Confuciusornis: Beast of the Week

This week we will be checking out possibly one of the most well-understood of all the prehistoric dinosaurs.  Check out Conficiusornis sanctus!  Confuciusornis was a prehistoric bird, that lived in what is now China, during the early Cretaceous Period, between 125 and 121 million years ago.  From beak to tail it measured about a foot and a half long, and had a wingspan of a bit over two feet wide.  When alive, Confuciusornis would have eaten meat but also probably ate plant material, possibly seeds, as well.  Its name translates to "Confucius Bird Sage", in reference to Confucius, the famous Chinese philosopher.

Confuciusornis is known from literally thousands of fossilized specimens, which is unheard of when it comes to other dinosaur fossils.  Because of this we know quite a bit about its anatomy and lifestyle.

Confucius fossil pair.  Possibly a male and female. (note the long tail feathers)

First of all, many of the Confuciusornis specimens preserved soft tissue, including feathers.  It had long, narrow primary feathers on the wings and certain individuals had a pair of extremely long, ribbon like feathers growing from their tails.  It has been suggested that Confuciusornis was sexually dimorphic, the males possessing the long ribbon feathers for display.  It is also possible that both sexes had these feathers, and certain individuals were molting (shedding old feathers) at the time of their deaths.  The presence of these feathers also didn't have any correlation with body size, so if it was sex-related, the males and females were the same size as adults.  These tail feathers are interesting in that only the tips demonstrate the classic feather structure with a central shaft, branching off into barbs on either side.

Confuciusornis possessed a large, toothless beak, like modern birds.  However, there were other prehistoric birds that lived after Confusiusornis had gone extinct that still had teeth.  This proves that Confuciusornis evolved its beak independently of those that we see in modern birds.  The beak would have been relatively powerful in life, and many scientists suggest it could have been a seed-eater.  Modern seed-eating birds, like cardinals and sparrows, have similarly shaped beaks.  However, some doubt this since no gastroliths, small rocks swallowed by animals to help digest hard food, like seeds, were ever found in any Confuciusornis specimen. (and we HAVE found them in many other dinosaur fossils) We know Confuciusornis  at least ate small fish, since the remains of one was found in the neck region of one specimen.  This could have been the crop, a pouch in the throat region of birds, used for storing food before swallowing.

The wings of Confuciusornis tell us that this dinosaur probably could fly, but it wouldn't have been as agile in the air as many modern birds are, especially for long periods of time.  We hypothesize this because Confuciusornis doesn't have a very large breastbone, or keel as it's called in birds, for wing muscles to attach.  Keel bones in many modern birds are proportionally huge.  Even the ones on domestic chickens and turkeys are large. (Next time you eat a rotisserie chicken check this out.  It's where the breast meat attaches to the skeleton.)  Confuciusornis also didn't have as wide of a range of motion in its shoulder joints as modern flying birds do, which would have made flapping a bit more difficult for it.  Finally, it's tail lacked the broad steering feathers found in modern birds.  The hands of Confuciusornis had three distinct fingers, tipped with curved claws, which is something else not common in modern birds.

Confuciusornis life reconstruction showing some display behavior by Christopher DiPiazza.

Lastly, scientists may have figured out what color Conficiusornis' feathers were!  Since the fossilized feathers were so well preserved, scientists were able to look at them under a powerful microscope and see the shapes of melanosomes, organelles that give color to a feather.  Even though the color, itself, wasn't visible, the shape of the organelle would reflect the pigment that would have been there in life.  By comparing these shapes to those of modern bird feather melanosomes, they were able to conclude that Confuciusornis likely had a dark gray body, black tail feathers, and possibly white primary feathers.  However, it should be noted that not ALL kinds of melanosomes necessarily preserved, so an overlapping of different kinds of these organelles may have yielded a different coloration in certain areas.

That is all for this week!  As always feel free to comment below or on our facebook page!

References

Chiappe, Luis M., Shu-An, Ji, Qiang, Ji, Norell, Mark A. (1999) "Anatomy and systematics of the Confuciusornithidae (Theropoda:Aves) from the Late Mesozoic of northeastern China" "Bulletin of the American museum of Natural History no.242 89pp.

Elzanowski, A. (2002) "Biology of basal birds and the origin of avian flight". In: Zhou Z., Zhang F. (eds) Proceedings of the 5th Symposium of the Society of Avian Paleontology and Evolution, Beijing, 1–4 June 2000. Science, Beijing, pp 211–226

Wogelius, R.A., Manning, P.L., Barden, H.E., Edwards, N.P., Webb, S.M., Sellers, W.I., Taylor, K.G., Larson, P.L., Dodson, P., You H., Da-qing L., and Bergmann, U. 2011. Trace metals as biomarkers for eumelanin pigment in the fossil record. Science, 333(6049): 1622-1626.

Zhou Z. and Farlow, J.O. (2001) "Flight capability and habits of Confuciusornis". In: Gauthier and Gall (eds). New perspectives on the origin and early evolution of birds: proceedings of the international symposium in honor of John H. Ostrom. Peabody Museum of Natural History. Yale University, New Haven. pp. 237–254