Episode 434: Therizinosaurus had weak claws. Did Therizinosaurus have claws that were too large to be useful? Did Alvarezsaurus have claws that were too small? How dinosaurs played, how raptors used their claws, and dinosaurs in space.

News:

• Alvarezsaurs and therizinosaurs were weird, and the giant claws of Therizinosaurus were surprisingly weak source
• Scientists studied birds to figure out how dinosaurs may have played source
• Raptors probably used their “killing claws” to pin their prey, rather than slash at prey. source

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The dinosaur of the day: Struthiosaurus

• Nodosaurid dinosaur that lived in the Late Cretaceous in what is now Austria, Romania, France, Spain, and Hungary
• Not to be confused with the ornithomimid Struthiomimus (which was more bird-like)
• May be one of the most basal ankylosaurs
• Looked somewhat like other nodosaurids, like Borealopelta
• Walked on four legs, had large shoulder spikes, had an elongate head, body covered in armor, but no tail club
• As Garret put it when we talked about Struthiosaurus’ hearing in episode 274, it was “like a big tanky dog covered in armor and spikes”
• May have been a dwarf dinosaur
• Estimated to be about 6.6 to 9.8 ft (2 to 3 m) long and weighed about 660 lb (330 kg)
• At the time Struthiosaurus lived, what is now Europe was mostly islands
• In 2017 Norbert Frotzler, in a pre-print paper, reconstructed Struthiosaurus austriacus
• Part of the 650th anniversary celebrations of the University of Vienna (in 2015)
• Frotzler was asked to prepare a diagram of Struthiosaurus and presented the reconstruction at the anniversary celebration
• Paper was an explanation of that reconstruction
• Described Struthiosaurus as “conspicuously small” with a long neck, and “probably, it was feeding mainly on ants and termites, at least when a juvenile animal”
• Type species is Struthiosaurus austriacus
• Eduard Suess, a geologist, found a dinosaur tooth in 1859 at a coal mine in Austria (on top of a stone pile)
• Tried to find more fossils, and eventually they found a thin marl layer with a lot of bones (fresh water deposit, part of the Grünbach Formation)
• Fossils stored at the museum of the University of Vienna, and not studied until 1870
• Emanuel Bunzel studied the fossils and named a few new dinosaurs, including Struthiosaurus, based on part of the skull and braincase
• Named in 1871
• Genus name means “ostrich lizard”
• Genus name refers to the birdlike-ness of the braincase
• Species name refers to the provenance from Austria where the fossils were found
• Bunzel also described other Struthiosaurus fossils and osteoderms, but he referred them to Scelidosaurus and Hylaeosaurus
• He also described rib fragments that he thought were from a giant lizard, because they had double-headed ribs (which means more joints between the ribs and vertebrae and therefore the rib cage could be more mobile), which he named Danubiosaurus anceps (after the Danube River—the name is a nod to Mosasaurus which was named after the River Maas)
• All those bones turned out to be from Struthiosaurus
• Bunzel knew the braincase was from a reptile but the braincase was different from lizards and crocodiles (was low, compact, and had a gradual curve to the skull roof)
• Thought the braincase could be from a dinosaur, but wasn’t sure, and thought it might be a bird based on how the bones rounded and fused
• Sent a drawing and description to Thomas Huxley, who agreed it was like a bird
• Bunzel wrote in his description of the fossils “with time, it might also be possible to create an order Ornithocephala (“bird heads”)”
• Hard to know it was an ankylosaur braincase at the time because it was the first one described, and there were only fragments so the skull seemed to be lightly built
• Bunzel didn’t really have osteoderms when he described the fossils
• Nopcsa in 1902 found it was an ankylosaur, and in 1978 Walter Coombs said it was a nodosaurid
• At least three individuals of different ages of Struthiosaurus austriacus were found in Austria, according to Suberbiola and Galton in 2001
• Used to be many species of Struthiosaurus, based on fragmentary fossils and material that did not have unique features (nondiagnostic)
• Animals that have been found to actually be Struthiosaurus include rataeomus,? ?Danubiosaurus,? ?Leipsanosaurus,? ?Pleuropeltus,? ?Rhodanosaurus,? ?Hoplosaurus
• In 1881, Seeley examined Bunzel’s fossils and found many of the bones, plates, and teeth were part of one dinosaur, which he named Crataeomus (which means “mighty shoulder”). Nopcsa later synonymized Crataeomus with Struthiosaurus
• Turned out to be part of Struthiosaurus
• Three valid species today: Struthiosaurus austriacus, Struthiosaurus transylvanicus (named by Nopcsa in 1915), and Struthiosaurus languedocensis (named by Garcia and Pereda-Suberbiola in 2003)
• In 2003 Géraldine Garcia and Xabier Pereda Suberbiola described Struthiosaurus languedocensis, based on a partial skeleton of an adult found in southern France in 1998
• Species name refers to Languedoc, the region where the fossils were found
• Struthiosaurus austriacus was smaller than Struthiosaurus transylvanicus and had shorter neck vertebrae
• Struthiosaurus languedocensis had flatter dorsal vertebrae and a different shaped ischium (pelvis)
• Briefly mentioned in episode 400, with the other Hateg dinosaurs
• However, “‘Struthiosaurus” transylvanicus is often referred to in quotes
• Fossils Nopcsa described include parts of the skull, vertebrae, part of the shoulder, and armor
• Coombs and Maryanska considered Struthiosaurus austriacus to be a nomen dubium
• In 1997, Suberbiola and Galton said the “Struthiosaurus” transylvanicus may be valid but the fossils are probably inadequate to show its different from Struthiosaurus austriacus
• In 2013, Attila Osi and Edina Prondvai tentatively assigned a humerus (arm bone), of an adult dinosaur (based on histology), found in Hungary to Struthiosaurus
• Helps show that two nodosaurids lived alongside each other in the area, which means there was more diversity in European ankylosaurs than previously thought
• The other nodosaurid, Hungarosaurus, was almost twice the size of Struthiosaurus
• Talked about Struthiosaurus in episode 374
• Paper published in 2022 by Marco Schade and others
• Re-examined the holotype braincase using micro-CT scanning
• Had relatively short semicircular canals (inner ear)
• Large semicircular canals make animals better at balancing and more sensitive to head movements
• Struthiosaurus also didn’t have a floccular recess, which helps stabilize vision when moving your head and is linked to motor control
• And had the shortest cochlear duct of any known dinosaur, which probably means it couldn’t hear very well (maybe a little better than a turtle)
• Authors also found lots of blood vessels around the brain which helps show it may have used extra blood vessels to cool down their brains
• Taken altogether, means it probably spent a lot of its time alone, eating, and wasn’t very active
• Also talked about Struthiosaurus in episode 377 when Garret pondered if it could rely on infrasound to hear
• Struthiosaurus could hear down to about 300Hz (around Middle C on a piano)
• Under 20Hz is considered infrasound, so Struthiosaurus couldn’t use it (elephants and blue whales can though)

Fun Fact:

Dinosaurs never saw Halley’s comet.

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