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 www.ivpp-avianevolution.com
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On this episode, we focus on:
Information:
- The very best sauropod discover from Switzerland lastly has its personal genus—Amanzia supply
- Find out about dinosaurs whereas social distancing bit.ly/dinodistancing supply
- Convey Dinosaurs into your private home 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 based mostly 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 an enormous distinction in measurement, however might present particular person variation or sexual dimorphism
- Heterodontisauridae have among the smallest dinosaurs, like Fruitadens (about 26 to 30 in or 65 to 75 cm lengthy)
- Had a brief physique with a protracted tail
- In all probability bipedal
- In all probability a quick runner
- Had lengthy, strong forelimbs that have been about 70% so long as the hindlimbs
- Had sturdy arms, initially regarded as quadrupedal however now thought Heterodontosaurus used its arms for digging up roots and opening insect nests
- Arms considerably resembled early theropods, like Eoraptor and Herrerasaurus
- Had 5 fingers on every hand that have been lengthy
- Had massive palms, and it used the 5 fingers for greedy
- First three fingers had massive claws
- Fourth and fifth fingers have been probably vestigial
- Two of its fingers have been opposable, so it might choose 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 have been claw-like, not hoof-like (extra superior ornithischians have been extra hoof-like)
- No ossified tendons within the tail, so was most likely versatile
- Has been depicted as having lengthy, filamentous integuments from its neck to tail (seems to be bristly), based mostly on an outline of fellow heterodontosaurid Tianyulong, described in 2009, which had these constructions
- Had an S-shaped neck
- Had a small, elongated, slim, triangular cranium
- Had massive eye openings
- In all probability herbivorous, or possibly omnivorous
- Had a attractive beak that coated the entrance jaws
- Had three sorts of enamel: small, incisor-like enamel, lengthy canine-like tusks, and chisel-like/molar-like cheek enamel
- No enamel within the beak half
- Premaxilla (tip of the higher jaw) had three enamel on both sides. First two enamel have been small, and cone-shaped (incisors) and partially coated by the higher beak, and the third tooth on both sides was a canine-like tusk
- First two enamel within the decrease jaw have been canine-like tusks, and greater than those within the higher jaw
- Had 11 chisel-like cheek enamel on both sides, for crushing and grinding, after a niche after the canine-like enamel. Center cheek enamel have been the most important, they usually decreased in measurement. Had lengthy roots, and a heavy enamel coat (good for put on)
- Cheek enamel have uniform put on and tear, in order that they shaped on the identical time. No proof of newly erupted enamel
- In all probability moved its jaw forwards and backwards
- Thulborn prompt that Heterodontosaurus wanted to interchange its enamel repeatedly, as a result of it ate robust vegetation. It could have finished that with aestivation (like hiberation however in summer time), when it wouldn’t must eat. Could have labored, because it lived in a desert-like habitat with sizzling, dry seasons with little meals
- Hopson questioned this in 1980 and located put on patterns on the enamel that confirmed vertical and lateral, not forwards and backwards actions. Additionally discovered variables in tooth put on, which confirmed steady enamel alternative, although he did say X-rays of essentially the most full specimen didn’t present any unerupted alternative enamel
- Hopson rejected the aestivation thought on account of lack of proof
- Butler and others in 2006 CT scanned a juvenile Heterodontosaurus cranium and located no alternative enamel. However they argued there should have been tooth alternative as a result of the juvenile had the identical tooth morphology as adults, and the enamel 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 enamel. Sereno in 2012 described a juvenile with unerupted alternative enamel
- However in 2012, Sereno mentioned Heterodontosaurus had some options in its cranium and enamel that confirmed an herbivorous weight loss program (the beak with the cheek enamel for slicing vegetation, and the cheeks to maintain meals in its mouth whereas chewing, the enlarged jaw muscle tissue, and place of the jaw joint so the chunk could be evenly unfold. In all probability ate robust vegetation
- Hear extra about chewing and jaw muscle tissue of herbivorous dinosaurs, try our interview with Ali
- https://iknowdino.com/Yamaceratops-episode-205/
- Since Heterodontosaurus was so basal, it could assist present the shift from early carnivorous dinosaurs to being herbivorous
- Laura Porro in 2008 mentioned “It’s possible that every one dinosaurs developed from carnivorous ancestors. Since Heterodontosaurs are among the many earliest dinosaurs tailored to consuming crops, they could symbolize a transition section between meat-eating ancestors and extra refined, fully-herbivorous descendants.”
- Not many juveniles have been discovered, so not a lot identified 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 enamel
- Kinds of enamel have been the identical, so juveniles and adults most likely had comparable diets
- Thulborn in 1974 thought that there was sexual dimorphism with tusks (males had tusks, females didn’t), however tusks have 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 have 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 sometimes (to go together with the claws). Going after prey could be a bonus within the dry season when there was much less vegetation
- A 2016 examine discovered that Heterodontosaurus might have used its tusks by grazing towards the decrease beak whereas it was cropping vegetation
- Heterodontosauridae is without doubt one of the most primitive/basal teams of ornithischian dinosaurs
- Heterodontosaurids largely present in southern Africa, however have additionally been present in Eurasia and the Americas
- Kind and solely species: Heterodontosaurus tucki
- Genus title means “totally different toothed lizard” and refers to its enamel, which have been uncommon (and all totally 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 based mostly on a cranium, by Alfred Crompton and Alan Charig (cranium was practically full and barely crushed)
- Holotype cranium was crushed however practically 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 mentioned the outline was preliminary
- Only a few early ornithischians have been identified on the time
- Laborious to organize the specimen, as a result of it was coated in a skinny, onerous, rusty layer containing haematite that might 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 degree, 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 straight associated)
- Different specimens have been discovered, together with one in 2005 in a streambed close to Grahamstown in Jap Cape Province of South Africa, which is essentially the most full particular person discovered thus far, however was too onerous 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 prompt 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 mentioned it was a definite species due to small variations within the enamel 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 have been in the identical household, however thought they have been nonetheless separate genera, particularly for the reason that holotype of Lycorhinus angustidens (the sort specimen) was so fragmentary and never effectively preserved so it was onerous to match towards. James Hopson finally appeared on the holotype of Lycorhinus and mentioned 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 reminiscent of Lycorhinus, Abrictosaurus, and Pegomastax. Different animals included amphibians, turtles, and crocodylomorphs
Enjoyable Truth:
Fashionable dinosaurs (birds) have the next physique temperature than people.
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