Sunday, June 15, 2014

Citipati: Prehistoric Animal of the Week

Hello all!  Happy Fathers Day!  This week we will be keeping good fathers in mind as we take a look at a dinosaur who's remains completely changed the way we looked at not only it, but dinosaurs as a whole as well.  Check out Citipati osmolskaeCitipati was an oviraptorid theropod that lived in what is now Mongolia during the late Cretaceous, roughly 75 million years ago.  It was a fairly large oviraptorid, measuring about ten feet long from beak to tail, and would have eaten meat and possibly some plant material as well.  Citipati's habitat would have been a desert where it coexisted with other dinosaurs such as Protoceratops, Velociraptor, and Oviraptor.

Citipati family goes for a stroll.  Mom leads the way while Dad takes up the rear, making sure none of the kids do anything stupid.

The name, Citipati, translates to "funeral pire lord" and is a reference to a Tibetan folk story.  In the story, two monks were decapitated while they were meditating.  Often times these two monks are depicted in traditional Tibetan art as two skeletons dancing around in fire, called citipati.  Citipati, the dinosaur, is known from many beautifully preserved skeletons and is named in reference to these depictions.

Even in death these guys kept partying.  Good for them.
  
Citipati was an oviraptorid and belonged to the same general family as Oviraptor and Anzu. Like them, it had a short snout and tall beak.  This beak would have been backed up by extremely powerful muscles which would have enabled this animal to bite down HARD in life.  Like its relatives it possessed no teeth in its mouth, but it did have pointed bone structures on the roof of its mouth that were used to crack...something.  It had a particularly long neck and short tail amongst other members of its family.  It also had a bony crest on the front of its snout.  In life, Citipati, would have had feathers.

Citipati skeletal mount.

Now here is where Citipati gets even more interesting.  Remember last Easter when I talked about Oviraptor and how its name means "egg thief" because it was found near some eggs but the eggs turned out to be its own thanks to another related specimen that was found sitting on a nest of similar looking eggs?  ...Well Citipati was that related specimen!  Back in the 1990s paleontologists discovered the remains of a Citipati that was sitting on a nest of eggs in the exact pose that birds today assume when they brood their own eggs.  It's actually quite beautiful and tragic if you think about it.  This poor parent dinosaur's instincts were so strong that it remained on its nest even if it meant being swallowed up by a sandstorm.  The result is a fossil that gave scientists more information about dinosaurs as a whole, let alone Citipati, than they ever could have imagined!

Famous brooding Citipati fossil display at the American Museum of Natural History in New York.  You can make out how the animal would have been sitting with its legs folded in the middle and its arms spread over the eggs when it died.

So what exactly can we gather from this Citipati fossil?  Like I stated before, upon looking inside some of the eggs, and by comparing them to other eggs that have been found in the area, it was concluded that Citipati and its kin were caring parents and totally undeserving of their "egg thief" name.  (Although they may have eaten the eggs of other dinosaurs too even though no evidence suggests it as of now...eggs are nutritious!)  It also solidified the modern bird's connection to other dinosaurs thanks to the pose this parent had died in.  The last bit of information wasn't so obvious.  If you look at the fossil, you will notice that the parent's body with the arms out to the sides still doesn't completely cover the eggs as it is.  If it had arm feathers, however, all the eggs would have been perfectly guarded under a nice, plumed roof...just like modern birds.  This fossil, even though no actual feathers were preserved, brought us that much closer to the eventual realization that many theropod dinosaurs had feathers in life.

So what does this all have to do with Fathers Day?  Well, it is often assumed that the Citipati sitting on the nest was a female.  But what if it was the male?  There sadly isn't any evidence that favors the adult specimen being either sex.  If we look at living dinosaurs that have similar lifestyles as Citipati may have had, however, we do see some hints.  I'm talking about large flightless birds like ostriches, emus, cassowaries, and rheas.  (I actually get to see rheas every day at work at the zoo.  They are nothing short of living dinosaurs!)  Many of these kinds of birds are what we call polyandrous.  That means one female will mate with multiple males.  In the case of both ostriches and rheas, it is the males who build nests.  Then the female goes around to each one and deposits some eggs. (not all of which are necessarily from that particular father)  Each father then proceeds to brood the clutches much in the same way the Citipati was found doing to its own millions of years ago.  When the babies hatch out, father raises them until they are old enough to be independent.  Yay for dinosaur dads!

That's dad!  The male ostriches have the striking black and white feathers.  Females are brown.

Am I saying that the Citipati found on the nest was definitely a male?  No.  I am saying that we don't know and assuming it was dad and not mom is as good a guess as any right now, especially when you look at the modern evidence.

That's all for this week!  Happy Fathers Day to all the dads out there!  If you have any requests or comments please do so below or on our facebook page

References

Clark, J.M., Norell, M.A., & Barsbold, R. (2001). "Two new oviraptorids (Theropoda:Oviraptorosauria), upper Cretaceous Djadokhta Formation, Ukhaa Tolgod, Mongolia." Journal of Vertebrate Paleontology 21(2):209-213., June 2001.

Norell, M.A., Clark, J.M., Chiappe, L.M., and Dashzeveg, D. (1995). "A nesting dinosaur." Nature 378:774-776.

Norell, M. A., J. M. Clark, D. Dashzeveg, T. Barsbold, L. M. Chiappe, A. R. Davidson, M. C. McKenna, and M. J. Novacek (1994). "A theropod dinosaur embryo, and the affinities of the Flaming Cliffs Dinosaur eggs." Science 266: 779–782.

Osborn, H.F. (1924). "Three new Theropoda, Protoceratops zone, central Mongolia." American Museum Novitates, 144: 12 pp., 8 figs.; (American Museum of Natural History) New York. (11.7.1924).

Varricchio, D.J. (2000). "Reproduction and Parenting," in Paul, G.S. (ed.). The Scientific American Book of Dinosaurs. New York: St. Martin's Press, pp. 279-293.

1 comment:

  1. It has even been seriously suggested in the scientific literature that the brooding oviraptorosaur specimens are male, though the methods used to infer this have been subsequently questioned.

    ReplyDelete