Confuciusornis skull reconstructed with DGS

Confuciusornis sanctus 
(Fig. 1) is an early Cretaceous ornithurine bird known from hundreds of specimens (Chiappe et al. 1999) often preserved with full plumage. The skull is of the typical archosauromorph diapsid plan. The premaxilla is very long and toothless, like that of modern birds. The premaxilla extends to the frontal, separates the nasals and greatly reduces the maxilla. This was a bird with large manual claws, a substantial breastbone and a pygostyle instead of a long bony tail.

The problem is 
the skull of Confuciusornis has not been accurately traced (examples in black on Fig. 1). These prior examples do not attempt to capture the detail clearly available from the photographic data. Here DGS (digital graphic segregation) more accurately traces the elements then assembles them back to their in vivo positions.

Figure 1. GIF animation showing DGS tracing and reconstruction (in color) versus prior efforts in black.

Figure 1. GIF animation showing DGS tracing and reconstruction (in color) versus prior efforts in black. Here crushed elements are more accurately traced with colorized elements. These greatly facilitate the reconstruction below.

The resulting skull
greatly resembles that of Struthio and other basal birds and demonstrates the loss of teeth early in the evolution of ornithomorph birds.

Phylogeny
Chiappe et al. 1999 considered Confuciusornis the sister group of a clade composed of the Enantiornithomorpha and the Ornithomorpha. In the large reptile tree (now 592 taxa) it nests one node up, at the base of the Ornithomorpha.

Figure 3. Fossil of Confuciousornis. Note the large manual claws.

Figure 3. Fossil of Confuciousornis. Note the large manual claws.

This is but one more example
of a method that should be used universally for interpreting and reconstructing crushed fossils, DGS. This is also one more example that contradicts the tradition that one has to see the fossil firsthand in order to accurately assess its character traits. Several other examples have been posted previously. Keyword: DGS.

Figure 3. Confuciusornis pedal digit 5. When you look closely, you sometimes find things that are otherwise overlooked.

Figure 3. Confuciusornis pedal digit 5 (3 phalanges)  and metatarsal 5. Short black lines are at the joints. When you look closely, you sometimes find things that are otherwise overlooked.

References
Chiappe LM, Ji S-A, Ji Q, and Norell M 1999. Anatomy and systematics of the Confuciusornithidae (Theropoda: Aves) from the Late Mesozoic of Northeastern China. Bulletin of the American Museum of Natural History 242: 1-89.

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s