New pterosaur hatchling video from Dr. Witton misinforms

A new video
from Dr. M. Witton looks at the possibility of gliding in hatchling pterosaurs. Unfortunately it is full of misinformation.

Distinct from what Dr. Witton is telling us,
pterosaur hatchling and juvenile proportions are not much different than their 8x larger adult forms. See link below and this growth series image: https://pterosaurheresies.wordpress.com/2015/12/15/pterodaustro-isometric-growth-series/

From the hatchling Pterodaustro image,
Dr. Witton has omitted the skull and neck, but it is present in the egg (it has to be!) and is nearly identical to that of the adult. We looked at a second embryo earlier here (Fig. 2), and for the first embryo see:  http://reptileevolution.com/pterodaustro-embryo.htm for details.
Figure 3. Rough reconstruction using color tracings. Note the elongate jaws and small eye, documenting isometric growth in this pterosaur, as in all others where this can be seen.

Figure 2. Rough reconstruction using color tracings. Note the elongate jaws and small eye, documenting isometric growth in this pterosaur, as in all others where this can be seen.

Relatively large hatchlings
were able to take flight shortly after hatching. True. The eggs were carried within the mother until ready to hatch, as in many lepidosaurs. The eggshell membrane is also lepidosaurian.
In direct contrast,
the fly-sized hatchllngs of tiny pterosaurs had to grow to a size at which they could leave their damp leaf litter environs, or suffer from desiccation based on their surface-to-volume ratio, as in the tiniest living lizards.  See: https://pterosaurheresies.wordpress.com/2011/08/11/the-tiniest-pterosaur-no-6/
Figure 4. Two of the smallest pterosaurs that both have a large sternal complex. BMNH42736 and B St 1967 I 276.

Figure 3. Two of the smallest pterosaurs that both have a large sternal complex. BMNH42736 and B St 1967 I 276.

Gliding is not an option
for baby pterosaurs hatching on the ground. Pterosaurs and their ancestors were flapping before they could fly. Gliding is an ability acquired later in large derived taxa, the same as in birds.
FIgure 8. Dimorphodon take off (with the new small tail).

FIgure 4. Dimorphodon take off (with the new small tail).

The quadrupedal launch
shown in several illustrations is not only bogus, but dangerous and inefficient for the pterosaur. Much better to use the giant flapping wing for thrust from the first moment of take-off. For details: https://pterosaurheresies.wordpress.com/2011/07/20/seven-problems-with-the-pterosaur-wing-launch-hypothesis/
Figure 8. A larger view of Nemicolopterus. Pedal digit 5 is relatively reduced here.

Figure 5. Nemicolopterus. This tiny taxon is close to Sinopterus, but closer to Shenzhoupterous. 

Dr. Witton discusses a Sinopterus dongi hatchling.
He is considering tiny adult Nemicolopterus (Fig. 5) a hatchling. The Nemicolopterus specimen has traits distinct from Sinopterus and nests separately in a cladogram closer to Shenzhoupterus, whereas all other adult/hatchling pairs nest together in a pterosaur cladogram. See: http://reptileevolution.com/nemicolopterus.htm
Figure 1. The new small Pteranodon wing, FHSM 17956, compared to Ptweety and the adult NMC41-358 specimen.

Figure 6. The new small Pteranodon wing, FHSM 17956, compared to Ptweety and the adult NMC41-358 specimen.

We know of not one, but two Pteranodon juveniles.
For details: http://reptileevolution.com/pteranodon-juvenile.htm
For all future and present paleontologists reading this blog.
It is vitally important that you back up your hypotheses with evidence. Don’t cherry-pick or cherry-delete data to fit your notions or fool an audience.

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.