In our 98th episode, we had the pleasure of speaking with Dr. Victoria Arbour, a NSERC Postdoctoral Fellow at the Royal Ontario Museum/University of Toronto, Canada and an ankylosaur expert. You can follow her on twitter @VictoriaArbour
Episode 98 is also about Homalocephale (Prenocephale), a pachycephalosaurid that lived in the late Cretaceous in what is now Mongolia.
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In this episode, we discuss:
- The dinosaur of the day: Homalocephale (Prenocephale)
- Homalocephale name means “even head”
- A pachycephalosaurid that lived in the late Cretaceous in what is now Mongolia
- Described in 1974 by Osmólska & Maryañska
- Only one species, type species is Homalocephale calathocercos
- May be a synonym (and juvenile form) of Prenocephale
- Type species is an incomplete skull and postcranial material. Had large openings on the top of the skull and a large, round eye socket. Scientists described it as an adult, even though it has juvenile traits (like a flat skull). Then in 2010 Nick Longrich and others said it may just be a juvenile version of another adult pachycephalosaur (Horner and Goodwin also suggested that in 2009). Longrich suggested it was a juvenile or sub-adult of Prenocephale
- Herbivore, about 6 ft (1.8 m) long
- Had a flat, wedge-shaped skull roof, though the skull was pretty thick (this is similar to Dracorex and Goyocephale, and not similar to other adult pachcephalosaurs)
- Had a broad pelvis (some paleontologists think it may have had wide hips to give live birth, others think the wide hips helped protect organs during flank-butting)
- Had long legs and was fast
- Had a very rigid tail
- Can see Homalocephale in the game Jurassic Park: Operation Genesis (you build your own Jurassic Park)
- Maryanska and Osmolska described Prenocephale in 1974
- Name means “sloped head”
- Lived in Mongolia in the late Cretaceous
- Fossils found include skulls and fragmentary post cranial remains
- Three species: Prenocephale prenes, Prenocephale brevis, Prenocephale edmontonensis
- Type species is Prenocephae prenes
- Another suggested synonym to Prenocephale is Sphaerotholus buchholtzae
- Herbivore, about 7.8 ft (2.4 m) long, weighing 280 lb (130 kg)
- Prenocephale had a round, sloping head, with a row of smally bony spikes and bumps
- Thought to have a stout body with a short neck, short forelimbs, and long legs (based on other pachycephalosaurs, since all that’s been found is mostly skulls
- Some scientists think Prenocephale may have been an omnivore (ate plants and insects), though many think it ate leaves and fruit
- Probably a selective browser, since it had a narrower snout than other pachycephalosaurs
- Pachycephalosaurs may have head butted or they may have used their domes to attract mates
- Teenage or young adult pachycephalosaurs were best equipped to handle head butting (skulls had radiating structures that compressed, provided cushion during a fight)
- Adults don’t have these structures
- Common Functional Correlates of Head-Strike Behavior in the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls published in PLOS ONE June 2011, by Eric Snively and Jessica M. Theodor
- Snively and Theodor compared Stegoceras and Prenocephale skulls with head-butting mammals (like elk and musk ox) with CT scans. They found Stegoceras and Prenocephale domes were most similar to musk ox and duiker
- Stegoceras was most able to head butt
- Distributions of Cranial Pathologies Provide Evidence for Head-Butting in Dome-Headed Dinosaurs (Pachycephalosauridae) published in PLOS ONE July 2013, by Joesph E. Peterson, Collin Dischler, Nicholas R. Longrich
- Peterson and his team studied 109 domes from 14 species to see if there was evidence of head butting. 22% of those domes showed evidence of osteomyelitis, which often comes from skull trauma. Because there was a lot of evidence of this, they concluded it was consistent with the idea of intraspecies combat
- They also looked at 30 skeletons of head-butting mammals and found that “Comparisons with injuries in extant bovids illustrate the variation in injury and lesion distribution related to behavior and suggest that the distribution of injuries in extinct animals can therefore be similarly used to infer behavior in extinct taxa”
- Pachycephalosauria is a clade of ornithischians
- Name means thick headed lizards
- Lived in the late Cretaceous in North America and Asia
- Bipedal with thick skulls
- Fun fact:
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 Dr. Victoria Arbour:
