Tiny Prehistoric Birds and Pterosaurs

Just a quick note. 
This blog is all about putting taxa together that don’t usually — or never — get together. Here I’ll just present a few birds and pterosaurs at the small end of the scale.

Small prehistoric birds and pterosaurs.

Figure 1. Small prehistoric birds and pterosaurs. From left to right, Sinornis, Cathayornis, No. 6 and No. 12 from the Wellnhofer (1970) catalog of “pterodactyloids.”

Both tiny birds and tiny pterosaurs dispensed with their long stiff tail. In birds it became a pygostyle. In pterosaurs the long stiff tail became a reduced, string-like tail with bead-like verts. Note the similarities in the pectoral girdles. Both could stand with their toes beneath their shoulder glenoids. Both had retroverted pedal digits but of two distinct designs. The anterior ilium of both taxa supported large thigh muscles. A large deltopectoral crest supported large flight adductors anchored to the sternum.

Size-wise, the tiny birds were not considered juveniles, but the pterosaurs were. Phylogenetic analysis illustrates the uniqueness of the two small pterosaurs. They cannot be matched to any larger adults that are phylogenetically close. Rather they are parts of a phylogenetic sequence of other tiny pterosaurs descending from larger forms and leading toward larger forms.

With regard to the tiny pterosaurs, I sense prejudice here. Just like tiny birds, let’s give them full adult rights and add them to a few new analyses to test the large pterosaur tree topology.

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.

Wellnhofer P 1970. Die Pterodactyloidea (Pterosauria) der Oberjura-Plattenkalke Süddeutschlands. Abhandlungen der Bayerischen Akademie der Wissenschaften, N.F., Munich 141: 1-133.



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