Episode 40 is all about Massospondylus, a sauropodomorph with thumb claws and forelimbs half the size of its hindlimbs.
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On this episode, we focus on:
- The dinosaur of the day: Massospondylus
- Lived within the early Jurassic
- Sort species is Massospondylus carinatus (7 species named in 150 years, however 2 species are nonetheless legitimate)
- Fossils have been present in South Africa, Lesotho and Zimbabwe (different fossils initially regarded as Massospondylus however are actually different species have been present in Arizona, India and Argentina
- Richard Owen described it in 1854, based mostly on fossils present in South Africa (one of many first dinosaurs named)
- Initially Owen didn’t assume the Massospondylus bones have been dinosaur bones; he thought they have been “giant, extinct, carnivorous reptiles” associated to lizards, chameleons and iguanas
- Joseph Millard Orpen discovered 56 bones (together with vertebrae from neck, again and tail, shoulder blade, humerus, partial pelvis, femur, tibia, and bones from arms and toes) in 1853 in South Africa and donated them to the Hunterian Museum on the Royal Faculty of Surgeons in London. Bones have been disarticulated, so it was exhausting to inform if all of them got here from the identical species
- All these fossils have been destroyed on Could 10, 1941, when a German bomb hit the Hunterian Museum
- 80 partial skeletons and 4 skulls have been present in South Africa, Lesotho and Zimbabwe
- A cranium in AZ was present in 1985, regarded as Massospondylus. It was 25% bigger than different skulls discovered, however a latest examine recognized it as a brand new genus, Sarahsaurus
- Fossils additionally present in Argentina, however was named Adeopapposaurus in 2009
- Former species embrace M. browni (1895), M. harriesi (1911), M. hislopi (1890), M. hueni (1981), M. rawsei (1890) and M. schwarzi (1924)
- M. browni, M. harriesi and M. schwarzi present in South Africa, fragmentary materials (considered indeterminate)
- M. hislopi and M. rawsei present in India, and M. hislopi is indeterminate however M. rawesi could also be a theropod
- M. hueni was a mix of Lufengosaurus and Massospondylus (regarded as synonyms, however that is not accepted)
- M. kaalae (named 2009) based mostly on a partial cranium from South Africa, from identical time and space as M. carinatus (however barely completely different braincase)
- Different doubtful, synonymous, or junior synonyms of Massospondylus embrace Leptospondylus, Pachyspondylus, Aristosaurus, Dromicosaurus, Gryponyx taylori, Hortalotarsus (named in 1894 however based on Broom in 1911, “Initially a lot of the skeleton was within the rock, and it was regarded by the farmers because the skeleton of a Bushman, however it’s stated to have been destroyed by worry {that a} Bushman skeleton within the rock may are inclined to weaken the non secular perception of the rising era.”
- One other synonym is Ignavusaurus
- Massospondylus was 13-20 toes (4-6 m) lengthy, lengthy neck and tail, small head, slender physique, with sharp, lengthy thumb claws (to assist eat or utilized in protection), and tiny fourth and fifth digits so the forepaws appears to be like lopsided
- Weighed round 2200 lb (1000 kg)
- 3 toes (1 m) tall and 13 toes (4 m) lengthy
- Just like Plateosaurus
- A 2005 examine discovered that Plateosaurus (comparable) had progress patterns based mostly on environmental elements (when in favorable local weather or round a lot of meals, grew quick; generally known as “developmental plasticity”), however this isn’t seen in different dinosaurs, together with Massospondylus
- One examine discovered Massospondylus grew steadily, one other discovered it grew most 76 lb or 34.6 kg per 12 months and grew till about age 15
- Forelimbs have been half the size of hindlimbs, however nonetheless highly effective
- Initially regarded as quadrupedal, however a 2007 examine discovered it was bipedal
- A 2007 examine discovered Massospondylus could have used brief arms to swat at predators in protection, fight with one another, or assist with feeding (arms have been too brief to achieve mouth although)
- Had a restricted vary of movement, based on a 2007 examine, so couldn’t have been quadrupedal (hand couldn’t rotate to face downwards, and forelimbs couldn’t swing in a method much like hindlimbs)
- Thumb claw used for digging, grooming, stripping vegetation, combating
- 2007 papers help Massospondylus as a household, Massospondylidae (although data of early sauropodomorphs retains altering)
- Massospondylus was a sauropodomorph (quadrupedal herbivore) and plateosaurid (heavy thick limbed herbivores)
- Sauropodomorphs that hyperlinks later sauropods to bipedal saurischians
- Massospondylus was most likely an herbivore, although early sauropodomorphs could have been omnivores
- Till the Nineteen Eighties, paleontologists sauropodomorphs like Massospondylus could have been carnivorous, however now they assume it may solely have been herbivorous or omnivorous, resulting from jaw articulation (based on a examine in 2004 by Galton and Upchurch)
- In 2000 one paleontologist stated they might have eaten small prey or carrion, and gastroliths have been discovered with three Massospondylus fossils in Zimbabwe
- Scientists thought gastroliths helped support in digestion, since they couldn’t chew, however Wings and Sander in 2007 confirmed that the big quantity of polished stones “precluded a use as an impact gastric mill in most non-theropod dinosaurs”
- 2007 Wings and Sander stated sauropods didn’t use gastroliths, and scientists discovered the theropod Louinhanosaurus used gastroliths
- Had two forms of tooth, small pointed tooth like theropods within the entrance of the mouth and spatulate tooth within the rear of the mouth (which is why debate over weight-reduction plan)
- Presumably had cheeks, probably had an overbite (some scientists thought it had a beak, however this appears unlikely)
- Variety of tooth varies relying on cranium measurement; largest one has 26 tooth on both sides of decrease jaw
- Predators not clear, most theropods from the identical time and place, reminiscent of Megapnosaurus, have been smaller than Massosponylus (could have slashed shortly to put on down prey, however Massospondylus would have used its foot claws
- One other potential predator was the theropod Dracovenator (20 ft) 6 m lengthy
- In 1976, 6-7 Massospondylus eggs (6 in or 15 cm lengthy) was present in South Africa by James Kitching, however took 30 years to begin the extraction. They’re the oldest dinosaur embryos discovered but
- Took 5 years to excavate the eggs present in 1976
- Kitching determined he didn’t have the assets to take away the fossil from the egg rock with out hurting the bones, so he targeted on the eggshells (till CT scanning) and located they have been much like crocodiles and birds
- In 1979, Kitching wrote a preliminary report, and located a cranium properly preserved, 10 mm from ear to ear
- As a result of the embryos couldn’t be properly studied, individuals debated whether or not they have been Massospondylus and even dinosaurs. A 2002 examine discovered they have been extra crocodilian than dinosaurian
- 2004, Reisz and Scott from the College of Toronto studied the eggs with CAT scans, however scans have been inconclusive as a result of it was too exhausting to tell apart rock from bone. Scott spent a 12 months getting ready the eggs, utilizing tiny air-driven jackhammers and skinny needles to take away the rock and searching on the eggs beneath a excessive powered microscope (discovered two dinosaur embryos within the fetal place)
- Onerous to investigate the eggs (femur is only one.4 mm in diameter)
- This confirmed the eggs have been Massospondylus
- Findings printed in 2005 of two practically full embryonic skeletons
- These eggs have been flown to Grenoble to be examined with a CT scan on the European Synchrotron Radiation Facility
- Till CT scanning, however the x-ray decision wanted is excessive (six microns) so only some locations on the planet may do it
- Will take some time to course of all the knowledge (1 TB) on the College of Witwatersrand’s Digital Paleontology Lab in Johannesburg
- Further findings printed in 2012, discovered 10 extra egg clutches, with as much as 34 eggs in every
- By early 2012, 10 egg clutches from 4 fossil horizons have been discovered, with as much as 34 eggs per clutch, so the nesting web site could have been used a number of instances; nesting space was close to a lake and eggshells have been skinny (0.1 mm), in order that they have been most likely partially buried within the substrate; no hints that Massospondylus made the nests, however the eggs have been organized in tight rows (most likely pushed there)
- Eggs have been most likely close to able to hatch; had giant heads with brief snouts and enormous eyes, brief neck; forelimbs and hindlimbs have been identical size (quadrupedal as infants, bipedal as adults); no tooth and couldn’t transfer a lot, so needed to be fed by mother and father till they doubled in measurement
- Hatchlings doubled in measurement earlier than leaving the nest (based mostly on footprint sizes)
- Moms have been too giant to incubate the eggs, in order that they clustered them
- Nests would not have any bowl-shaped depressions or indicators of nest development
- Communal nesting web site (energy in numbers to defend)
- Lake close to the nest typically flooded (seasonal cycle), and unhealthy timing could have resulted within the eggs paleontologists discovered
- Oldest identified dinosaur group nesting web site (others identified are 100 million years youthful)
- Habits reveals advanced reproductive conduct
- Sauropodomorphs (consists of prosauropods, which suggests earlier than the sauropods) have been giant, semi-quadrapeal, herbivores from the Triassic and early Jurassic
- Sauropodomorpha means “lizard toes types” and is a suborder or unranked (established by Friedrich von Huene in 1932), broke it into two teams Prosauropoda and Sauropoda
- No gaps between prosauropod and sauropod lineages, and up to date cladistic analyses recommend the clade Prosauropoda is a junior synonym of Plateosauridae
- Because of the truth that there’s no proof it’s simpler to cut back digits throughout evolution (prosauropods had a smaller outer toe on hindfeet in comparison with sauropods)
- 4 households: Platesauridae, Anchisauridae, Massospindylidae, and Melanorosauridae
- Discovered on most continents, and a few of the world’s oldest identified dinosaur bones
- Most lived in Europe, most likely (additionally present in Asia and Americas), and a few present in Madagascar
- Most likely herbivores, with uscular legs to face on two toes and eat tall vegetation
- Most likely traveled in teams
- They have been each quadrupedal and bipedal
- Forelimbs about half the size of hindlimbs
- Mouths have been like nutcrackers, however most likely couldn’t chew. As an alternative had gastric mills in abdomen partitions (stones embedded that grind meals), however they have been inefficient, in order that’s why they most likely went extinct
- Had tiny skulls
- Thumb claws for protection
- Had giant nostrils
- Presumably cathemeral
- Enjoyable Reality: Elevated ranges of carbon dioxide could have contributed to the preliminary developments and unfold of angiosperm vegetation.