Redondasaurus (and not Leptosuchus)

A non-ornithodire! Woo. Still a short post though, sorry. This is a superb mount of Leptosuchus (errr, well I think so, forgot to check) Redondasaurus (though see the comments thread) from the Triassic section of the Carnegie. It is nice to see things other than the dinosaurs and pterosaurs (or icthyosaurs and plesiosaurs for that matter) get a look in, and this was something I’d never seen before. Oddly enough I have a nice schematic of the skull that I stole form somewhere years ago that I use in a lecture to emphasise some of the issues in creating characters in cladistic analyses and convergences.

This does have a pretty crocodilian-like snout and is certainly a good candidate for a classic piece of convergence in morphofunction. But here it is the premaxilla that has elongated, whereas crocs generally have a short premaxilla and most of the elongation comes from a long maxilla. Thus there is a clear difference in the manner in which the lengthening has happened. And from a cladistic point of view therefore, there is a big difference between a character along the lines of “elongate snout” and “elongate maxilla”, the former unifying the two, the latter separating them.

7 Responses to “Redondasaurus (and not Leptosuchus)”

  1. 1 Manuel 27/11/2011 at 2:35 pm

    The size and shape of the mandibular fenestra calls my atention..
    do you know any study of phytosaur musculature?
    because interpretation of the skull musculature could help in the way to resolve such convergences between crocs and his old uncles..

  2. 3 Jura 27/11/2011 at 7:19 pm

    Minor quibble, the guy in the picture from the Carnegie is actually Redondasaurus. The Carnegie display is really sweet as it seems to be one of the few non-dinosaur displays that portrays the animal in an active pose.

  3. 4 220mya 27/11/2011 at 8:57 pm

    Manuel – its quite old, but there is a study of phytosaur cranial musculature:

    Anderson, H.T. 1936. The jaw musculature of the phytosaur, Machaeroprosopus. Journal of Morphology 59(3):549–587.

    Jura – I think the mount is meant to represent Redondasaurus, but I believe most of it is based off of the Smilosuchus (previously Leptosuchus) mount that is at Petrified Forest National Park, New Mexico Museum of Natural History & Science, and Ghost Ranch Ruth Hall Museum of Paleontology. This mount is based off of material from the University of California Museum of Paleontology.

    • 5 David Hone 27/11/2011 at 9:07 pm

      Thanks for the info both of you. I’ve been trying to hunt down a photo of the sign or something on the Carnegie website to verify this and based on unconfirmed sources it does indeed seem to be (or is supposed to be) Redonda, so I’ve changed the post title.

    • 6 Manuel 28/11/2011 at 3:03 pm

      Many thanks 220mya ! I´ll try to find it =D

  4. 7 Larry Rinehart 13/01/2012 at 6:21 pm

    It is Redondasaurus bermani (after Dave Berman at the Carnegie). We (New Mexico Museum of Natural History) built the the Carnegie mount and one of our own, which is a much more dynamic pose – leaping out of the water – Nile corocdile style at a placeras. The skull is a composite of two specimens; a huge skull missing its distal snout and an isolated snout of the same genus, found right across a wash from the big skull. The jaw is another specimen that just happened to fit. All the ribs, gastralia, limb-hand-foot bones, most hip and shoulder bones, many of the vertebrae and scutes are NMMNH specimens from northern and eastern NM. The remainder of the verts and chevrons were cast in plaster, shaped with a belt sander and textured using latex pads peeled off of other real bones.They were then recast in resin. Hope this helps clarify…

    Larry Rinehart, preparator at NMMNH

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