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I Know Dino Podcast: Stegoceras

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    Episode 41 is all about Stegoceras, a pachycephalosaurid with a clean domed head.

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    On this episode, we focus on:

    • The dinosaur of the day: Stegoceras, whose identify means “horned roof”
    • Pachycephalosaurid dinosaur that lived in North America in the course of the Late Cretaceous
    • First named in 1902, by Lawrence Lambe

    • Bones first present in 1889
    • When Stegoceras was first discovered, scientists thought the bones had been stomach ribs, which aren’t present in different ornithischians (however now considered ossified tendons
    • Kind species is Stegoceras validum (based mostly on 40 specimens discovered within the Stomach River Group of Alberta, Canada)

    • Between the Nineteen Twenties to 1945, Stegoceras was considered Troodon, as a result of they’d comparable enamel (however then higher specimens had been discovered)
    • Was extra Stegoceras species, comparable to Stegoceras lambei, Stegoceras sternbergi, and Stegoceras breve, however had been later assigned to different genera
    • In 1983 Stegoceras browni was renamed Ornatotholus, however is now thought of to be a juvenile of S. validum

    • One genus, Ornatotholus, is considered a juvenile Stegoceras validum, based mostly on an evaluation of the cranial dome ontogeny
    • 2011 PLOS ONE Cranial Ontogeny in Stegoceras validum (Dinosauria: Pachycephalosauria): A Quantitative Mannequin of Pachycephalosaur Dome Progress and Variation”: research that exhibits the cranium modified with age and Ornatotholus browni is a juvenile of S. validium
    • In 1990, Mark Goodwin described the cranium of an grownup Stegoceras, however the cranium was massive for a Stegoceras. In 2003, Robert Sullivan wrote a evaluation of the fossils discovered, and thought it was distinct sufficient to be named Hanssuesia sternbergi. However a more moderen research by Ryan Schott and David Evans argues the cranium is an grownup Stegoceras, though it lacked nodes at the back of the cranium which is seen on youthful Stegoceras (unsure why it doesn’t have the nodes, attainable they only modified with age)

    • In 2011, a brand new legitimate species was named by Steven E. Jasinski and Robert M. Sullivan, known as Stegoceras novomexicanum, based mostly on two partial skulls
    • Stegoceras novomexicanum was solely about 4 ft lengthy, in comparison with S. valdium which was over 6 ft lengthy
    • Stegoceras is a extra widespread, higher recognized pachycephalosaur

    • A part of the group Marginocephalia and Pachycephalosauria
    • In all probability developed from Hypsilophodon (from episode 28)
    • Bones have been present in Alberta Canada and New Mexico

    • About 6.6 ft (2 m) lengthy and weighed 22-88 lb (10-40 kg)
    • About 4 ft or 1.2 m tall
    • Bipedal

    • Could have gone on all 4 ft to search for crops to eat
    • Had small enamel that had been curved, with serrated edges (once more, much like Troodon)
    • Had legs thrice longer than arms

    • Had an S- or U-shaped neck
    • Stegoceras had spherical ahead going through eye sockets, so most likely had good imaginative and prescient and binocular imaginative and prescient
    • In all probability a herding dinosaur

    • Different dinosaurs that lived by Stegoceras had been Albertosaurus, Maiasaura, T-rex, Ankylosaurus, Parasaurolophus, Corythosaurus and Dryptosaurus
    • Had a big mind that was in a thick dome about 3 in or 7.5 cm thick (and divided into two components)
    • The dome was clean

    • Males had thicker domes than females (so did older Stegoceras)
    • In 1981 the Journal of Paleontology revealed “A Morphometric Examine of the Carnium of the Pachycephalosaurid Dinosaur Stegoceras” which measured the braincases of 29 specimens and located that what was as soon as considered two kinds of Stegoceras was simply female and male (males had thicker domes than females)
    • Scientists initially thought male Stegoceras rammed their heads collectively (like bighorn sheep or musk oxen), however in 1997 some paleontologists stated the dome was not massive sufficient for that form of influence, and wouldn’t have labored until the heads hit at simply the proper spot; additionally, their head, neck and physique would have needed to be in a horizontal line to transmit stress, however scientists assume their necks had been S- or U-shaped; an alternate is flank-butting, which includes shifting the neck and rotating the pinnacle and never severely injure the opponent (bone rim above the attention could have protected its eyes)

    • Mark Goodwin from College of California Berkeley analyzed pachycephalosaur skulls and located no proof of healed scars, and located hat the cranium bone is porous and fragile beneath strain, so they might have killed one another in fights
    • In 2011 Eric Snively and Theodor analyzed CT scans of Stegoceras validum skulls, and located they may have head-butted, based mostly on an additional layer of dense bone in the midst of the dome, which might have been additional safety
    • Eric Snively and researched revealed a research in 2011 in PLOS One  known as”Frequent Useful Correlates of Head-Strike Habits within the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls” that confirmed Stegoceras may have head butted

    • They did CT scans on fashionable animal skulls and Stegoceras, then made a digital simulation exhibiting beasts going face to face
    • Discovered its mind was extra protected than bighorn sheep and musk ox
    • Stegoceras had an additional layer of dense bone in the midst of its dome, along with a stiff rind exterior with spongy materials that may take up vitality (and hold them aware when butting heads)

    • Eric Snively stated there are “alternating layers of stiff and compliant bone within the domes…nearly as if they’re carrying a double motorbike helmet”
    • Could have butted heads to draw mates
    • The research of Stegoceras that discovered the domes may dissipate influence forces doesn’t show they rammed heads, they might have flanked one another by swinging their heads into every others sides as a substitute

    • Stegoceras was a heavy breather
    • In 2014 Anatomical Document revealed Jason Bourke and his staff’s research that confirmed Stegoceras cooled its mind by respiration
    • It breathed like a chicken or reptile and took lengthy, deep breaths, based mostly on a CT scan by Jason Bourke and colleagues (respiration helped cool its mind by cooling blood vessels within the mind; additionally could haven’t had nostril hairs like fashionable reptiles so would have had numerous mucous to keep away from inhaling small, airborne objects

    • Dinosaurs didn’t have nostril hairs (wanted mucous)
    • Bourke and colleagues scanned the Stegoceras cranium and located the turbinates
    • Jason Bourke from the College of Ohio discovered that Stegoceras had turbinates, intricate constructions of their nostril, to assist cool blood and forestall water loss

    • They ran digital air by way of a 3D mannequin of the dinosaur’s nostril to see how the turbinates altered airflow
    • That’s how they discovered it acted as a cooling system, the place the air breathed in cooled the nice and cozy blood inside earlier than flowing to the mind (helped them hold cool when working away from predators)
    • As a result of dinosaurs had been so massive, overheating was a serious subject

    • Stegoceras is a comparatively small dinosaur, however nonetheless cooled its mind
    • Had a great sense of scent, to smell out predators, mates, and meals
    • Marginocephalia (“fringed heads”) is a clade of ornithiscians that had been herbivores (each bipedal and quadrupedal), with bony ridges of frills in the back of the cranium; lived in Jurassic and Cretaceous

    • Pachycephalosauria (“thick headed lizards”) can be a clade of ornithiscians; lived within the late Cretaceous in North America and Asia
    • Pachycephalosaurs had been herbivores with thick skulls
    • They had been all bipedal

    • Had thick skulls
    • Some had domed skulls, others flat or wedge formed
    • Enjoyable Reality: The phaeomelanosomes that probably saved pigments in dinosaurs’ crimson feathers is identical because the pigment that makes Garret’s hair crimson!



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