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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.

Montanoolithus_04_201409181406_1800

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.

 

In June of 2015, the Royal Tyrrell Museum of Palaeontology revealed a new species of horned dinosaur named Regaliceratops peterhewsi, meaning ‘royal horned face,’ a discovery that turned out to be one of the most exciting dinosaur stories of 2015. The dinosaur, a member of the Ceratopsidae family, is notably different from other known relatives in both the size and shape of the horns on its face and a distinctive, crown-like frill at the back of its skull. The beaked, herbivorous dinosaur dates from the Cretaceous Period, a time that saw the highest diversity of ceratopsian dinosaurs. Nicknamed “Hellboy” due to the combination of difficult excavation conditions and hardness of the rock surrounding the skull, this specimen has provided exciting new information about the evolution of horned dinosaurs.

This talk highlights the story behind the discovery and preparation of the skull and illustrates the process involved with the description and naming of this new species. The talk also shows why the horns and frill of this new animal were so surprising, and what this means for the pattern of evolution of the horns and frill in the Ceratopsidae.

The Royal Tyrrell Museum’s Speaker Series talks are free and open to the public. The series will be held every Thursday until April 30, 2015 at 11:00 a.m. in the Museum auditorium.

Speaker Series 2016: “Over the Heads of Dinosaurs – Pterosaurs!”

Pterosaurs (“winged reptiles”) appeared at the same time as the first dinosaurs, about 230 million years ago, and went extinct with the last of the dinosaurs 66 million years ago. Pterosaurs first appear in the fossil record as fully-evolved, specialized, flying animals, so their evolutionary origins are still a bit of a mystery. They ranged from the size of a sparrow all the way up to the largest flying animals known with wingspans of 10-12 metres. They were the first backboned animals to evolve active, powered, flapping flight, and did so many tens of millions of years before birds, and 170 million years before bats. Pterosaurs have been known for over 215 years (longer than for dinosaurs), but their skeletons are very delicate and their fossils are extremely rare. Most of what we know about pterosaurs comes from just a few sites scattered across the world where exceptional preservation of many individuals, soft-tissues such as skin and “fuzz,” or  three-dimensional skeletons give us detailed views of just a  few hundreds of thousands of years out of the 160 million years that pterosaurs lived.

This presentation by the Museum’s own Dr. Donald Henderson, Curator of Dinosaurs, introduces pterosaurs and highlights many of their exceptional fossils that have been found in the past twenty years, and explains how our understanding of these mysterious animals has dramatically improved over this short time.

 

Chas_frog

Frogs are the most familiar of living amphibians. Adults are distinctive; having a squat body, no tail, and powerful hind limbs. They also are entirely carnivorous, typically eating insects and other small invertebrates, although larger frogs will also consume bigger prey such as snakes, rodents, and even other frogs. Most frogs begin life in fresh water, where their gelatinous eggs hatch into a fully aquatic and herbivorous larval form called a “tadpole.” The tadpole feeds, grows, and eventually undergoes a dramatic metamorphosis that culminates in it changing into the adult form. Although frogs are constrained by being cold-blooded and having skin that can dry out, they are the most diverse and widespread of living amphibians. Today over 6,550 living species are found on most continents, except Antarctica. They occur in a variety of ecosystems including temperate forests, semi-arid grasslands, and lush tropical forests. Some frogs are fully aquatic, whereas others live in trees, alongside the margins of ponds and streams, or in burrows.

The fossil record of frogs extends back to the earliest Triassic (about 240 million years ago) alongside the earliest appearances of dinosaurs and mammals. Some spectacular frog fossils are known, including tadpoles in various stages of development and complete skeletons of adult frogs; however, the most common frog fossils are isolated bones. Thanks to the distinctive structure of the frog skeleton, most of their bones are easily identifiable and can be informative for identifying species.

In Alberta, vertebrate microfossil localities, which are accumulations of small fossil bones, teeth, and scales from many kinds of vertebrate species, are a rich source of frog bones from the latter part of the Late Cretaceous (about 85 to 65 million years ago). Frog fossils have been known in Alberta since the mid-1960s. The accumulation of specimens and research over the past fifty years from isolated bones collected from those microfossil localities, led Museum researchers to formally describe two new species of Late Cretaceous frogs earlier this year. These are the first fossil frogs to be named from Alberta.

The first species, named Hensonbatrachus kermiti in honour of the muppeteer Jim Henson and his Kermit the Frog™ muppet, was described by Dr. Jim Gardner, Curator of Palaeoherpetology, and Dr. Donald Brinkman, Director of Preservation and Research. Hensonbatrachus is known from skull bones, ilia, and a humerus. It was a moderate-sized frog, with an estimated body length of 75 to 115 mm. The external surfaces of its skull bones are ornamented with bony ridges and its upper jaws bore many small teeth.

The second species was described by Dr. Jim Gardner and was named Tyrrellbatrachus brinkmani in honour of the 30th anniversary of the Royal Tyrrell Museum of Palaeontology and Dr. Donald Brinkman, one of the founding researchers at the Museum. Tyrrellbatrachus is known only by a half dozen upper jaws, distinctive because they are considerably smaller, have a nearly smooth external surface, and are entirely toothless. Loss of teeth is a common feature among frogs and its occurrence in Tyrrellbatrachus represents one of the oldest (about 76. 5 million years ago) instances of this phenomenon. The presence of additional frog bones in the same localities that yielded these two new frogs indicates that a number of different frog species lived alongside dinosaurs during the Late Cretaceous of Alberta.

RTMP blog_fossil frogs_fossil jaws figure_Jim ver_2015-11-27

Incomplete upper jaws (maxillae) of two new species of fossil frogs from the Late Cretaceous (ca. 76.5 million years ago) of Alberta, described this year by researchers at the Royal Tyrrell Museum of Palaeontology: Hensonbatrachus kermiti (top: specimen number UALVP 40167, holotype) and Tyrrellbatrachus brinkmani (bottom: specimen number TMP 1985.066.0035, holotype). Both specimens are shown at same sizes for ease of comparison; the smaller image of the Tyrrellbatrachus maxilla at left shows its actual size compared to the much larger Hensonbatrachus maxilla. The Hensonbatrachus fossil is courtesy of the University of Alberta Laboratory for Vertebrate Paleontology.

References:

Gardner, J.D. 2015. An edentulous frog (Lissamphibia; Anura) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of southeastern Alberta, Canada. Canadian Journal of Earth Sciences, 52: 569–580.

Gardner, J. D., and Brinkman, D.B. 2015. A new frog (Lissamphibia, Anura) from the Late Cretaceous of Alberta, Canada. In: All Animals are Interesting: a Festschrift in Honour of Anthony P. Russell. Edited by: O.R.P. Bininda-Emonds, G.L. Powell, H.A. Jamniczky, A.M. Bauer, and J. Theodor. BIS Verlag, Oldenberg, pp. 35–105.

Illustration by © JULIUS T. CSOTONYI

Illustration by © JULIUS T. CSOTONYI

A new paper published this month in PeerJ biological and medical sciences journal describes a specimen of the small pterosaur (flying reptile) Rhamphorhynchus. The specimen is noteworthy due to the spectacular preservation of soft tissue, stomach contents, and what’s considered to be coprolite (fossilized poop).

Research featured in the journal was the collaborative effort of Drs. David Hone (Queen Mary University of London), Donald M. Henderson and François Therrien (Royal Tyrrell Museum of Palaeontology) and Michael B. Habib (Natural History Museum of Los Angeles).

Numerous pterosaur specimens had been found previously, preserving fish remains in their gut, indicating these animals lived near water bodies and fed on fishes.  This particular Rhamphorhynchus specimen is the first to preserve the remains of a fish, shark, and potential tetrapod (i.e., a four-legged animal) in its stomach, and a coprolite filled with strange hooklets. Although the identities of the material preserved in the stomach and coprolite could not be determined, they reveal that Rhamphorhynchus did not feed exclusively on fish. This spectacular specimen gives researchers unique insight into dietary and ecological traits of this small Late Jurassic pterosaur.

The specimen is housed at the Royal Tyrrell Museum of Palaeontology in Midland Provincial Park, Alberta.

Rhamphorhynchus

To commemorate the 30th anniversary of the Royal Tyrrell Museum of Palaeontology and its contribution to scientific research, the Canadian Journal of Earth Sciences released a special edition in August. Included in this special volume is the paper Marine Turtles from the Late Cretaceous of Alberta, Canada, a result of collaborative research with renowned scientists including Donald Brinkman, Royal Tyrrell Museum; Michael Densmore, Harvard School of Dental Medicine; Márton Rabi, University of Tubingen, Institut für Geowissenschaften; Michael Ryan, Cleveland Museum of Natural History; and David Evans, Royal Ontario Museum and University of Toronto.

Cheloniid turtles from the Late Cretaceous of Alberta are described in this paper. Members of this group of marine turtles, that includes the living green turtle, are thought to have originated in the Western Interior Seaway that covered the interior of North America 130-70 million years ago. Although this group is well known from localities in Kansas and Alabama, only a few specimens are known from Alberta.

At least two kinds are present, one previously new and one described in this paper. The new turtle is represented by two dentaries (lower jaws), one of which was found by the Southern Alberta Dinosaur Project group. Although known only from a lower jaw, this turtle is distinctive and was described as a new genus and species.The holotype specimen Kimurachelys slobodae was discovered by Wendy Sloboda during the Southern Alberta Dinosaur Project, which has discovered and described more than a dozen new dinosaurs and turtles from Alberta in the past decade,” said Dr. Michael Ryan, Curator of Vertebrate Paleontology, Cleveland Museum of Natural History. The generic name, Kimurachelys, honours Marilyn Kimura, who has made significant contributions to the preservation of Alberta’s fossils and the specific name slobodae honours the discoverer.

The marine turtles described in this paper provide new insights into the early evolution of cheloniid turtles. “The specimens are about 75-73 million years old, which is younger than the well-known marine turtle assemblages from Kansas, Alabama, and South Dakota. This assemblage fills in a gap in the record of marine turtles from North America,” says Dr. Donald Brinkman. There is evidence that the marine turtles from this time are distinctly more advanced than the ones from Kansas and South Dakota. Other groups, particularly mosasaurs and fishes, also show a faunal shift. This demonstrates that there was some kind of change in community structure at about this time; however, further research is needed to determine what this change was.

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