Re: Paronychodon

[Michael Mortimer <mickey_mortimer111@msn.com>]

Phillip Bigelow wrote-

> To what taxon are these teeth now attributed?

Rauhut (2002) suggested some Paronychodon teeth were archaeopterygids-

"A new interpretation proposed here is that the cf. Paronychodon teeth from 
Un? a might represent bird teeth. Characters in favour of this 
interpretation are the constriction between crown and root (Currie, 1987) 
and the inwardly bent carinae as well as the labio-distal twist of the tooth 
tip; the latter two characters are also found in Archaeopteryx (Weigert, 
1995; compare Figure 2C with Weigert, 1995, fig. 7.1.). The fact that the 
teeth of the Upper Cretaceous toothed birds Hesperornis and Ichthyornis 
differ in not showing inturned carinae and a labio-distal twist of the tip 
of the crown (Marsh, 1880) might indicate that these characters are 
archaeopterygiform synapomorphies, thus making cf. Paronychodon a possible 
late survivor of the Archaeopterygiformes. That the archaeopterygiform 
lineage survived into the Late Cretaceous is demonstrated by Rahonavis from 
the Maastrichtian of Madagascar (Forster et al., 1998). However, teeth of 
Archaeopteryx differ from Paronychodon teeth in their sigmoidal shape 
(Weigert, 1995)."

There is actually a partial coelurosaur dentary containing teeth grooved 
like Paronychodon, described by Zinke and Rauhut (1994), but it differs from 
Paronychodon in some ways (serrated teeth, etc.).  Of course, the dentary is 
from the Late Jurassic, so its teeth are not expected to be identical to the 
Late Cretaceous Paronychodon holotype.  In any case, Zinke and Rauhut 
concluded it was most similar to troodontids, though lacked some troodontid 
synapomorphies.  Maybe it and other paronychodonts are related to the 
bird-like basal troodontids (Mei, Jinfengopteryx, the new Mongolian taxa, 
etc.)?

Mickey Mortimer