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The actinopterygians, or ray-finned fishes, are a substantial and significant component of modern vertebrate (animals with backbones) diversity. Ray-finned fishes are bony and have paired fins that are supported by rays (the actinosts) that insert directly in the body. Examples of modern ray-finned fishes include trout, eels, and bettas. Despite their prevalence today, the early evolution of this group is poorly understood compared to other major groups, driven by a lack of informative fossil data.

In his talk, Conrad Wilson explains how recent work on Early Carboniferous fossil sites from Nova Scotia and around the world provide new insight into the evolution of this group and how the development of the modern vertebrates may have been influenced by the mass extinction at the end of the Devonian Period (419 – 359 million years ago).

Mosasaurs were large, flipper-bearing swimming lizards from the age of the last dinosaurs, about 100–66 million years ago. Typically reaching the size of a pickup truck in length—and some nearly twice as long—over 70 mosasaur species are reported today based on the fossils collected from all over the world. Out of this highly diverse assemblage, halisaurine mosasaurs were small and seemed less well adapted to life in water since they lacked the well-developed flippers and tail fin of their larger contemporaries. Yet these small mosasaurs became increasingly more common in the fossil record towards the end of the Cretaceous, indicating their evolutionary success alongside their larger, fast-swimming cousins.

In his talk, Dr. Takuya Konishi, from the University of Cincinnati, explains why a recently discovered skull from Japan sheds new light on halisaurine mosasaurs’ potential survival strategy: that halisaurines evolved a pair of large, forward-facing eyes that would have increased their ability to see in the dark, allowing them to hunt at night.

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.

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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.

With the cold weather and the short days, it’s safe to say that most people are missing summer. For our palaeontologists though, the winter months are an important part of the research process. In summer, they go out in the field to dig up new specimens. Winter is the time for analyzing what they’ve collected, writing it up, and perhaps even publishing a paper on a new discovery. We’ve asked our palaeontologists how they spent last summer and, in this two part series, they summarize the work they accomplished.

David Eberth, Research Scientist, Sedimentary Geology and Palaeoecology

During the 2016 field season, I was able to make exciting new adjustments to the geologic time scale for Alberta. For the past 31 years, I have been involved in assessing the ages of bentonites that are associated with Alberta’s dinosaurs.  Bentonites are ancient volcanic ash and glass deposits that have been geologically altered by burial pressure and temperature after they were exploded from volcanoes. Given the mineral crystals they contain formed at the time of eruption and deposition, the tiny amounts of radioactive isotopes they contain can be analyzed to assess the age of sediments and fossils they were deposited with.

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Dry bentonite from Midland Provincial Park

Hunting for bentonites takes patience and requires lots of digging and hauling. A sample that looks good at the surface may turn out to be a bust once I dig more deeply into the rock. In the field, I examine samples with a hand lens, but samples must also be examined in much greater detail in the laboratory using a microscope. As it takes lots of effort to get to a location, I often collect a potential sample in bulk before returning to the lab. A bulk sample usually means six large zip-lock bags of rock that weigh about as much as two bowling balls.

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Collecting samples is hard work!

Over the years there have been incredible advances in the science of radioisotopic dating. When I started out studying the ages of bentonites in the late 1980s, I was limited to using potassium-argon, and argon40/argon39 dating, which provided accuracy at the level of plus-or-minus 1 million years. Such results allowed me to compare the approximate ages of dinosaur occurrences from different places around the world, but prevented me from making detailed comparisons. More recently I have turned to a revolutionary new technique called uranium lead chemical abrasion thermal induction mass spectrometry (U-Pb CA-TIMS dating, for short). This technique uses zircon crystals that occur in the bentonites and provides very high resolution ages for Alberta’s dinosaurs — plus-or-minus 30,000 years.  For dinosaurs that are about 70 million years old, such accuracy and resolution is phenomenal. Today’s results are more than 20 times more accurate and precise than when I began studying bentonites in the 1980s. Calibrating the age of Alberta’s dinosaurs with such high precision has had profound scientific significance on our research at the Royal Tyrrell Museum of Palaeontology; we can assess patterns of dinosaur evolution, migration, and response to changes in climate and sea-level around the world. With so much new technology available, it’s an exciting time to be studying dinosaurs!

Prior to this summer, my work with CA-TIMS has focused on recalibrating the ages of the rocks and fossils at Dinosaur Provincial Park. Today we know that the dinosaurs at the Park range in age from 76.69 million years to 74.26 million years. This past summer, I spent many hours hunting for datable bentonites in the Horseshoe Canyon Formation in the Drumheller area. Six bentonites were ultimately targeted and will be dated this year.

Dennis Braman, Research Scientist, Palynology

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Callum Creek area

While not much field work happened this summer, the main focus was trying to unravel the biostratigraphy of the vertebrate localities along the Oldman River. Biostratigraphy is the use of fossils to date rock formations – if you know approximately when a plant or animal lived from other sites, you know approximately the age of any rock that contains them. I collected samples from a tributary of the Oldman River near Callum Creek with poor results, a section along the Crowsnest River that indicated the Willow Creek Formation is younger than that exposed along the Oldman River, and a section north of Pierce, Alberta, again to try to work out the biostratigraphy as it relates to the section along the Oldman River west of the Porcupine Hills. I have also been doing in-house work trying to determine the ages of a number of other vertebrate localities with the samples provided by other researchers.

Don Brinkman, Head of Preservation and Research, and James Gardener, Curator of Palaeoherpetology

Vertebrate microfossil localities are accumulations of smaller-sized (about 5 cm and less) fossilized bones, teeth, scales, and other hard body parts from vertebrates (animals with backbones). These fossil localities typically occur in fine-grained sedimentary rocks that were deposited in ancient rivers and ponds and on adjacent, low lying areas such as floodplains. The preserved fossils generally represent a mixture of aquatic, semi-aquatic, and terrestrial animals that lived within a localized area and during a restricted interval of time (tens to hundreds of years).  Although the fossils themselves are small, animals of different body sizes are routinely represented. For example, tiny jaws and vertebrae from small animals, such as frogs and minnow-sized fish, may be preserved along with thumb-sized teeth and toe bones from large dinosaurs.

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A salamander vertebra in situ

Fossils from vertebrate microfossil localities are important for providing information about the different kinds of animals represented at the localities and insights into ancient ecosystems. In fact, much of what we know about smaller- and medium-sized animals (less than 75 kilograms) during the last 15 million years of the Late Cretaceous in Alberta is founded on fossils from vertebrate microfossil localities.

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The Royal Tyrrell Museum of Palaeontology has long been interested in locating, collecting, and studying vertebrate microfossil localities (for further details on that and other research programs at the Museum, see the 2015 paper entitled “Introduction to the Special Issue commemorating the 30th anniversary of the Royal Tyrrell Museum of Palaeontology, with a summary of the Museum’s early history and its research contributions,” available for free download). A region of particular focus for the Museum has been the richly fossiliferous Dinosaur Provincial Park in southern Alberta. There, several dozens of vertebrate microfossil localities have been identified through an 85 metre sequence of rocks that spans about two million years of time during the latter part of the Late Cretaceous.

During the 2016 field season, Drs. Don Brinkman and Jim Gardner re-located and photo documented 20 vertebrate microfossil localities in Dinosaur Provincial Park. This survey was a first step in preparing to re-sample and study selected vertebrate microfossil localities of interest to their respective research agendas.

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Dr. Don Brinkman poses at one of the sites

At the end of the 2016 field season, Museum staff sampled the new eggshell locality. This locality is interesting because it preserves abundant and well-preserved bones of teleost fish and amphibians, groups of particular interest to Brinkman and Gardner, respectively.  It also was the first vertebrate microfossil locality that Brinkman found when he began his work in 1985. Nearly 600 kilograms of fossiliferous matrix were collected from the new eggshell locality and transported to the Royal Tyrrell Museum of Palaeontology. Over the winter, the matrix will be washed through fine screens to recover the fossils.  We look forward to seeing what treasures might be revealed.

Join us for part two of this series, where we share what our mammologist and dinosaur palaeontologists were up to last summer!

The extinction of mammoths is the most prominent of Late Pleistocene extinctions that wiped out nearly 70% of large mammals (megafauna) from western Europe through South America about 10,000 years ago. However, on small islands off the coast of Alaska and Siberia, populations of mammoths persisted for many thousands of years after mainland populations disappeared.

In his talk, Dr. Duane Froese from the University of Alberta presents new research on the extinction of mammoths and other megafauna from Arctic North America and the causes of the final extinction of a population on St. Paul Island, Alaska, about 6000 years ago.

Congratulations to the Royal Tyrrell Museum’s Palaeoichthyology Research Assistant, Dr. Julien Divay. A paper which he coauthored is one of publishing company Elsevier’s top five most cited articles from the journal Cretaceous Research for the past three years. Why is this? Dr. Divay explains:

The article describes dinosaur ichnoassemblages (assemblages of trace fossils, in this case footprints and track ways) from the late Early Cretaceous of southern Shandong Province, in eastern China. In recent years, China has been investing money into the preservation and study of its geological/palaeontological heritage, by creating geoparks (China has 200 now, compared to Canada’s two parks, Stonehammer and Tumbler Ridge, and Tumbler Ridge was only recognised since the publication of our article), and inviting international researchers to work on them. That is how I was invited to tour multiple localities throughout China in 2012, including the Shandong sites, and to publish on these as part of an international collaboration led by Dr. Lida Xing (then a Ph.D. student and now a professor at China University of Geosciences, Beijing campus). We also took the opportunity to publish on a fish from Chongqing around the time I started at the Royal Tyrrell Museum in spring of 2015.

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Eight of the ten authors (from left): Julien Divay, Richard McCrea and Lisa Buckley (Peace Region Palaeontology Research Centre, BC), Lida Xing (CUG, Beijing), Martin Lockley (University of Colorado, Denver), Qingzi Wu (Land and Resources Bureau, Shandong), Hendrik Klein (Saurierwelt Paläontologisches Museum, Neumarkt, Germany), Daniel Marty (Office de la culture, Paléontologie A16, Switzerland), and Yonggang Tang (palaeoartist).

The Cretaceous Research article “Diverse dinosaur ichnoassemblages from the Lower Cretaceous Dasheng Group in the Yishu fault zone, Shandong Province, China,” published in 2013, is co-authored by ten people based in China, the U.S., Switzerland, Germany, Poland, and Canada. I suspect that its popularity is based on three factors:

  • It is part of this push to publish the previously undocumented palaeo heritage of China, meaning that all of these new articles coming out in recent years are quite popular in China, and have a tendency to cite one another. This is likely all the more true for dinosaur tracks articles, since these were mostly ignored in China up until just a few years ago, and are now worked on by a relatively small group of people. In fact, the trip ended with the holding of the first Chinese Dinosaur Tracks Symposium in Qijiang with pretty much all of us.
  • The assemblages of Shandong are diverse, with at least two different groups of theropods, at least two different groups of sauropods differentiated by morphology and posture, and a mysterious tetradactyl (four-toed) track way that we tentatively (but, I think, reliably) attribute to a psittacosaur.
  • One of the theropod track ways is didactyl (two-toed), which is quite rare. This also gets a lot of attention, since it represents a deinonychosaurian (colloquially: a medium-sized raptor) track, and these tend to be crowd-pleasers
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Some of the didactyl tracks.

Dragon; fossil

Comments Divay: “One of my favourite pictures: As I went prospecting for more tracks around one of the localities, I found this statue of a pacing dragon, immediately above the didactyl track way (Lida and the crane we were using are visible at the bottom of the hill, to the right). 2012 was a year of the dragon, too, by the way.”

The paper is available in Cretaceous Research 45 (2013).

Dinosaur Provincial Park received a special pair of visitors in August: Drs. Pan Conrad and Dina Bower of the Planetary Environments Laboratory at the NASA Goddard Space Flight Center in Maryland. Dr. Conrad is an astrobiologist and mineralogist. She studies both minerals and extraterrestrial life. Dr. Bower is a palaeobiologist and geobiologist—she studies microbes from the beginning of life on Earth. Both are involved in the search for proof of prehistoric life on Mars.

Mars and Earth formed at the same time but look radically different now. It’s unclear if this is merely because of their respective locations (Earth is in a sweet spot, Mars not so much) or because Mars was damaged in some way. About four million years after the planets were formed, asteroids shot through the solar system and Mars may have been hit so badly that the planet re-melted. We do know that its magnetic field was lost, which means the planet has no protection against deadly radiation, both background radiation and from the sun.

full_marsWhy does this matter? These deadly radioactive particles are able to strip away a planet’s atmosphere. It’s possible that life emerged at the same time on both Earth and Mars (either concurrently or one seeded the other—yes, there is a possibility that all life on Earth is technically extraterrestrial); however, life on Mars was thwarted. While there are no signs of life on the surface of Mars, there may be evidence beneath the surface. As there are a lot of rocks on Mars, the challenge is figuring out which ones may hold the fossils of early life.

We know roughly when life emerged on Earth, so the best place to start looking is in rocks that are the same age, but dating rocks on Mars is tricky. On Earth, we need to know the mass of a sample in order to accurately date it. As there is currently no way to bring samples back from Mars, how can we get samples to analyze?

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