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Alberta is a great place for a dinosaur palaeontologist, with plenty of preserved skeletons and some of the best evidence for dinosaurs in the world.

However, in the Willow Creek Formation of southwestern Alberta, which records the last few million years before the extinction of dinosaurs, only three kinds of dinosaur skeletons have been found: Tyrannosaurus rex, an undetermined hadrosaur (duck-billed dinosaur), and an undetermined leptoceratopsid (small horned dinosaur). Were those the only dinosaurs living here during that time? Unlikely, but how do we know what dinosaurs were present if their skeletons weren’t preserved?

Unlike many geological formations in Alberta, dinosaur eggshells are quite common in the Willow Creek Formation. The ancient soils (a.k.a. paleosols) present in the formation suggest that conditions were arid to semi-arid at the time, which led to excellent preservation of dinosaur eggshell. Like skeletons, eggshells tend to be distinctive between the various kinds of dinosaurs and can be used to identify what dinosaurs were present.

A new scientific article by our Curator of Dinosaur Palaeoecology, François Therrien, in collaboration with Darla K. Zelenitsky, Kohei Tanaka, Philip J. Currie, and Christopher L. DeBuhr, presents an analysis of eggshells discovered in the Willow Creek Formation. The team inspected hundreds of dinosaur eggshells recovered from several sites in southwestern Alberta. They were able to determine that the eggshell fragments were produced by at least seven different types of dinosaurs: two ornithopods (a group of bipedal, herbivorous dinosaurs, including hadrosaurs) and five small theropods, including oviraptorosaurs, troodontids, and dromaeosaurs (colloquially, raptors). Because researchers frequently cannot correlate an eggshell with a specific species unless it is associated with a parent or a baby inside the egg, eggshells are given their own species names, in parallel to the way skeletons are named. These are called ootaxa.


Montanoolithus eggshell, belonging to a small theropod, was discovered in southwestern Alberta. Art by Julius T. Csotonyi.

This research triples the known dinosaur diversity of the Willow Creek Formation, from three species based on skeletons only, to at least nine known from skeletons and eggshells. In addition, it extends the known temporal range of some of the ootaxa to 10 million years and gives a better sense of the ancient ecosystem in southwestern Alberta at the end of the Age of the Dinosaurs.

The article, titled “Latest Cretaceous eggshell assemblage from the Willow Creek Formation (upper Maastrichtian – lower Paleocene) of Alberta, Canada, reveals higher dinosaur diversity than represented by skeletal remains,” was published in the January 2017 issue of the Canadian Journal of Earth Science.

One of the most exciting things about the Royal Tyrrell Museum is that it’s more than a Museum, it’s an active research facility, so there are exciting things happening all the time that further our understanding of ancient life.

Dr. James Gardner, our Curator of Palaeoherpetology (the study of prehistoric reptiles and amphibians), has just published a paper on fossil tadpoles in a special issue of the journal Fossil Imprint, available for free here.

Scientific research papers often owe their origins to chance events and may take years to come to fruition. Such is the case for “The Fossil Record of Tadpoles.” Dr. Gardner’s interest in fossil tadpoles was sparked in the early 1990s, when he recognized a 45 million year old tadpole fossil in the University of Florida Museum of Natural History’s fossil plant collection. He began working on a manuscript reviewing the fossil record of all tadpoles but it was set aside for decades, as he became busy with other projects – his PhD dissertation, for example. Fast forward a quarter century later, when Dr. Gardner was invited to contribute a paper to a volume commemorating the Czech palaeontologist Zdeněk Špinar (1916–1995). Knowing that Professor Špinar had published many papers on fossil tadpoles, Dr. Gardner decided to resurrect and update his dusty and almost forgotten manuscript.

One of the most characteristic features of anurans (frogs and toads) is their two-stage or biphasic life cycle consisting of a free swimming, vaguely fish-like, and typically herbivorous larval form (tadpole) that undergoes profound and rapid structural remodeling (metamorphosis) to become a four-legged, hopping, and exclusively carnivorous adult.



Metamorphosis of tadpole into frog. Source.


Metamorphosed or adult frogs are moderately well represented in the fossil record; but many people are surprised that tadpoles also appear. At first glance, tadpoles seem poor candidates for fossilization: they are small, have only a rudimentary skeleton, and the tadpole phase of a frog’s life cycle generally lasts only a few months.

However, lakes provide an ideal environment for preserving those kinds of fossils, thanks to the fine-grained sediments in lake bottoms that can quickly cover and preserve carcasses. They are also ideal habitats for tadpoles.


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Figure 1: An indeterminate tadpole body fossil from the middle Eocene (approximately 45 million years ago) of Utah, USA. Head points towards top of figure and scale bar along left side is in 1 mm increments. Note the characteristic tadpole body form, consisting of a globular head + body and an elongate, narrow tail. This specimen lacks any indication of a skeleton; either the individual died at a young stage before the bones began ossifying or bones were present but did not preserve. Note the preserved eye pigments, brain, and digestive tract. This fossil is in the collections of the University of Florida Museum of Natural History, Gainesville, Florida.


Dr. Gardner’s review showed that the fossil record of tadpoles is better than most people realize. Tadpole body fossils have been known since the early 1800s, but in an interesting historical quirk, the first examples reported in 1828 were not recognized as tadpoles. It took another three years before tadpole fossils which were identified as tadpoles were published. Since then, fossil tadpoles have been reported from over 40 localities on most continents, except Antarctica and Australia. Those localities are in lake-style deposits and range in age from the Early Cretaceous to late Miocene (140–10 million years ago). A number of those localities have yielded multiple examples of different-sized tadpole body fossils, some so well preserved that their body outlines and details of internal structures like nerves and blood vessels can be seen.


Fossil tadpole blog_fig 2_2016-08-22

Figure 2. Examples of fossil tadpoles preserving bones and at different growth stages, both with their head pointing towards top of figure. Left: Pre-metamorphic tadpole of Shomronella jordanica (basal Pipimorpha) from the Early Cretaceous (about 130 million years ago) of northern Israel or Palestinian West Bank. This locality has yielded over 250 tadpoles of Shomronella. Right: Later stage tadpole undergoing metamorphosis of Palaeobatrachus vicentinus (Palaeobatrachidae) from the middle or late Oligocene (about 28 million years ago) of northeastern Italy. This is the only fossil tadpole known from the locality. The Shomronella fossil is in the collections of Hebrew University, Jerusalem, Israel and the Palaeobatrachus fossil is in the collections of Paläontologisches Museum, Humboldt University, Berlin, Germany; both photographs are courtesy of Prof. Zbyněk Roček (Prague, Czech Republic).


Size series of tadpole fossils from the same species are especially valuable because they provide large enough samples for palaeontologists to trace patterns of growth and metamorphosis in fossil frogs (the human equivalent would be having examples of everything from a baby to a teenager). The tadpole fossil record demonstrates that the distinctive tadpole body form and lifestyle and its astounding metamorphosis into a four-legged and hopping adult are ancient attributes of frogs.

This fish-like larval form can appear similar to other animals, such as fish and insects. In addition to reviewing the fossil record of tadpole body fossils, Dr. Gardner also examined reports of other fossils that have been interpreted as tadpoles. Those include 385 million year old larval fish fossils from the Middle Devonian of Scotland, a recently metamorphosed and 250 million year old skeleton of a proto-frog from the Early Triassic of Madagascar, and a piece of 20 million year old amber from the Dominican Republic containing what may be a tadpole hatching from an egg. Dr. Gardner provided the evidence against interpreting most of these fossils as tadpoles, although some, such as the Dominican amber, are ambiguous.

This paper and a second paper by Dr. Gardner on North American frogs from the Campanian titled “The Hopping Dead” (proof that scientists have a sense of humour) are available here. Fossil Imprint is an open access journal.

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At the Royal Tyrrell Museum, we are equal parts excited and nervous because we just launched our first large-scale exhibit in over five years. The exhibit, Foundations, is about everything that is important to us as a science and natural history museum, from the very beginnings of planet Earth, to the evolution of life, to fossils and their journey from living beings and into our Museum collections. With its expansive scope and mix of specimens, hands-on activities, and technology, Foundations is another step in our continued commitment to studying and celebrating the history of life on Earth.


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How do scientists commemorate the career and accomplishments of their colleagues? Not with a party and gifts, but with a “Festschrift,” which is the publication of a special volume of scientific papers written and compiled in dedication to their colleague. Two former researchers at the Royal Tyrrell Museum of Palaeontology each have been honoured with their own Festschrifts: Philip Currie in 2001 and the late Betsy Nicholls in 2006. More recently, Royal Tyrrell Museum researchers have been organizing Festschrifts for deserving colleagues.

The newest addition is the March 2016 issue of the journal Palaeobiodiversity and Palaeoenvironments. Co-edited by Royal Tyrrell Museum researcher Jim Gardner and colleague Tomáš Přikryl (Czech Academy of Sciences and Charles University, Prague), this new Festschrift honours the Czech herpetologist Zbyněk Roček.

As summarized by the editors’ introductory article in the Festschrift, the honouree Zbyněk Roček has led an interesting life and career.

He was born soon after the end of the Second World War, in a small town in what was then Czechoslovakia. He grew up, did his schooling, and began his academic career under the communist regime that dominated all aspects of private and professional life across Eastern Europe in those grim Cold War years.

By the mid-1990s, circumstances had changed markedly: communism had collapsed across Eastern Europe, the former Czechoslovakia had peacefully split into the Czech Republic and Slovakia, and Prague (the capital of the Czech Republic and where Prof. Roček lived) once again was becoming a fashionable and vibrant European city.

For the first time in several generations, Eastern European scientists could freely interact and exchange ideas with colleagues in the West. That change resulted in a surge of new work and collaborations, which have benefited science immensely. In a manner familiar to many scientists, the way in which Prof. Roček’s academic career unfolded was due to a sequence of fortuitous events, helpful colleagues, and seized opportunities.

Originally intending to be an ornithologist (bird biologist), Zbyněk instead was encouraged to switch to herpetology (study of amphibians and reptiles), and he ultimately became a leading expert on the evolution and fossil record of frogs. During his nearly five decades long career, Prof. Roček has published numerous articles and books, taught several generations of zoologists, and continues to be an active researcher well into retirement.

Like any good Festschrift, Professor Roček’s volume reflects the breadth of his research interests. It contains nine papers about fish, amphibians, and reptiles, ranging in age from the earliest Mesozoic through to the present, and with near global coverage. Participation by a total of 23 authors, from 11 countries and at varying stages of their careers, attests to the esteem Prof. Roček has earned within the scientific community.

For the Royal Tyrrell Museum of Palaeontology, our participation in this volume continues our institution’s tradition of fostering international collaborative scientific research.

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Cover of the March 2016 issue of “Palaeobiodiversity and Palaeoenvironments” containing scientific papers honouring the Czech palaeoherpetologist Zbyněk Roček. Cover image courtesy of “Palaeobiodiversity and Palaeoenvironments,” Springer-Verlag GmbH, Heidelberg.

For a limited time (until 30 April 2016), the publisher is generously providing free access to the entire volume at:

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