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I Know Dino Podcast Present Notes: Coelurus (Episode 56)


    Episode 56 is all about Coelurus, the primary named small theropod discovered within the Morrison Formation.

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    On this episode, we focus on:

    • The dinosaur of the day: Coelurus
    • Title means “hole tail” (has hole tail vertebrae)
    • Just one legitimate species; sort species C. fragilis (Charles Marsh described in 1879)
    • Kind species was a partial skeleton (a lot of the legs and arms, partial pelvis); skeleton now housed within the Peabody Museum of Pure Historical past; discovered within the Morrison Formation
      Extra bones present in 1980 (in Wyoming and Utah)
    • First named small theropod from the Morrison formation
      Charles Marsh solely described the vertebrae from the again and tail, present in the identical space as the sort specimen of one other genus/species he named, Camptonotus dispar, later renamed Camptosaurus, as a result of the title Camptonotus was already used to explain a kind of cricket
    • Marsh described it as an “animal about as massive as a wolf, and doubtless carnivorous”, although he was unsure it was a dinosaur at first. He described it extra in 1881 and created some illustrations, and labeled it within the new order Coeluria and household Coeluridae
    • A lot of confusion and totally different species named and moved out of the genus
    • Coelurus has been grouped with compsognathids, tyrannosaurids, and at the same time as basal maniraptorans. Typically it’s thought-about it’s circle of relatives, Coeluridae
    • For some time, Coeluridae and Coelurosauria have been wastebasket taxons for small theropods
    • C. fragilis skeleton was scattered, and fossils discovered between Sept. 1879 and Sept. 1880. A number of the bones discovered, Marsh labeled as a brand new species, C. agilis, primarily based on fused pubic bones he believed have been a part of an animal 3 times bigger than C. fragilis
    • In 1888 Marsh named C. gracilis, primarily based on a single claw bone from a small theropod that lived within the Early Cretaceous (present in Maryland); not accepted although
      Cope additionally named some species in Coelurus (even with Bone Wars); he named C. bauri and C. longicollis (from Triassic, New Mexico),; however then put them in their very own genus, Coelophysis
    • Henry Fairfield Osborn named Ornitholestes in 1903, primarily based on a partial skeleton. In 1920, Charles Gilmore stated Ornitholestes and Coelurus have been synonyms, which scientists believed till John Ostrom’s examine in 1980
    • Ostrom confirmed the variations between Ornitholestes and Coelurus, and confirmed that C. fragilis and C. agilis have been the identical (as Gilmore had thought)
    • Dale Russell thought C. agilis was a species of Elaphrosaurus, primarily based on incomplete data, however Ostrom confirmed that wasn’t true. Additionally confirmed that one of many three C. fragilis vertebrae Marsh had illustrated was a composite of two vertebrae
    • Additionally generally confused with Tanycolagreus (Coelurus, Ornitholestes and Tanycolagreus have been greatest recognized small theropods from the Morrison Formation); however Coelurus and Ornitholestes have been higher described (Coelurus had longer again and neck, and longer, extra slender legs and toes than Ornitholestes)
    • In 1995, a partial skeleton within the Morrison Formation was considered Coelurus, however a examine confirmed it was a distinct genus, Tanycolagreus
    • Six species have been named to Coelurus. Along with C. bauri and C. longicollis, there was C. daviesi (Richard Lydekker named in 1888 primarily based on a neck vertebrae from England, however later was named its personal genus, Thecocoeulurus
    • Additionally C. gracilis in 1888 (primarily based on limb stays) however Gilmore reviewed the species in 1920 and solely discovered a single claw (proposed it was Chirostenotes), however now thought-about doubtful
    • When Ornitholestes was thought-about synonymous to Coelurus, it’s sort species was named C. hermanni
    • Coelurus lived in Jurassic
    • Small, bipedal, with lengthy legs (quick)
      Velocity was protection from bigger theropods
    • Round 29-44 lb (13-20 kg)
    • About 7.9 ft (2.4 m) lengthy
    • Carnivore
    • Coelurus ate small prey (bugs, mammals, lizards), and was quicker than Ornitholestes
    • Lengthy neck, doubtlessly slender cranium
    • Not a lot recognized in regards to the cranium, besides a part of the decrease jaw (present in identical space as recognized Coelurus bones, and has some similarities, however may be very slender, which suggests it’s not a part of the identical recognized Coelurus skeleton
    • Lengthy, low vertebrae; neck vertebrae had many hole areas (therefore its title)
    • Morrison Formation was semiarid with flat floodplains.
    • Vegetation included conifers, ferns
    • Different dinosaurs discovered embrace Ceratosaurus, Allosaurus, Apatosaurus, Diplodocus, Stegosaurus
    • Coeluridae is a household of small, carnivorous dinosaurs that lived within the Jurassic
    • In 2003 O.W.M. Rauhut grouped Coelurus, Compsognathus, Sinosauropteryx, and an unnamed Compsognathus-like dinosaur into Coeluridae
    • In 2007 Phil Senter advised Coelurus and Tanycolagreus have been the one coelurids, and have been really tyrannosauroids(was a wastebasket taxon for some time) Dinosaurs that have been within the “wastebasket taxon” and since reclassified embrace Laevisuchus, Microvenator (relative of oviraptorid)
    • Coelurosauria contains different theropod teams now, together with alvarezsaurs, ornithomimosaurs, therizinosaurs, dromaeosaurs, and tyrannosaurs (although at first solely included small theropods); nonetheless numerous questions over how Coelurus genus was associated to others
    • Enjoyable reality: Out of the 188 confirmed impression craters within the Earth Affect Database, the Chicxulub crater on the Yucutan penninsula is the second largest, and the most important within the final two billion years