Giant flying arboreal mammal-killer in the Jehol (Early Cretaceous, China)

So… this one has been under the radar since 2004
And you’ll see why.

Like a prehistoric eagle,
this was the largest flying predator in the Jehol biota (Early Cretaceous, China). It had no feathers. And it has gone unrecognized as a giant flying predator since Wang and Zhou 2004 announced it in Nature for other reasons.

At this time the only evidence
for this taxon comes in the form of a giant embryo anurognathid pterosaur, IVPP V13758 (Fig. 1) the size of other adult anurognathids. As an adult it would have been 8x larger (if similar to other pterosaur and based on the pelvic opening). The skull retains traits of the related, but more basal Dimorphodon from the Early Jurassic of England, but the giant anurognathid was coeval and similar in size to another Jehol predator, the pre-tyrannosauroid, Tianyuraptor, and larger than a coeval four-winged, flight-feathered ornitholestid, Microraptor (Fig. 1). It was also larger than the modern bald eagle (Haliaeetus leucocephalus). All the early Cretaceous toothed birds, like Yanornis, and Hongshanornis, were smaller.

Figure 1. Adult scaled version of the IVPP anurognathid pterosaur, with a skull similar in size to those attributed to Dimorphdodon. Bergamodactylus and Preondactylus are ancestral to Dimorphodon. Other Jehol predators are shown in white.

Figure 1. Adult scaled version of the IVPP anurognathid pterosaur, with a skull similar in size to those attributed to Dimorphdodon. Bergamodactylus and Preondactylus are ancestral to Dimorphodon. Other Jehol predators are shown in white.

If early Cretaceous mammals thought they were safe up in the trees,
think again. This giant anurognathid kept their numbers in check by going after them in the trees. That’s a big guess, but if you’re looking for a predator capable of snatching mammals out of the trees, there are no other candidates in the Early Cretaceous of China. Just look at those teeth!

Most anurognathids were small
because they ate small insect prey. Ask yourself if something as large as the IVPP embryo as an adult would have been satisfied eating insects. No, it was going after larger prey.

Figure 1. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

Figure 2. Large anurognathids and their typical-sized sisters. Here the IVPP embryo enlarged to adult size is larger than D. weintraubi and both are much larger than more typical basal anurognathids, Mesadactylus and MCSNB 8950.

Unfortunately
Wang and Zhou 2004 (Fig. 3) didn’t know what sort of pterosaur their first embryo/egg was. Back then they thought pterosaur babies had a shorter rostrum that adults. Wrong. Back then they thought anurognathids were all small taxa. Wrong. Back then they didn’t spend much time tracing traits (Fig. 3) and reconstructions were largely guesswork. We fix all those problems here and at ReptileEvolution.com

The IVPP embryo pterosaur

Figure 3. Click to enlarge DGS tracing. The IVPP embryo pterosaur (far left) as originally traced, (near left) as originally reconstructed as a baby ornithocheirid, (near right) traced using the DGS method, (far right) adult reconstructed at 8x the embryo size.

We first looked at the IVPP embryo
here, several years ago and several times since.

Figure 4. The IVPP embryo anurognathid compared to other basal pterosaurs.

Figure 4. The IVPP embryo anurognathid enlarged to adult size and compared to other basal pterosaurs.

References
Wang X-L and Zhou Z 2004. Palaeontology: pterosaur embryo from the Early Cretaceous. Nature 429: 623.

http://reptileevolution.com/dimorphodon.htm
http://reptileevolution.com/ivpp-embryo.htm

https://pterosaurheresies.wordpress.com/2011/07/26/what-do-those-pterosaur-embryos-really-look-like/

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 )

Google photo

You are commenting using your Google 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 )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.