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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

Speaker Series 2015:  “A Year in the Life of the Royal Tyrrell Museum’s Palaeontology Lab”

With hundreds of fossils being collected every year in Alberta, the preparation laboratory of the Royal Tyrrell Museum is a busy place. As fossils are being cleaned and sent away for study or display, new discoveries constantly roll in through the doors, which mean a palaeontology technician’s work is never done.

In her presentation, Dr. Lorna O’Brien, technician with the Royal Tyrrell Museum, showcases some of the exciting fossils that have been prepared in the past year. From fossils discovered in bonebed excavations to those exposed by the 2013 floods, be ready to be amazed at the rich palaeontological resources in the Museum.

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

Preparation Lab technicians of the Royal Tyrrell Museum of Palaeontology work with fossils as they are made ready for research and display. Doing so takes great patience and care to ensure that specimens are safely handled and prepared, guaranteeing that they will reveal all they have to offer to the scientists who will soon be studying them and the public who will eventually enjoy them on display. Here is a sneak peek of a typical day in the lab.

 

Field jackets and the fossils inside them are regularly moved around the lab to accommodate changes in work assignments and to make room for priority specimens. As often is the case, the specimens are too heavy to lift by hand and the team will use the three-ton overhead hoist to safely move the specimens around the lab. Here, separate field jackets containing the rib cage portion of a Fort McMurray elasmosaur and an Oldman River Leptoceratops are rearranged to make room for additional fossils to be prepared.

Speaker Series 2015: “Money for Nothing—Three Decades of Research at the Royal Tyrrell Museum of Palaeontology”

This year marks the thirtieth anniversary of the Royal Tyrrell Museum of Palaeontology. In the January 29 edition of the 2015 Speaker Series, Dr. Jim Gardner, Curator of Palaeoherpetology, reflects on the history of the Museum and the accomplishments of its research program.

Since its opening in 1985, the Museum has become one of Alberta’s must-see tourist attractions, a significant contributor to the local economy, and one of the premier palaeontological research institutions in the world. Although the international palaeontological community is familiar with much of the scientific research that has been generated by the Museum’s scientists, many of the stories and accomplishments of the research program are less well known to the general public. Dr. Gardner walks us through how the scientific research done by staff, and by other scientists and students using the Museum’s extensive fossil collection, drives all aspects of the Museum’s activities.

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

The Collections Program at the Royal Tyrrel­l Museum is responsible for preserving the integrity of its 130,000 fossil specimens. This includes conservation of all the fossils in storage and on exhibit, which is my job—I’m Rhian Russell, the Museum’s Conservation Technician.

Conservation can be preventive in nature, such as controlling the storage environment, or interventive—stabilizing a deteriorating fossil with consolidant before it falls apart completely and cannot be saved.

We commonly use Paraloid B-72 to consolidate and adhere fossils. It’s an acrylic polymer in the form of clear beads that are dissolved in a solvent (we use acetone) to make a thin consolidant or a thick adhesive.

paraloid

Paraloid B-72 beads, and a tube containing 50% w/w Paraloid B-72 in acetone.

When applied to a fossil, the acetone slowly evaporates, and the remaining polymer holds the fossil together. Paraloid B-72 is widely used in many fields of object conservation as it has proved to be a highly reversible, stable material. These qualities are important because a fossil will only hold together as long as the glue connecting it does.

However, because Paraloid B-72 depends on the evaporation of solvent, it can take a long time to cure. This means it can be necessary to use adhesives that set faster and offer a strong bond immediately. These adhesives are usually much harder to reverse and may not be as stable as Paraloid B-72 in the long term.

Over the last couple of years, we’ve been working on a project to test the tensile strength of Paraloid B-72 compared with other adhesives that are used in fossil preparation, namely the cyanoacrylates (superglues) and epoxy resins. I want to see exactly how well B-72 performs compared to other adhesives, so that a more informed decision can be made about which adhesive to choose.

Paleobond PB100, a cyanoacrylate formulated for fossil preparation, and Devcon 2-Ton epoxy, a two-part epoxy resin.

Paleobond PB100, a cyanoacrylate formulated for fossil preparation, and Devcon 2-Ton epoxy, a two-part epoxy resin.

To test this, we worked with technicians at the Department of Mechanical Engineering at the University of Alberta using their Universal Testing Machine to pull apart test samples joined with our adhesives, and measured the exact amount of tensile force required to break the adhesive bonds. We made lots of test samples from limestone paving slab, attached aluminum tabs to the sides to connect them to the testing machine, and glued them together with Paraloid B-72, cyanoacrylate, or epoxy.

Limestone tensile test samples after testing (From Fossil Friday on the Museum’s Facebook page) https://www.facebook.com/photo.php?fbid=10150591947295172&set=a.494557285171.266761.37946265171&type=3&theater

Limestone tensile test samples after testing (From Fossil Friday on the Museum’s Facebook page

Paraloid B-72 was the weakest adhesive of the three, but it still took a great deal of tensile force to break the join.

The limestone blocks themselves broke under the same amount of tensile force as the epoxy did; meaning that many of the epoxy test samples broke in the limestone before the adhesive gave way. This is not something you want to happen to a fossil, as it means that the fossil will break somewhere new rather than at the existing break when subjected to stress. Therefore in this case, epoxy would be too strong for the material. Many of the fossils we work with would break under far less tensile force than the limestone blocks, so we don’t need to use such a strong adhesive to repair them. Paraloid B-72 should have sufficient strength for most repairs, and in my own experience, I’ve rarely found cases where it hasn’t been strong enough.

As you can see, there is much to consider when choosing materials for fossil conservation. We want specimens to last as long as possible so that they can be used for research, education, and exhibition for many generations to come.

I hope to post updates on my projects in the future, so stay tuned. If you have any questions or comments please feel free to email me.

If you would like to know more about this project, you can watch the video below:

 

– Rhian Russell, Conservation Technician

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