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/
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.
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.
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/
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.
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/
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