by Katie Bowell, Curator of Cultural Interpretation
Earlier this month we posted about Anchiornis huxleyi, a four-winged, chicken sized dinosaur that’s the oldest bird-like dinosaur found to date, and now there’s yet another feathered fossil making headlines.
Meet Darwinopterus modularis, a pterosaur hailing from the Middle Jurassic (over 160 millions years ago) with a long tail, long snout with spiky teeth, and a single nasal opening. While any new dinosaur discovery is cool, Darwinopterus is especially interesting because characteristics of the fossil support a somewhat controversial theory of evolution known as mosaic evolution.
The theory of mosaic evolution states that major evolutionary changes tend to occur in stages, and not all together. In this theory, different pieces of anatomy can become disassociated from one another and evolve at separate rates (so a dental system and a locomotor system don’t have to evolve at the same rate). In the case of Darwinopterus, the fossil shares characteristics with the two major pterosaur groups that existed in the Jurassic. Early pterosaurs had long tails, short necks, and a separate nasal opening in their skulls. Later pterosaurs had short tails, long necks, and a nasal opening that was combined with another skull opening. Because some characteristics are so different between early and later pterosaurs, scientists believed there were intermediate forms between the two major groups. Enter Darwinopterus, with the body of an early pterosaur but the head of a later pterosaur. This representation of a “new” head on an “old” body supports the theory that anatomical “areas” can evolve at different rates.
Researchers don’t know yet if Darwinopterus was an ancestor of later pterosaurs; rather the new species is a “transitional form” that helps us understand how an organism group evolved.
For more information on Darwinopterus, visit Tetrapod Zoology.