Friday, October 29, 2010

Resolving dinosaur phylogenies with fossil evidence of protofeathers

According to this article in Nature, a dinosaur skeleton was found in western Liaoning Province, China, that shows evidence of feathers.

Figure 1: Overview of a Tianyulong confuciusi skeleton.

What makes this particular find of a feathered dinosaur important is that it extends the known time period and geographic range of feathered dinosaurs. All previous records list feathered dinosaurs as living in Africa in the early Jurassic period. Now we know that they were also living in Asia, and were around all the way up to the early Cretaceous.

Figure 2: Close-up on evidence of protofeather structures.

This fossil of Tianyulong confuciusi (see figure 1 above) is an incomplete skeleton, but nevertheless it was detailed enough to conclusively prove that feathered dinosaurs (see figure 2 above) lived from the early Jurassic period to the early Cretaceous period, and in an area from Africa to Asia.

Finding this fossil also resolved the dispute over phylogeny. Tianyulong is closely related to Heterodontosaurus and Echinodon.  (See figure 3 below.)

Figure 3: The resolved phylogeny (or at least more resolved than before).

The filamentous integumentary structures are clear evidence that these dinosaurs had protofeathers. However, Zheng suggests that these feathers were geared more towards multicolored displays than for the flight we see in modern birds.

Source: Zheng, X.-T., You, H.-L., Xu, X. & Dong, Z.-M. An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458, 333–336 (2009).
DOI: 10.1038/nature07856.
Hyperlink to original article:


  1. So there were actually non-avian dinosaurs that had feathers? I assume larger types like Tyrannosaurus and Stegosaurus lacked feathers, but I could be wrong. This is neat to known considering the only dinosaur that I knew of with feathers was Archaeopteryx.

  2. What kind of advantage would feathers be over scales? If it was display it would seem more likely the scales change color/design like reptiles today.

  3. The phylogenetic extent of feathers in dinosaurs can be surprising, and we will be talking about it in class. One point that is really significant about this article is its finding that an ornithischian dinosaur had feathers. All known feathered dinosaurs previously came only from the saurischia, to which birds, tyrannosaurids and velociraptors belong. If these feathers are truly homologous to saurischian feathers, then the origin of early feathers predates the split between the ornithischia and saurischia.

    And yes, there is good evidence that juvenile tyrannosaurids (a saurischian) had feathers.

  4. I knew there was something off about the lack of evidence for feathers in Ornithisichians. Finding further evidence of feathery bristles in them (other than Psittacosaurus) makes my day. ^_^