Re: New Mesozoic mammal

[Amtoine Grant <ajgrant@eastlink.ca>]

On Wednesday, January 12, 2005, at 03:44  PM, Christopher Taylor wrote:
> "Mesozoic mammals are commonly portrayed as shrew- or rat-sized 
> animals that
> were mainly insectivorous, probably nocturnal and lived in the shadow 
> of
> dinosaurs. The largest known Mesozoic mammal represented by 
> substantially
> complete remains is Repenomamus robustus, a triconodont mammal from the
> Lower Cretaceous of Liaoning, China. An adult individual of R. 
> robustus was
> the size of a Virginia opossum. Here we report a new species of the 
> genus,
> represented by a skeleton with most of the skull and postcranium 
> preserved
> in articulation. The new species is 50% larger than R. robustus in 
> skull
> length. In addition, stomach contents associated with a skeleton of R.
> robustus reveal remains of a juvenile Psittacosaurus, a ceratopsian
> dinosaur. Our discoveries constitute the first direct evidence that 
> some
> triconodont mammals were carnivorous and fed on small vertebrates, 
> including
> young dinosaurs,

My question is, what diet was supposed for Repenomamus before discovery 
of one with stomach contents intact? And are there differences in 
dentition between the 2 species?

> and also show that Mesozoic mammals had a much greater
> range of body sizes than previously known. We suggest that Mesozoic 
> mammals
> occupied diverse niches and that some large mammals probably competed 
> with
> dinosaurs for food and territory."

Doesn't strike me as surprising - I recall a wildlife program showing 
ants kill baby crocodiles.