Episode 436: How dinosaurs turned birds replace. Plus dinosaurs of the day Ornithomimus
Information:
- An replace on how dinosaurs turned birds, by on the lookout for the evolution of the entrance of their wing supply
- Sauropod professional Michael Taylor et. al have a superb paper in regards to the concrete Diplodocus of Vernal, Utah supply
- Mattel is relaunching Barney as an animated collection in 2024 supply
- The Chickenosaurus mission—making a non-avian-looking dinosaur from rooster embryos—is caught at rising a tail supply
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The dinosaur of the day: Ornithomimus
- Ornithomimid theropod that lived within the Late Cretaceous in what’s now North America (Canada and the U.S.)
- Regarded considerably like an ostrich
- Walked on two ft
- Had a small head
- Had a comparatively brief torso
- Physique coated in feathers, and had a small, toothless beak
- Could have been an omnivore
- Had three toes on every foot, lengthy arms, and an extended s-curved neck
- Had hole bones, and was a quick runner
- Had massive eyes and a big mind
- Most likely had good imaginative and prescient
- Giant mind might have helped it transfer quick
- Had straight hand and foot claws
- Fingers had been about the identical in size
- Fingers regarded sloth-like, and Henry Osborn thought they might have used their arms to hook branches when consuming
- As for measurement, there are two species of Ornithomimus and so they range in measurement
- Gregory Paul estimated in 2010 Ornithomimus edmontonicus was about 12 ft (3.8 m) lengthy and weighed 370 lb (170 kg)
- Ornithomimus velox was about 20% smaller
- Two species: Ornithomimus velox (sort species) and Ornithomimus edmontonicus
- Genus title means “hen mimic”
- Genus title refers to its bird-like foot
- Charles Marsh named Ornithomimus velox in 1890, based mostly on a foot and a part of a hand present in Colorado, US
- Species title velox means “swift”
- When Marsh first described Ornithomimus, he in contrast it to ostriches and turkeys
- Fossils first present in 1889 by George Lynman Cannon
- Fossils discovered close to a small white faculty home with rooster coops round it
- Seventeen species had been named Ornithomimus, however most of them have been reassigned to a different genera or they’re thought-about to be doubtful
- Marsh, in the identical paper he named the sort species, named Ornithomimus tenuis and Ornithomimus grandis, based mostly on fragmentary fossils John Bell Hatcher present in Montana (grandis now regarded as tyrannosauroid fossils)
- Marsh additionally named Ornithomimus sedens in 1892 based mostly on a part of foot (now regarded as alvarezsaurid materials)
- Lawrence Lambe named Ornithomimus altus in 1902 based mostly on hindlimbs present in Alberta, however this turned Struthiomimus in 1916 (talked about Struthiomimus in episode 270)
- Different Ornithomimus species which might be now not legitimate embody O. minutus, O. affinis, O. brevitertius, O. samueli, O. mirandus, O. elegans, O. asiaticus. O. lonzeenis, O. currellii, and O. ingens
- Charles M. Sternberg named the second legitimate species, Ornithomimus edmontonicus in 1933, based mostly on an almost full skeleton discovered within the Horseshoe Canyon Formation of Alberta, Canada
- For years, it was exhausting to tell apart Ornithomimus from Struthiomimus
- In 1972, Dale Russell did a research that discovered the variations between the 2, and likewise discovered Ornithomimus velox and Ornithomimus edmontonicus to be legitimate, after which reassigned the opposite species and created new genera, together with Dromiceiomimus (“emu mimic”)
- Struthiomimus had an extended torso and longer arms
- Russell additionally mentioned it was exhausting to inform the distinction between Ornithomimus velox and Ornithomimus edmontonicus
- Donald Baird and Jack Horner in 1979 thought that two tibiae (leg bones) present in New Jersey by Joseph Leidy in 1865 had been Ornithomimus, and so they named it Ornithomimus antiquus
- Initially the bones had been named Coelosaurus antiquus, however Baird and Horner discovered the title Coelosaurus was already in use for a doubtful animal (named based mostly on one vertebra). That animal was named by an nameless writer in 1854, and we now know the writer was Richard Owen
- Baird referred extra specimens present in New Jersey and Maryland to Ornithomimus antiquus
- In 1997, Robert Sullivan discovered Ornithomimus velox and Ornithomimus edmontonicus to be junior synonyms of Ornithomimus antiquus (discovered velox and edmontonicus to be tough to inform aside, and so they each shared options with antiquus)
- In 2004, David Weishampel discovered Ornithomimus antiquus (Coelosaurus antiquus) to be a nomen dubium
- Since then there was extra lumping and splitting, together with between Ornithomimus and Dromiceiomimus
- In 2015 Leon Claessens and Mark Loewen redescribed Ornithomimus velox
- Totally ready the holotype (they weren’t absolutely ready earlier than), and 3D scanned and did photogrammetry
- “Apparently, lots of Marsh’s printed drawings of O. velox illustrate anatomical element that was not seen till its latest preparation, and a number of other of the main points of those obscured components in his illustrations are deceptive and incorrect”
- Holotype is probably going skeletally mature
- Discovered that the Marsh’s referred specimen was additionally a part of the holotype (identical particular person)
- Ornithomimus velox foot was extra strong than Ornithomimus edmontonicus
- Due to its small measurement, particularly in comparison with different ornithomimosaurs, mentioned “O. velox might characterize the primary occasion of nanism on this group”
- 4 Ornithomimus edmontonicus specimens have been discovered with feathers
- Feather imprints had been present in sandstone
- Two of them are adults with traces of feathers on the arms, and one is a juvenile with feather impressions protecting the decrease again, legs, and neck
- Two of the adults extra complicated feathers on the arms, which suggests the feathers modified as Ornithomimus grew up
- Juvenile was coated in filamentous sort feathers
- The fourth specimen had feathers alongside the tail that had been crushed and distorted, however regarded similar to the feathers of an ostrich. Additionally had pores and skin impressions, which confirmed no scales on the mid-thigh to the ft, and a flap of pores and skin connecting the torso to the higher thigh (additionally just like ostriches)
- A 2012 research discovered Ornithomimus edmontonicus to be coated in feathers in any respect ages (progress levels)
- Discovered the patterns on the feathers to be just like ostriches
- Primarily based on the feather patterns and the naked pores and skin on the legs being just like ostriches, most likely used each for thermoregulation
Enjoyable Truth:
Not all “tyrant” dinosaurs had been large, the household Tyrannidae contains dinosaurs one millionth the dimensions of T. rex.
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