The Big Dinosaur Podcast

Episode 242 is all about Euoplocephalus, an ankylosaur from Dinosaur Provinical Park in Canada.

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In this episode, we discuss:

News:

• Notatesseraeraptor, a well preserved theropod of the Late Triassic was described in Switzerland source
• A new study of non-iridescent structural colors in feathers described blue feathers in an extinct bird source
• An article covered paleontologist Amy Atwater, the woman behind the Instagram account @mary_annings_revenge source
• The company Handbuilt has created a really cool augmented reality Psittacosaurus exhibit source
• The Center for Science Teaching & Learning in Rockville Centre, New York has a new dinosaur exhibit source
• A zoo in Pennsylvania has a new dinosaur exhibit, including a 65 ft long Brachiosaurus that they are crowdsourcing a name for source
• Special effects artist Tom Devlin opened a “Dinosaur Adventure” attraction in Boulder City, Nevada source
• In Washington, a group in inflatable T. rex costumes ran around a horse track source
• The film Doraemon the Movie: Nobita’s New Dinosaur is coming out in 2020 source

The dinosaur of the day: Euoplocephalus

• Ankylosaur that lived in the Late Cretaceous in what is now Canada
• About 18 ft (5.5 m) long and weighed about 2.5 tonnes
• About 7.9 ft (2.4 m) wide
• Had a flat, wide body and large gut
• Had a wide ribcage
• Quadrupedal, with short, sturdy legs
• Robust forelimbs, shorter than the hindlimbs
• Probably had a lot of muscles, based on robust bones
• Had a short neck
• Skull is triangular in shape, and is wider than it is long
• Herbivorous
• Probably not a picky eater
• Had a drooping snout and a beak to bite off plants
• Dropping snout is blunt, wide, and high
• Has 19 to 24 teeth in each upper jaw
• Lower jaw had 21 teeth
• Could pull its lower jaw backwards
• Head and body covered in bony armor of osteoderms
• Neck had two bone rings called “cervical half rings” that protected it. Victoria Arbour and others thought they formed a lower layer, may with ossified cartilage
• Cervical half ring was several bony plates fused together in an arch-shaped block
• Had bony armor plates, with rows of oval scutes
• Kenneth Carpenter described the armor in 1982, but it was based on the specimen now known as the holotype of Scolosaurus, so not exactly the same for Euoplocephalus
• Victoria Arbour said in 2013 that no Euoplocephalus specimen has in situ osteoderms, so the arrangment of osteoderms is unknown
• Armor was made of small scutes (diameter less than 5 mm), and may have formed bands (if it was the same as Scolosaurus). May have had a sacral shield, made up of four of these bands. These bands had horizontal rows of larger oval, flat scutes
• Scutes varied in size on its body. Largest, tallest scutes may have been on the shoulder, may have had large keeled plates on the upper arms
• Old restorations depicted the club with two large spikes, based on a restoration of Scolosaurus by Franz Nopsca (he based it on a specimen with an incomplete tail)
• Armor may have helped with protection and thermoregulation
• Victoria Arbour and others found an intact Euoplocephalus skull in southern Alberta, and it is at the Royal Tyrrell Museum for study
• Armor on the skull had caputegulae (head tiles) that fused with skull elements. Snout looks like a mosaic
• Had two pyramid-shaped squamosal horns that grew from the back of its head
• Also had a quadratojugal horn at the lower rear of the skull
• Also had bones over the eyes that may have helped protect them
• Had small eyes
• Had a good sense of smell, though the olfactory part of the brain was not that large
• Has two external nostrils on each side
• Had very complex air passages and sinuses
• In 2018, Jason Bourke and others found that Euoplocephalus and Panoplosaurus used CT scanning and computational fluid dynamics to simulate how air moved through their crazy nasal passages. They found that their noses could warm and cool air it breathed in (helped cool down the brain)
• Nasal passages may have moistened the air that it breathes in
• Nasal passages looked kind of like crazy straws
• The nasal passages in Euoplocephalus were almost twice as long as the skull
• The team also reconstructed blood vessels based on bony grooves and canals and found a rich blood supply running next to the nasal passage. Ruger Porter, who worked on the study, said “Hot blood from the body core would travel through these blood vessels and transfer their heat to the incoming air. Simultaneously, evaporation of moisture in the long nasal passages cooled the venous blood destined for the brain”
• Large size of Euoplocephalus was good at keeping warm, but not for cooling off (risk of overheating, espceially the brain tissue)
• Nasal passages were looped and complex, possibly for vocal resonance or to balance heat and water
• Also had a large, vascularized chamber at the back of the nasal tract, which may have helped improve its sense of smell
• Could probably hear low frequencies, possibly to hear the low sounds from the nasal passages
• Had a heavy club-like tail
• Tail was like a hammer
• Had a long tail with a bony club
• Probably held its tail just above the ground
• Probably swung the tail low (base of the tail was flexible, then the club was rigid), and may have used the club tail for defense or combat between themselves
• May have been a solitary animal
• May have mated the way cats mate, based on Kenneth Carpenter’s book in 2000 about dinosaur reproduction. He wrote that a common method “might be for the female to squat on her forelimbs, raising her rear to the air (sort of like a house cat”
• Only one species: Euoplocephalus tutus
• Lawrence Lambe found the first fossil in August 1897 in what is now Dinosaur Provincial Park, in Alberta, Canada
• In 1902 the fossil was named the holotype of Stereocephalus tutus (had part of the cranium and five scutes that were part of a cervical half ring)
• Genus name Stereocephalus means “solid head” and refers to its armor
• However, the name was already used for the beetle Stereocephalus in 1884, so the dinosaur was renamed Euoplocephalus in 1910 (means “well armed head”)
• Species name means “safely protected” in Latin
• In 1915, Edwin Hennig reclassified Euoplocephalus as Palaeoscincus, but now Palaeoscincus is consered to be a nomen dubium (only based on indeterminate ankylosaur teeth)
• In 1964, Oskar Kuhn referred Euoplocephalus to Ankylosaurus
• Lots of ankylosaurid fossils found in North America in the 1900s were named new genera. In 1971 Walter Coombs reclassified many as Euoplocephalus (he synonymized Anodontosaurus, Dyoplosaurus, and Scolosaurus with Euoplocephalus), which made 40 specimens Euoplocephalus and meant Euoplocephalus spanned about 10 million years, and the best known ankylosaurid
• In 1978 Coombs also renamed Tarchia as Euoplocephalus giganteus
• Walter Coombs and Teresa Maryanska said in 1990 that Euoplocephalus has four distinguishing traits: premaxillae doesn’t have dermal ossifications, the bony nostrils are slit-like, the beak is at least as wide as the distance between the rear maxillary, upper cheek, teeth rows, and there are three toes on each foot
• Then in 2009 scientists found Dyoplosaurus to be a valid taxon (had triangular claws)
• In 2010 Victoria Arbour said Anodontosaurus was a valid taxon (different skull and certical ring ornamentation, and had pointed, triangular knob osteoderms)
• Paul Penkalski and William Blows said in 2013 Scolosaurus was a valid taxon
• Another study by Penkalski in 2013 named and described Oohkotokia based on fossils originally thought to be Euoplocephalus
• In 2013 Arbour said that Scolosaurus cutleri, Anodontosaurus lambei, Dyoplosaurus acutosquamens, and Euoplocephalus tutus were all valid, and Euoplocephalus lasted about 2 million years
• Victoria Arbour and Phil Currie found in 2013 that Euoplocephalus does not have round osteoderms at the based of the horns at the back of the head, it has sacral ribs that perpendicularly point outwards, had keeled osteoderms with a round or oval base
• Can see Euoplocephalus at the Hall of Fossils, at the Smithsonian National Museum of Natural History in Washington, D.C.

Fun Fact: It took about one million years for animal life in the Antarctic sea to recover after the Chicxulub impact.