Guanlong wucaii

a, b, Cranial reconstruction in left lateral (a; shaded area indicates the unpreserved portion) and dorsal (b) views. adc, anterodorsal concavity; al, anterior lamina; an, angular; aof, antorbital fenestra; d, dentary; dg, dentary groove; emf, external mandibular fenestra; en, external naris; if, infratemporal fenestra; isf, foramen on ischium; j, jugal; jp, pneumatic jugal foramen; l, lacrimal; m, maxilla; mc I–IV, metacarpals I–IV; mo, maxillary opening; mt I–V, metatarsals I–V; mvc, median vertical crest; nc, nasal crest; obf, obturator foramen; orb, orbit; pf, prefrontal; pfe, pneumatic fenestra; pl, posterior lamina; pm, premaxilla; po, postorbital; pr, pneumatic recess; qj, quadratojugal; ri, right ilium; ris, right ischium; rp, right pubis; sa, surangular; sac, sacrum; sc, sagittal crest; sec, semilunate carpal; sq, squamosal; tp, tubercle on pubis; tr, transverse ridge. Scale bar: 5 cm

Well, I was going to put together more about this beautiful new basal tyrannosauroid from the Jurassic of China, Guanlong wucaii, but Carl Zimmer beat me to it. I’ll just show you that lovely crested skull, and below the fold, a picture of the fossil in situ, and let Carl do the hard work of explaining it all.

(click for larger image)

a, Photograph, b, Line drawing of IVPP V14532. cav, caudal vertebrae; cv, cervical vertebrae; dv, dorsal vertebrae; lm, left manus; rc, right coracoid; rf, right femur; rfi, right fibula; rh, right humerus; ri, right ilium; rm, right manus; rp, right pubis; rpe, right pes; rr, right radius; rs, right scapula; rt, right tibia; ru, right ulna; sk, skull. Scale bar, 8 cm.

Xu X, Clark JM, Forster CA, Norell MA, Erickson GM, Eberth DA, Jia C, Zhao Q (2006) A basal tyrannosauroid dinosaur from the Late Jurassic of China. Nature 439:715-718.


  1. says

    And you can post a sign: “We feed every third salesman to the tyrannosauroid*. The second one just left.”

    *Only a theory.

  2. says

    good points–I am warming to the idea. I bet the Scientologists would think twice about leaving all that unsolicited literature on my door, too.

  3. Graculus says

    yeah, teeth like that are certainly what I’m looking for in a pet.

    I take it you’ve never owned a dog larger than a toaster.

    I have a Rottweiler. I haven’t seen the JWs in years. :-)

  4. Diego says

    My apologies for nitpicking, but this is one of my pet peeves. It’s a basal tyrannosauroid (Tyrannosauroidea) not a tyrannosaurid. P.S. You should see how I grind my teeth when I read “hominid” used as synonymous for “hominin”. ;)

  5. John S Costello says

    It’s looking up! Another dino that died in the flood with its face turned towards God!!!1*

  6. Rocky says

    Exceedingly beautiful animal!
    Haven’t read the threads yet, did they say how old this fossil is?

  7. says

    Graculus, it’s not the size of the teeth, but their properties–dogs, even big one, have incisors and canines in the front and molars in the back. Uniformly fangy-like teeth all the way back are much more a reptile hallmark, cf. alligators and crocodiles. Not a particularly big surprise that this fossil has reptilian teeth, of course, but my imagination finds them much more scary than molars–they can hang on to prey and do a lot more damage a lot more efficiently.

  8. Graculus says

    they can hang on to prey and do a lot more damage a lot more efficiently.

    I have to disagree. Granted, those molars are butchering shears, not piercing fangs, so they do a different type of damage and come into play differently, but you don’t really want to be on the recieving end of a sideswipe from them. That’s plastic surgery time. And prying a large dog loose from something involves persuasion, not force. Our old guy used to enjoy being picked up by his chew toy and swung around in mid-air. Kinda like a furry hammer throw.

  9. says

    To Rocky: this fossil is from the Oxfordian Stage of the Late Jurassic Epoch, so around 160 million years ago.

    RavenT and Graculus: dinosaurs (as most reptiles) don’t have incisors, molars, or canines per se. However, like other tyrannosauroids (but unlike most carnivorous dinosaurs), the teeth at the front of the snout of Guanlong are very different in shape than the lateral teeth. They are like little scrapers, with a shape like a capital U in cross section (okay, a U with a crossbar across the top).

    Hope this helps,

  10. says

    Thanks, Thomas. I wasn’t aware of that–all I know about reptilian dentition comes from modern crocodile skulls in a vertebrate anatomy survey class. So many interesting things to learn that I’ll never get to in my lifetime!

    Graculus, I think we *can* agree that debating whether it’s worse to be mauled by fangs or molars is a race to the bottom either way :). I liked your image of a furry hammer throw.

  11. Da Shu says

    I have just read about this recent discovery in my local newspaper. Since I have been following the bird/dinosaur connection rather closely this struck a new and interesting note. Though no expert in the field, I find it very intersting that most of the new ground breaking finds are coming from China (my current home of record). Why suddenly all the finds in China???? Any ideas?

  12. marc says

    most of the recent news from China comes from the Liaoning province, where Early Cretaceous sites are yielding ridiculously well-preserved fossils of plants and animals buried in fine volcanic ash. Really amazing stuff. haven’t read much about this particular Jurassic formation though.

    That is a pretty vacuous external naris (en) that makes quite a bulge out of the premaxilla (pm). This thing had quite a schnoz, huh?