In our 102nd episode, we had the pleasure of speaking with Peter May, President of Research Casting International.
Episode 102 is also about Edmontonia, a nodosaur found in the Edmonton Formation in Canada that had shoulder spikes.
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In this episode, we discuss:
- The dinosaur of the day: Edmontonia
- Named after the Edmonton Formation (now the Horseshow Canyon Formation, in Canada) where it was found
- Part of the nodosaur family
- Lived in the Late Cretaceous
- Charles Sternberg named the type species, Edmontonia longiceps, in 1928. Longiceps means “long headed” in Latin
- Charles Sternberg did not classify Edmontonia, and L.S. Russell classified it as Nodosauridae in 1930 (which has been confirmed)
- George Paterson, the teamster on an expedition Charles Sternberg led, found Edmontonia longiceps in 1924 (on that expedition). He found a skull, lower right jaw and a lot of the postcranial skeleton, including the armor
- Barnum Brown found Edmontonia rugosidens in 1915 in Alberta, Canada, and sent it to the American Museum of Natural History (though it wasn’t yet named). William Diller Matthew referred the specimen to Palaeoscincus in 1922 in a popular science article, without naming the species. It was supposed to name a new species, in conjnction with Brown, but the article wasn’t published. Matthew also referred another specimen found by Levi Sternberg in 1917. Then in 1930 Charles Gilmore referred both of these specimens to Palaeoscincus rugosidens, based on a type speciment found in 1928 by George Fryer Sternberg. The species name means “rough tooth.” In 1940 Lori Shano Russell referred all three specimens to Edmontonia rugosidens
- Two main Edmontonia species: type species Edmontonia longiceps, and Edmontonia rugosidens (which had its own genus for a while, Chassternbergia, named by Bob Bakker as a subgenus in 1988 based on living before Edmontonia longiceps and have a different skull proportion. Then George Olshevsky gave it the full generic name in 1991. The name honors Charles “Chas” Sternberg though this subgenus/genus name is rarely applied. Later finds have been referred to Edmontonia rugosidens)
- In 1971 Walter Preston Coombs Jr. renamed the two main Edmontonia specia to Panoplosaurus longiceps and Panoplosaurus rudosidens but the name Edmontonia was later revived
- Other species: Edmontonia schlessmani (originally Denversaurus schlessmani until 1992), Edmontonia australis (named in 2000 by Tracy Lee Ford) though now considered to be a junior synonym of Glyptodontopelta mimus
- Gregory Paul suggested in 2010 that Edmontonia rugosidens was a direct ancestor of Edmontonia longiceps, which was a direct ancestor of Edmontonia schlessmani
- Bulky and like a tank. About 22 ft (6.6 m) long, though Gregory Paul estimated in 2010 that two of the Edmontonia species, Edmontonia longiceps and Edmontonia rugosidens, were about 20 ft (6 m) long and weighed 3 tons
- Had a pear like shaped skull (when viewed from above)
- Body had many osteoderms
- Plates protected its neck and shoulders
- Had small bony plates on its back and head and sharp spikes along its sides. Four largest spikes were on its shoulders. In Edmontonia rugosidens, the second set of spikes on its shoulders split into subspines
- Edmontonia longiceps spikes were relatively small, size of spikes varied in Edmontonia rugosidens
- Shoulder spikes had solid bases
- Probably had large spikes to attract mates or defend territory, also to intimidate rivals or predators or for self defense
- Shoulder spikes wouldn’t have been great defense, since they only covered the shoulders (probably not great against large theropods liks Albertosaurus and Dapletosaurus)
- Spikes could have been like horns, where Edmontonia locked them to show dominance
- Kenneth Carpenter described traits of Edmontonia in 1990, by comparing it with close relative Panoplosaurus (snout had parallel sides, skull armor was smooth on the surface, had shorter neural arches and neural spines than Panoplosaurus)
- Carpenter also showed how two of the Edmontonia species were different. Edmontonia rugosidens did not have sideways projecting osteoderms behind its eye sockets, and Edmontonia longiceps did not have an ossified cheek plate
- Skull was up to 1.6 ft (0.5 m) long and elongated, with a horny upper beak
- Had a “paranasal” tract that ran along the outside of the nasal cavity (first time found in a nodosaurid, but not an ankylosaurid, which had more complex air tracts
- May have stayed low to the ground to prevent predators from flipping them over and attacking their underbelly
- Did not have a tail club (like ankylosaurids) and had a narrower mouth than ankylosaurids
- Edmontonia appeared in “Dinosaurs: Unextinct” at the L.A. Zoo,” a new exhibit that opens April 15 and runs through Oct. 31.
- Also at the LA County Fair this year (ended in Sept)
- Also part of an exhibit at the NC Aquarium this year (ended in Sept)
- Nodosauridae is a family of ankylosaurs
- They lived in the late Jurassic to late Cretaceous in what is now North America, Europe, Asia, and Antarctica
- They were medium to large, and heavy
- Quadrupedal herbivores
- Had osteoderms on their bodies
- Fun fact: An homage to Dippy… Dippy has been on display at the Natural History Museum in London since 1905. A cast was ordered from the U.S. after King Edward the 7th saw Carnegie’s sketch of the original. In 2017 its 292 bones will be packed up and it will tour the U.K. for at least a few months.
This episode was brought to you by:
The Royal Tyrrell Museum. The Royal Tyrrell Museum is located in southern Alberta, Canada. One of the top paleontological research institutes in the world, the entire museum is dedicated to the science of paleontology. It’s definitely a must see for every dinosaur enthusiast. More information can be found at tyrrellmuseum.com.
For those who may prefer reading, see below for the full transcript of our interview with Peter May: