re: Parapsicephalus post-crania

[Unwin <h0662eka@rz.hu-berlin.de>]

Re: Parapsicephalus post-crania

The holotype and only known specimen of 'Parapsicephalus' purdoni, an 
incomplete but well preserved skull, shows, for example, an antorbital 
fenestra that is completely divided from the narial opening by a 
maxilla-nasal bar - a plesiomorphic condition within Pterosauria that 
does not support membership of 'P'. purdoni within Pterodactyloidea. 
Indeed, the skull of 'P'. purdoni shows remarkable similarity to skulls 
of the rhamphorhynchine Dorygnathus and I would even go so far as to 
suggest that 'Parapsicephalus' is a junior synonym of Dorygnathus. In any 
case, 'P'. purdoni has, so far, been universally accepted as a 
'rhamphorhynchoid', or to be more cladistically correct, a member of one 
of the non-pterodactyloid clades of pterosaur. 

By contrast, Wellnhofer's Exemplar 9 of Pterodactylus kochi exhibits all 
six of the principal pterodactyloid synapomorphies listed by Unwin (in 
press) and many others that were not discussed in detail because of space 
constraints. Moreover, the morphology of Exemplar 9 compares very closely 
with that of other individuals of Pterodactylus kochi and this individual 
also fits neatly into growth curves plotted for this species, 
irrespective of which comparison is being made. 

'Parasicephalus' purdoni and Exemplar 9 of Pterodactylus kochi belong to 
completely different clades and are clearly unrelated. There is no point 
in comparing the two, unless this is done within a wider cladistic 
analysis, so please count me out of the round table. 


References:

Unwin, D. M. In press. On the phylogeny and evolutionary history of 
pterosaurs. In: Buffetaut, E. (ed.), Evolution and Palaeobiology of 
Pterosaurs. Geological Society, London. 





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David M. Unwin PhD

Institut fur Palaontologie, MUSEUM FUR NATURKUNDE 
Zentralinstitut der Humboldt-Universitat zu Berlin
Invalidenstrasse 43, D-10115 Berlin, GERMANY

Email: david.unwin@rz.hu-berlin.de

Telephone numbers:
0049 30 2093 8577 (office)
0049 30 2093 8862 (department secretary)
0049 30 2093 8868 (fax)
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