosaurs and other prehistoric animals: CollectA Deluxe Scale Models and Figures.

Studying a Pterosaur Fossil Specimen

At the time, the fossil material was given to Victoria Arbour, a then PhD student and dinosaur expert at the University of Alberta.  Victoria, as a postdoctoral researcher at North Carolina State University and the North Carolina Museum of Natural Sciences, then contacted Elizabeth Martin-Silverstone, a palaeobiology PhD student (University of Southampton) and the Royal British Columbia Museum sent the specimen for analysis in collaboration with Dr Mark Witton, a pterosaur expert at the University of Portsmouth.

The Pterosaur Fossilised Bones can be Identified in the Carbonate Nodules

The unprepared fossil material in the carbonate nodules.

Picture credit: Sandy McLachlan

Adding to our Knowledge Base About Late Cretaceous Pterosaurs

The fossils comprising a partial humerus (upper arm bone), vertebrae and other bone fragments show characteristics that led them to be classified as azhdarchoid pterosaur material.  Previous studies suggest that the Late Cretaceous skies were only occupied by much larger pterosaur species and birds, but this new finding, which is reported in the Royal Society journal “Open Science”, provides crucial information about the diversity and success of Late Cretaceous pterosaurs.

Lead author, PhD student Elizabeth Martin-Silverstone, explained the significance of this British Columbian discovery:

“This new pterosaur is exciting because it suggests that small pterosaurs were present all the way until the end of the Cretaceous, and weren’t out competed by birds.  The hollow bones of pterosaurs are notoriously poorly preserved, and larger animals seem to be preferentially preserved in similarly aged Late Cretaceous ecosystems of North America.  This suggests that a small pterosaur would very rarely be preserved, but not necessarily that they didn’t exist.”

Photographs and Line Drawings of the Azhdarchoid Humerus

Line drawings and photographs of the prepared humerus (RBCM.EH.2009.019.0001).

Picture credit: Royal Society Open Science

An Azhdarchoid Humerus

The picture above shows photographs and interpretative line drawings of the fossilised left humerus (a, b) dorsal view, (c, d) ventral view, (e, f) proximal and (g, h) distal view.  The shading denotes preserved bone cortex (white), weathered bone (light grey) and matrix infill (dark grey).  The scale bar in the picture equals ten millimetres, indicating a cat-sized Pterosaur.

Late Cretaceous Pterosaur No Bigger Than a Domestic Cat

Late Cretaceous pterosaur that was cat-sized.

Picture credit: Mark Witton

Dr Witton commented:

“The specimen is far from the prettiest or most complete  pterosaur fossil you’ll ever see, but it’s still an exciting and significant find.  It’s rare to find pterosaur fossils at all because their skeletons were lightweight and easily damaged once they died, and the small ones are the rarest of all.  But luck was on our side and several bones of this animal survived the preservation process.

Happily, enough of the specimen was recovered to determine the approximate age of the pterosaur at the time of its death.  By examining its internal bone structure and the fusion of its vertebrae we could see that, despite its small size, the animal was almost fully grown.  The specimen thus seems to be a genuinely small species, and not just a baby or juvenile of a larger pterosaur type.”

Small Pterosaurs in the Late Cretaceous

Although the scientists cannot be sure what this pterosaur actually looked like, it has been given the typical skull and toothless beak of an azhdarchid, although in reality little can be deduced from the fragmentary fossil as to the appearance of this Late Cretaceous flying reptile.  However, the British Columbian fossil discovery is extremely important, as Elizabeth Martin-Silverstone added:

“The absence of small juveniles of large species – which must have existed – in the fossil record is evidence of a preservational bias against small pterosaurs in the Late Cretaceous.  It adds to a growing set of evidence that the Late Cretaceous period was not dominated by large or giant species, and that smaller pterosaurs may have been well represented in this time.  As with other evidence of smaller pterosaurs, the fossil specimen is fragmentary and poorly preserved: researchers should check collections more carefully for misidentified or ignored pterosaur material, which may enhance our picture of pterosaur diversity and disparity at this time.”

The study, which also involved researchers from the University of Portsmouth, North Carolina State University, and the University of Alberta, was funded by the Natural Sciences and Engineering Research Council of Canada.

Dr Mark Witton, as well has having a remarkable knowledge of the Pterosauria and fantastic drawing skills, has authored a number of books on the subject of flying reptiles.  In 2013, his marvellous book “Pterosaurs, Natural History, Evolution, Anatomy” was published by Princeton University Press.  We at Everything Dinosaur recommend this book, not only for those with an academic interest but also for the general reader.

To read a review of “Pterosaurs” by Dr Mark Witton: “Pterosaurs” – A Book Review.

Everything Dinosaur acknowledges the help and support of the University of Southampton in the compilation of this article.

Visit Everything Dinosaur’s website: Everything Dinosaur.

Microleo attenboroughi – Pocket Marsupial Lion Honours Naturalist

Naturalist Sir David Attenborough has had yet another prehistoric critter named in his honour.  This time, it’s a kitten-sized marsupial lion, a member of the fearsome Thylacoleonidae family.  Sir David has been a long time supporter of the Riversleigh World Heritage site of north-western Queensland (Australia), and it is from these freshwater limestone deposits that fossils representing a new type of marsupial lion were excavated.

Microleo attenboroughi – A Fearsome “Kitty”

Microleo attenboroughi – a tiny, arboreal Marsupial Lion.

Picture credit: Peter Schouten

Microleo attenboroughi

Microleo attenboroughi (Attenborough’s tiny lion) was very probably arboreal and it shared the lush, tropical forests of the Miocene of Australia with a number of other types of marsupial lion.  None of them were anywhere near as big as Thylacoleo carnifex of the Pleistocene and despite the extremely fossiliferous nature of the site, only one specimen, represented by some skull fragments and parts of the jaw, of Microleo has been found to date.  Microleo is the smallest member of the Thylacoleonidae known to science.

Commenting on the discovery, Dr Anna Gillespie of the University of New South Wales stated:

“Microleo attenboroughi would have been more like the cute but still feisty kitten of the family.  It was not lion-size or even bob-cat-size.  Weighing only about 600 grams, it was more like a ringtail possum in size.”

A spokesperson from Everything Dinosaur commented that the newly described marsupial lion would have weighed less than an average pet guinea pig.

University of New South Wales Field Team Members Looking for Fossils

The fossil rich part of the Riversleigh deposits where the Marsupial Lion fossil discovery was made.

Picture credit: University of New South Wales

Visiting Neville’s Garden

The fossil was found in a location at Riversleigh known as Neville’s Garden, which has become renowned for its rich diversity of animals.  The new species has been described in the academic journal “Palaeontologia Electronica”.  Although only fragmentary fossils were found, the maxilla contain an enlarged, shearing premolar tooth in front of the other molars, a specialised feature characteristic of the marsupial lion family.  The fossils are believed to be between 18-19 million years old.

The Teeth of M. attenboroughi Compared to Thylacoleo carnifex

The relatively tiny tooth row of Microleo attenboroughi (top), compared with the tooth row of its Pleistocene relative, the lion-sized Thylacoleo carnifex.

Picture credit: University of New South Wales

The Famous Riversleigh Site

The diversity of marsupial lion fossils from Riversleigh is unparalleled anywhere else in Australia.  Despite its small size M. attenboroughi was one of the larger mammalian carnivores known from the limestone deposits.  The ancient rainforest environment was certainly extremely rich, although very little evidence regarding the flora has been preserved, the Riversleigh deposits have revealed fossils of tiny koalas, toothed platypuses, possums, kangaroos, reptiles, bats and all sorts of different birds including Australia’s earliest known parrot.

For models and replicas of prehistoric animals: CollectA Deluxe Prehistoric Animal Figures.

Commenting on the diversity of species present, Dr Gillespie said:

“Microleo shared these northern Miocene rainforests with two larger species of marsupial lion, one cat-sized and the other dog-sized.  Although it is possible they competed with one other, the size differences probably means they each specialised on a different size range of prey.  It’s likely that Microleo scampered amongst the tree-tops, gobbling insects as well as small vertebrates such as lizards and birds while simultaneously trying to avoid becoming a prey item for its larger relatives.”

The Holotype Fossils of Microleo attenboroughi

The right maxilla and the left maxilla of Microleo attenboroughi with line drawing illustrations (occlusal views).

Picture credit: University of New South Wales

Analysing the Fossil Teeth and Jaws

The picture above shows (1) a dorsal view of the right maxilla and a dorsal view of the left maxilla (2).  When examining dentition the dorsal view is often referred to as the occlusal view (the view from the top looking down at the biting surface of the teeth).  The two line drawings (3) and (4) are illustrations of the right and left maxillas respectively.    Picture (5) is a view of molar 3.

Key: aabc, accessory anterobuccal cusp; ac, anterior cusp; lb, longitudinal blade; mcl, metaconule; mcus, medial cusp; me, metacone; pa, paracone; pc, posterior cusp; pr, protocone.

The researchers hope that more fossil material of Microleo can be found.  This would help them work out more about the anatomy of this tiny predator, such as whether or not Microleo possessed an enlarged “killing thumb claw”, like its relative Thylacoleo.

To read a recently published article examining how Thylacoleo carnifex may have hunted: How the Marsupial Lion Got To Grips With Its Prey.

New Specimen of Archaeopteryx Goes on Display

In February 2014, it was announced that a twelfth specimen of the iconic Late Jurassic “dino-bird” Archaeopteryx had been discovered.  A private fossil collector was exploring a quarry near the Schamhaupten district of southern Germany (Bavaria), when a slab containing the bones of a vertebrate were unearthed.  The specimen was spread over several, fragmented pieces but its significance was quickly realised and experts brought in to prepare the fossil with professionalism and care.  This week, after several years of preparation the specimen has gone on display.

The Newest (and Oldest) Archaeopteryx Fossil

About to go on display the oldest Archaeopteryx specimen known.

Picture credit: Associated Press

The fossil finder did everything correctly, filing the discovery at the district office that manages the quarry.  With the specimen logged, palaeontologists were able to set about preparing the delicate fossils (which were softer than the surrounding finely grained limestone), so that the all the details that had been preserved could be revealed.

The Twelfth Archaeopteryx Specimen

Although all the fossils of this iconic Late Jurassic animal derive from the Solnhofen area of southern Germany, the twelfth specimen, the newest, is also the oldest.  The strata in which this fossil was found is at least 200,000 years, possibly as much as 300,000 years, older than the rocks in which other Archaeopteryx remains have been found.

For much of the Late Jurassic, western Europe was covered by a shallow tropical sea.  Small islands formed an archipelago which stretched from Portugal to France and into Germany and where the land met the water there were extensive lagoons.  Some of these lagoons became cut off from the sea and also from terrestrial runoff.  They remained relatively still bodies of water that gradually became more saline and anoxic (low in oxygen).  These conditions meant that there were few large organisms around to scavenge any carcases should they end up in the water.

The lack of current enabled the bodies of organisms to gently become covered by the soft carbonate mud.  This led to the fantastic degree of preservation seen in many of the Solnhofen fossils found today.

A Closer View of the Archaeopteryx Specimen (Note the Ammonite Fossil)

Pointing out the details on the Archaeopteryx fossil.

Picture credit: Associated Press

The Oldest Archaeopteryx Specimen

The picture above shows a close up view of the twelfth Archaeopteryx fossil specimen after it has been prepared.  The finger in the photograph is hovering just above the long tail.  Over the skull of the Archaeopteryx, the flattened fossilised remains of an ammonite can be clearly seen.  The ammonite fossil has helped to date the specimen to around 153 million years ago.  Palaeontologists have proposed that the presence of the ammonite suggests that the Archaeopteryx was washed out into the lagoon, perhaps in a storm, after which, it and the corpses of other animals unfortunate to have been caught out in the bad weather came to rest.

An Illustration of Archaeopteryx (A. lithographica)

At Everything Dinosaur an Archaeopteryx model.

Picture credit: Everything Dinosaur

The picture above shows an interpretation of Archaeopteryx, a model made by Safari Ltd and introduced in 2015, this replica is part of the Wild Safari Dinos collection, to view the models: Wild Safari Prehistoric World Figures.

The model has been given a coat of black feathers, this reflects some of the latest research into the colouration of Archaeopteryx lithographic published at the time.

To read an article that discusses the potential colour of the feathers of Archaeopteryx: Archaeopteryx “Black in Black”.

This twelfth Archaeopteryx specimen will be put on display at the new Dinosaurier-Freiluftmuseum Altmühltal in Germany.

Everything Dinosaur supplies prehistoric animal and dinosaur toys.  Visit Everything Dinosaur’s user-friendly website: Everything Dinosaur.