Re: Sweet cynodont Thursday

[David Marjanovic <david.marjanovic@gmx.at>]

Ah, I knew I had seen that e-mail onlist...

> You know the oldest cynodonts are things like /Procynosuchus/ and 
> /Dvinia/?
> A couple of families bursting onto the stages of South Africa and Russia 
> at
> about the same time?  [...] This beat's been belted
> out by a more basal cynodont from the /Tropidostoma/ Assemblage Zone, and
> it's several million years earlier than the first record of 
> procynosuchids.

Except that Botha et al. don't mention why they put *Dvinia* deep into the 
Late Permian. According to the Geological Time Scale 2004, there is no Late 
Permian in Russia; *Dvinia* must come from the Capitanian, the last of the 
three stages of the Middle Permian. Now the question becomes how old the 
*Tropidostoma* zone of South Africa is. If it is as young as Botha et al. 
claim (the paper they cite for their correlation chart contains several 
mutually contradicting charts, but not that one, and isn't concerned with 
correlation across continents in the first place), *Charassognathus* is 
considerably younger than *Dvinia*. It goes without saying that at least one 
other correlation chart has been published recently. Let's just be glad 
there are no dinosaurs in the Permian. B-)