Episode 448: The Dinosauroid (the human-troodontid hybrid)


Episode 448: The Dinosauroid (the human-troodontid hybrid). Troodon was a brooder, a neuroscientist’s tackle if dinosaurs may develop into as good as people, and dinosaur extinction arguments


  • A neuroscientist’s tackle whether or not dinosaurs may evolve to be as clever as people supply
  • The controversy on what made the dinosaurs go extinct continues, with extra arguments in favor of the Chicxulub impression supply
  • Troodon may change its physique temperature and certain brooded its eggs in nests shared with different females of the identical species supply


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Paleo Pins: Diversity Expansion

The dinosaur of the day: Stenonychosaurus

  • Troodontid theropod that lived within the Late Cretaceous in what’s now Alberta, Canada (Dinosaur Park Formation)
  • Presumably additionally discovered within the Two Drugs Formation
  • Appeared like different small theropods, with a protracted tail, in all probability coated in feathers, an s-curved neck, brief arms, lengthy legs, and as a troodontid, had sickle-shaped claws on the second toes of every foot
  • Estimated to be about 8.2 ft (2.5 m) lengthy and weigh 77 lb (35 kg)
  • Had lengthy, slender legs, so could have been a quick runner
  • Tail was versatile on the base, which can have helped it flip whereas strolling or operating
  • Had giant eyes and binocular imaginative and prescient
  • In a position to grasp and maintain objects
  • Presumably reached grownup dimension at three to 5 years previous, primarily based on a troodontid present in Two Drugs Formation
  • Presumably was an omnivore
  • Enamel have been completely different in comparison with different theropods
  • Had jaws just like an iguana’s (which eats crops), and the tooth had giant serrations
  • In 1988 Tom Holtz and Daniel Brinkman discovered that troodontid tooth had bigger denticles than different theropods, and that the serration scaling is what made it so complicated on classify Troodon when it was first described
  • Stenonychosaurus and Troodon have been lumped and cut up previously, and Troodon was named from a single tooth, in 1856 (a part of why it’s complicated)
  • Talked about Troodon in episode 36
  • Urged Troodon would have additionally eaten eggs and invertebrates (like worms), and others have instructed troodontids ate bugs
  • Kind and solely species is Stenonychosaurus inequalis
  • Genus title means “slender claw lizard”
  • Named by Charles M. Sternberg in 1932
  • Sternberg described a left foot, elements of a hand, and a few tail vertebrae
  • In 1932, Sternberg wrote: “Observant collectors and college students of vertebrate paleontology, who’ve studied the Stomach River and Edmonton faunas totally understand that, despite the various advantageous dinosaurian specimens which have been collected from these beds in recent times, many kinds are nonetheless imperfectly identified. Maybe the light-limbed theropods are among the many least identified of those dinosaurs”
  • Sternberg discovered Stenonychosaurus to carefully resemble Ornitholestes, however Stenonychosaurus was larger and had some variations within the tail and ft
  • Additionally wrote: “The construction of each the entrance and hind ft of Stenonychosaurus appears to counsel that it ought to be considered a direct descendant of Ornitholestes although the distinction within the caudal vertebrae could be towards this suggestion” (ended with want to search out extra full specimens/extra fossils to study extra)
  • Over time, Stenonychosaurus has been reassigned and reclassified
  • Russell had at one level synonymized Polyodontosaurus and Ornithomimus altus as Stenonychosaurus however mentioned there wasn’t sufficient proof to synonymize with Troodon
  • Carpenter later synonymized Polyodontosaurus, Stenonychosaurus, Ornithomimus altus, and Troodon formosus as Saurornithoides inequalis
  • Currie synonymized Stenonychosaurus and Pectinodon beneath Troodon formosus
  • Phil Currie discovered that variations within the tooth and jaws of troodontids have been primarily based on age and place of the tooth within the jaw, as a substitute of being a characteristic of various species. He reclassified Stenonychosaurus as Troodon, and reclassified different troodontids as Troodon formosus
  • Later, different scientists, together with Currie, thought there could also be extra troodontid species. Ended up splitting out Dinosaur Park Formation fossils that was once Stenonychosaurus as Troodon inequalis
  • In 2011, Lindsay Zanno and others analyzed how troodontids have been categorized, and located all of the specimens assigned to Troodon formosus have been in all probability completely different species, and for the reason that holotype of Troodon is a tooth, Troodon could also be a nomen dubium
  • In 2017, Evans and others agreed that the holotype of Troodon was not distinctive sufficient and instructed reviving Stenonychosaurus for troodontid fossils present in Dinosaur Park Formation
  • In 2017, Aaron van der Reest and Phil Currie discovered Troodon formosus to not be legitimate
  • Studied a troodontid pelvis van der Reest had present in 2014 in Dinosaur Provincial Park, which led him to inspecting troodontid cranium fossils
  • Led to him and Phil Currie resurrecting Stenonychosaurus inequalis and naming Latenivenatrix mcmasterae
  • They reassigned plenty of the Stenonychosaurus fossils to a brand new dinosaur, Latenivenatrix
  • Coated in episode 144
  • Talked about the way it appeared unlikely for all these fossils to belong to Troodon, as a result of that might imply it spanned 15 million years and has been present in what’s now Mexico all the way in which as much as Alaska
  • A 2021 examine by Thomas Cullen and others discovered that Latenivenatrix was really a junior synonym to Stenonychosaurus (the variations in options have been as a result of particular person variation)
  • In 1969 Dale Russell described a extra full Stenonychosaurus skeleton. This skeleton was the idea for a life-sized sculpture of Stenonychosaurus, and a sculpture of the well-known “dinosauroid”
  • In 1982, Russell & Séguin did a thought experiment on what Stenonychosaurus would seem like if it had continued evolving till immediately
  • In 1982, Russell and Séguin wrote: “Stenonychosaurus was a extremely progressive animal for its day”
  • Stated: “It may also be entertaining to take a position in a qualitative method on how the descendants of S. inequalis might need appeared had they survived the terminal Mesozoic extinctions” and advanced to have an EQ just like people
  • Stated that over time, the EQ (encephalization quotient), relative mind weight in comparison with physique weight, in dinosaurs elevated
  • Discovered that whereas a Troodontid cranium had a low EQ in comparison with a human, it was lots greater in comparison with different dinosaurs
  • Had a big mind, particularly in comparison with different dinosaurs
  • Urged that if Stenonychosaurus advanced till immediately, may have an EQ just like a human’s
  • Thought the big mind would result in a shorter face, and would ultimately be toothless and have a brief neck to assist the bigger mind, and ultimately stroll like a human, and have {a partially} opposed finger on every hand (because it may grasp)
  • Being upright would additionally imply no extra tail, or a stump of a tail
  • This Dinosauroid appeared very human like
  • May additionally argue it appeared like a sci-fi alien, with giant eyes
  • Russell and Séguin argued that people have one of the best physique form for our large brains, which is why Stenonychosaurus would probably evolve to look extra human, but in addition allowed that they might be biased
  • Imagined this Dinosauroid would give dwell beginning as a substitute of lay eggs (for the mind energy/bigger brains and heads) and feed regurgitated meals
  • Ended the paper with: “The presence of this physique kind in Homo sapiens demonstrates that the answer exists. It might, nonetheless, not be distinctive. We invite our colleagues to establish alternate options”
  • Thought experiment has had a number of criticism, for the Dinosauroid being too human-like (some scientists have mentioned it will maintain its theropod physique, and be extra horizontal than vertical, with a protracted tail)
  • Attainable that eggs and nests present in Two Drugs Formation in Montana belong to Stenonychosaurus (has been considered Orodromeus, then later Troodon, then Van der Reest and Currie mentioned it was presumably Stenonychosaurus)
  • Lived on a heat coastal floodplain coated by forests
  • Different dinosaurs that lived across the identical time and place embrace Daspletosaurus, Gorgosaurus, Lambeosaurus, Corythosaurus, Prosaurolophus, Styracosaurus, Centrosaurus, Chasmosaurus, Scolosaurus, Euoplocephalus, Edmontonia, Stegoceras, and Foraminacephale

Enjoyable Truth:

Most dinosaurs by no means obtained the possibility to see a butterfly, however some did!

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