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Episode 279: Traces of DNA in dinosaur cartilage


    Episode 279 is all about Heterodontosaurus, a dinosaur with tusks and a beak.

    We additionally interview Alida Bailleul, Postdoctoral Analysis Fellow on the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP). Her analysis focuses on microscopic construction of dinosaur bone and tissue. Observe her work at

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    On this episode, we focus on:


    • The very best sauropod discover from Switzerland lastly has its personal genus—Amanzia supply
    • Study dinosaurs whereas social distancing supply
    • Deliver Dinosaurs into your house with a brand new AR App supply

    The dinosaur of the day: Heterodontosaurus

    • Heterodontosaurid ornithischian that lived within the Early Jurassic in what’s now South Africa
    • Small dinosaur, between about 3 ft 10 in (1.18 m) to five ft 9 in (1.75 m) lengthy and weighed between 4.4 to 22 lb (2 to 10 kg)
    • Estimates primarily based on the holotype and a second specimen
    • Second specimen was a lot bigger than the holotype (22 lb / 10 kg and as much as 5 ft 9 in or 1.75 m lengthy, in comparison with about 4 lb pr 1.8 kg and three ft 10 in or 1.18 m lengthy). Not clear why there was such a giant distinction in measurement, however might present particular person variation or sexual dimorphism
    • Heterodontisauridae have a few of the smallest dinosaurs, like Fruitadens (about 26 to 30 in or 65 to 75 cm lengthy)
    • Had a brief physique with a protracted tail
    • Most likely bipedal
    • Most likely a quick runner
    • Had lengthy, sturdy forelimbs that had been about 70% so long as the hindlimbs
    • Had robust arms, initially regarded as quadrupedal however now thought Heterodontosaurus used its arms for digging up roots and opening insect nests
    • Palms considerably resembled early theropods, like Eoraptor and Herrerasaurus
    • Had 5 fingers on every hand that had been lengthy
    • Had massive palms, and it used the 5 fingers for greedy
    • First three fingers had massive claws
    • Fourth and fifth fingers had been probably vestigial
    • Two of its fingers had been opposable, so it might decide issues up with one hand
    • Had lengthy, slender hind limbs, and 4 toes on every foot
    • The primary toe on the foot (hallux) didn’t contact the bottom
    • Bones within the toes had been claw-like, not hoof-like (extra superior ornithischians had been extra hoof-like)
    • No ossified tendons within the tail, so was in all probability versatile
    • Has been depicted as having lengthy, filamentous integuments from its neck to tail (appears bristly), primarily based on an outline of fellow heterodontosaurid Tianyulong, described in 2009, which had these constructions
    • Had an S-shaped neck
    • Had a small, elongated, slender, triangular cranium
    • Had massive eye openings
    • Most likely herbivorous, or possibly omnivorous
    • Had a sexy beak that lined the entrance jaws
    • Had three sorts of tooth: small, incisor-like tooth, lengthy canine-like tusks, and chisel-like/molar-like cheek tooth
    • No tooth within the beak half
    • Premaxilla (tip of the higher jaw) had three tooth on either side. First two tooth had been small, and cone-shaped (incisors) and partially lined by the higher beak, and the third tooth on either side was a canine-like tusk
    • First two tooth within the decrease jaw had been canine-like tusks, and greater than those within the higher jaw
    • Had 11 chisel-like cheek tooth on either side, for crushing and grinding, after a niche after the canine-like tooth. Center cheek tooth had been the most important, they usually decreased in measurement. Had lengthy roots, and a heavy enamel coat (good for put on)
    • Cheek tooth have uniform put on and tear, in order that they fashioned on the similar time. No proof of newly erupted tooth
    • Most likely moved its jaw forwards and backwards
    • Thulborn steered that Heterodontosaurus wanted to interchange its tooth often, as a result of it ate powerful vegetation. It could have achieved that with aestivation (like hiberation however in summer season), when it wouldn’t have to eat. Could have labored, because it lived in a desert-like habitat with scorching, dry seasons with little meals
    • Hopson questioned this in 1980 and located put on patterns on the tooth that confirmed vertical and lateral, not forwards and backwards actions. Additionally discovered variables in tooth put on, which confirmed steady tooth alternative, although he did say X-rays of probably the most full specimen didn’t present any unerupted alternative tooth
    • Hopson rejected the aestivation thought as a result of lack of proof
    • Butler and others in 2006 CT scanned a juvenile Heterodontosaurus cranium and located no alternative tooth. However they argued there should have been tooth alternative as a result of the juvenile had the identical tooth morphology as adults, and the tooth would have modified if the tooth grew constantly. They concluded Heterodontosaurus had sporadic tooth alternative
    • In 2011, Norman and others described the higher jaw of one other specimen, and located unerupted alternative tooth. Sereno in 2012 described a juvenile with unerupted alternative tooth
    • However in 2012, Sereno stated Heterodontosaurus had some options in its cranium and tooth that confirmed an herbivorous weight loss plan (the beak with the cheek tooth for chopping vegetation, and the cheeks to maintain meals in its mouth whereas chewing, the enlarged jaw muscle groups, and place of the jaw joint so the chunk can be evenly unfold. Most likely ate powerful vegetation
    • Hear extra about chewing and jaw muscle groups of herbivorous dinosaurs, take a look at our interview with Ali
    • Since Heterodontosaurus was so basal, it could assist present the shift from early carnivorous dinosaurs to being herbivorous
    • Laura Porro in 2008 stated “It’s possible that each one dinosaurs advanced from carnivorous ancestors. Since Heterodontosaurs are among the many earliest dinosaurs tailored to consuming crops, they could signify a transition section between meat-eating ancestors and extra refined, fully-herbivorous descendants.”
    • Not many juveniles have been discovered, so not a lot recognized about the way it modified because it grew, however eye sockets appear to have shrunk because it grew up, and the snout turned longer and had extra tooth
    • Varieties of tooth had been the identical, so juveniles and adults in all probability had related diets
    • Thulborn in 1974 thought that there was sexual dimorphism with tusks (males had tusks, females didn’t), however tusks had been present in a juvenile cranium, so wouldn’t be one thing that develops later for mating. Additionally, most skulls discovered have tusks
    • Initially tusks had been thought for use for protection or show, and that Heterodontosaurus was herbivorous. However now, thought that Heterodontosaurus might have been omnivorous and used tusks for killing prey often (to go along with the claws). Going after prey can be a bonus within the dry season when there was much less vegetation
    • A 2016 research discovered that Heterodontosaurus might have used its tusks by grazing in opposition to the decrease beak whereas it was cropping vegetation
    • Heterodontosauridae is among the most primitive/basal teams of ornithischian dinosaurs
    • Heterodontosaurids principally present in southern Africa, however have additionally been present in Eurasia and the Americas
    • Sort and solely species: Heterodontosaurus tucki
    • Genus title means “completely different toothed lizard” and refers to its tooth, which had been uncommon (and all completely different, or heterodont)
    • Species title in honor of George C. Tuck, managing director of the Austin Motor Firm of South Africa, who supported the expedition
    • Holotype discovered throughout a British and South African expedition between 1961-1962, on a mountain at an altitude of about 6,200 ft (1,890 m)
    • Described and named in 1962 primarily based on a cranium, by Alfred Crompton and Alan Charig (cranium was almost full and barely crushed)
    • Holotype cranium was crushed however almost full (postcranial stays that belonged to the cranium not discovered till 2011)
    • Holotype is now on the Iziko South African Museum
    • Solely described the entrance a part of the cranium and decrease jaw after they named Heterodontosaurus, and stated the outline was preliminary
    • Only a few early ornithischians had been recognized on the time
    • Onerous to arrange the specimen, as a result of it was lined in a skinny, arduous, rusty layer containing haematite that would solely be eliminated utilizing a diamond noticed, which broken the specimen
    • Second specimen present in 1966 within the Eliot Formation, about 5,807 ft (1,770) m above sea stage, on Krommespruit Mountain. Included the cranium and skeleton, articulated
    • Second specimen described in 1976 by Albert Santa Luca, Crompton, and Charig
    • Forelimbs had been mentioned in an article by Peter Galton and Bob Bakker in 1974, and helped set up that Dinosauria was a monophyletic pure group (many scientists on the time thought Saurichia and Ornithischia weren’t immediately associated)
    • Different specimens have been discovered, together with one in 2005 in a streambed close to Grahamstown in Japanese Cape Province of South Africa, which is probably the most full particular person discovered up to now, however was too arduous to take away due to the rocks round it. So it was scanned on the European Synchrotron Radiation Facility in 2016. They took 5 days to scan, and located it was a juvenile
    • Richard Thulborn steered Heterodontosaurus was a junior synonym to Lycorhinus in 1970. Lycorhinus was named in 1924, and was additionally present in South Africa. He reclassified Heterodontosaurus tucki to Lycorhinus tucki, and stated it was a definite species due to small variations within the tooth and the place it was discovered
    • Thulborn additionally named a 3rd species of Lycorhinus, Lycorhinus consors. Although Galton in 1973 disagreed with the synonymization. Charig and Crompton agreed in 1974 that Heterodontosaurus and Lycorhinus had been in the identical household, however thought they had been nonetheless separate genera, particularly because the holotype of Lycorhinus angustidens (the kind specimen) was so fragmentary and never effectively preserved so it was arduous to check in opposition to. James Hopson ultimately appeared on the holotype of Lycorhinus and stated Heterodontosaurus was its personal genera in 1975. He additionally modified Lycorhinus consors to be Abrictosaurus consors
    • Different dinosaurs that lived in the identical time and place included Lesothosaurus, Massospondylus, and the theropod Meapnosaurus, in addition to different heterodontosaurids akin to Lycorhinus, Abrictosaurus, and Pegomastax. Different animals included amphibians, turtles, and crocodylomorphs

    Enjoyable Reality:
    Fashionable dinosaurs (birds) have the next physique temperature than people.


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