Saturday, May 7, 2011

Lukousaurus in Nesbitt's matrix

Back in ye olde days when I was new to the DML, I wrote a post on Lukousaurus to determine its phylogenetic affinities- .  I didn't have anywhere near the amount of knowledge and resources I do now, and I considered it an abelisaurid or sphenosuchian.  Times have changed and now we have Nesbitt's huge new analysis which is perfect for coding Lukousaurus in.  It doesn't have abelisaurids, but does have Dilophosaurus and Allosaurus along with several sphenosuchians.  Note the caveat that Lukousaurus is coded from Young's 1948 figures and description.  So after entering Lukousaurus, there are 4683 MPTs with Lukousaurus as an archosaur in all of them.  It is not a member of Ornithosuchidae, Revueltosaurus+Aetosauria, Poposauroidea, Loricata or Dinosauromorpha.  So it's probably some sort of basal pseudosuchian...

By the way, I noticed when coding that as in Smith et al.'s matrix, Marasuchus is not coded for its maxilla, even though Nesbitt lists the specimen as one of those he used for scoring, and lists the maxilla's presence in the material.  Also Coelophysis is oddly coded for osteoderm character 408, despite lacking osteoderms.

More added taxa to follow...


  1. True Mickey, Lukousaurus seems at first glance more like a dinosaur than a sphenosuchian.

    The interesting thing about making a wrong diagnosis is that over time you gain more experience and you become smarter.

    I think we all learn more from mistakes than successes.

    All the end is a process that never ends.

    1. Knoll et al. (2012) find Lukousaurus very similar to suchian archosaurs in the size and shape of the antorbital fossa, concurring with Irmis (2004) that Lukousaurus is not a theropod dinosaur or even a dinosauromorph.

      R. B. Irmis. 2004. First report of Megapnosaurus (Theropoda: Coelophysoidea) from China. PaleoBios 24(3):11-18.

      Knoll F., Rohrberg K. 2012. CT scanning, rapid prototyping and re-examination of a partial skull of a basal crocodylomorph from the Late Triassic of Germany. Swiss Journal of Geosciences 105:109–115.

  2. There is some tangential evidence Coelophysis may have had osteoderms based on some Ghost Ranch material. It has never been published and I am not terribly convinced of it - the supposed osteoderms have not, as far as I know, been found in unequivocal life position on/near a Coelophysis.