As we discussed several times earlier, the reconstruction of the skull of Anurognathus has been disfigured by Bennett (2007). He mistook a maxilla for a giant sclerotic ring preserved on edge. So his reconstruction (Fig. 1, left) with its giant eyeball and tiny antorbital fenestra, is distinctly different from all other anurognathid pterosaurs. Just yesterday we looked at the longer neck in the Anurognathus holotype, partially hidden by matrix.
Bennett considered his new specimen to be conspecific with the holotype. So, in his mind the two specimens were virtually identical.
Let’s test that idea.
Here (Fig. 2) I thought it would be helpful to take a closer look at the holotype of Anurognathus to see if that big opening also contained an orbit and was bordered by the correct bones, or not. Here’s how Bennett (2007) interpreted it (note the bone labels):
Where is the giant sclerotic ring?
In the Bennett (2007) interpretation of Anurognathus (Fig. 1 left), he identified a giant sclerotic ring in the anterior half of the skull. The holotype of Anurognathus (Fig. 2) preserves that portion, but there’s no ring here. Where is it? (It’s not there.)
Here’s an attempt to rectify those mistakes going back to the holotype:
The new study of the skull of Anurognathus identifies most of the bones of the skull and not too far from their in vivo positions and in line with the morphologies of other anurognathid skulls (Fig. 4). The Bennett (2007) skull is clearly the odd man out, the little monster. The sclerotic ring is behind the lacrimal (Figs. 3,4), above the jugal and below the postfrontal, as it should be.
This reconstruction of the Anurognathus holotype skull supersedes all other of my prior attempts, which are now in my waste bin. This is a difficult subject and mistakes in interpretation can be made by anyone, including yours truly. I invite comments and constructive criticisms if you see where an improvement can be made. Let’s get this right together!
Reconstructions of the entire Anurognathus can be seen here.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Bennett SC 2007. A second specimen of the pterosaur Anurognathus ammoni. Paläontologische Zeitschrift 81(4):376-398.
Bennett SC 2008. Morphological evolution of the wing of pterosaurs: myology and function. Zitteliana B28: 127-141.
Döderlain L 1923. Anurognathus ammoni, ein neuer Flugsaurier. Sitzungsberichte der Königlich Bayerischen Akademie der Wissenschaten, zu München, Mathematischen-physikalischen Klasse: 117-164.
Elgin RA, Hone DWE and Frey E 2011. The extent of the pterosaur flight membrane. Acta Palaeontologica Polonica doi: 10.4202/app.2009.0145 online pdf
Peters D 2001. A New Model for the Evolution of the Pterosaur Wing – with a twist. Historical Biology 15:277–301.