Novel insights – part 5

Earlier here, here, here and here we looked at novel insights recovered from the large reptile tree. Today we’ll continue and finish with derived archosauromorphs in part 5.

New archosauromorpha

  1. Euarchosauriforms (sans parasuchia and proterochampsidae) start with Euparkeria,  derived from the FMNH specimen of Youngoides, which has a small antorbital fenestra.
  2. Vjushkovia is a basal rauisuchid.
  3. Decuriasuchus is not a rauisuchid, but a pre-archosaur/pre-poposaur derived from basal rauisuchids like Vjushkovia.
  4. Ticinosuchus has a sharp triangular premaxilla and is basal to the aetosaurs.
  5. A menagerie of archosauriformes, Arizonasaurus, Yarasuchus, Qianosuchus, TicinosuchusStagonolepis and Aetosaurus form a clade.
  6. Lotosaurus is not related to Arizonasaurus, but to Silesaurus.
  7. Poposaurs include Turfanosuchus at the base.
  8. Gracilisuchus is a basal archosaur/crocodylomorph. Archosaurs include crocs and dinos and that’s all.
  9. The calcaneal heel appeared and disappeared several times.
  10. Protodinosaurs include PVL 4597, Lewisuchus, Pseudhesperosuchus and Trialestes, not pterosaurs, Lagerpeton or Marasuchus.
  11. Marasuchus is a basal theropod.
  12. Phytodinosauria is a clade including Eoraptor, Sauropodomorpha and Ornithischia.
  13. Damonosaurus Jeholosaurus and Chilesaurus are basal ornithischians.
  14. The pubis of Pisanosaurus was rotated during taphonomy. When repaired it looks like a standard ornithischian partial pelvis.
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2 thoughts on “Novel insights – part 5

  1. The Pisanosaurus pubis issue is an easy example of why most of these aren’t “insights.” It’s your hypothesis that the pubis was taphonomically rotated, but there’s no actual evidence for it. Indeed, the fact the femoral head is still inside the acetabulum would suggest there’s no major disarticulation. Then there’s the fact your reconstruction creates a gap between the pubis and ischium that the standard interpretation doesn’t. Also, would I be wrong to guess you then coded Pisanosaurus as if it had an opisthopubic pelvis with pubis and ischium switched, turning your at best speculative idea into hard data used by PAUP?

    By the way, the most recent examination of Pisanosaurus suggests it’s actually a silesaur, as it shares ankylothecodonty and lacks some dinosaurian characters (Agnolin, 2015). So we would expect it to have a propubic pelvis. Ironically, back in 2013 you had Pisanosaurus as sister to poposaurs+silesaurs, which would have been an “insight” then. How many of your current “novel insights” will still exist in 2017?

  2. Interesting thoughts on Pisanosaurus. Let’s take a look! How many of my novel insights will still exist in 2017? I eagerly look forward to having them all overturned — if that’s the way the ball rolls.

    Added minutes later:

    Pisanosaurus distinct from Silesaurus in the current scoring
    (let me know if any of these are in error):

    constricted snout

    posterior jaw line descends, based on mandible

    blunt teeth, not constricted at base

    surangular terminates not anterior to coronoid

    dentary contributes to cornoid process

    mandibular fenestra not present

    posterior mandible deeper anteriorly

    retroarticular angle straight

    cervicals decrease anteriorly

    mid cervical shorter than mid dorsal

    cervical centra parallelogram in lateral view

    five or more sacrals

    acetabulum perforated

    prepubic process on pubis (based on pubic rotation, and if you leave it alone you don’t get a Silesaurus-like pelvis)

    fibula trochanter absent

    fibula diameter greater than half the tibia

    metatarsals 2-4 not shorter than half the tibia

    pedal 4 length shorter than mt 4

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