[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Hesperornis sp. nov.



Daniel Bensen wrote:
        
> The authors go on to say that there were likely two populations of
> Hespornorthithans by the late K, one northern, and one southern.  The
> southern ones had started their migration southward and so were more
> primitive, and existed in more genera (Hesperornis, Parahesperornis,
> Baptornis), while the northern fauna (which also extended into
> Asia---Asiahesperornis) 

What about _Enaliornis_? - do Martin and Lim exclude this bird from the
Hesperornithiformes (as mooted by some other authors)?

> "It is likely that ornithurines owe much of their success to an early
> colonization of water marginal habitats (martin, 1983, 1987).  

This has nothing to do with preservational bias?

> All the early neorniths _are_ shorebirds, after all (except maybe for 
> that parakeet).  

Ditto above.  I guess you're referring to those bits and pieces from New
Jersey (graculavids etc).  However, there is a big distinction between the
earliest *known* neornithines (as discovered in the fossil record) and the
most basal neornithines (as inferred from phylogenetic studies).  BTW, on
that last point, the base of the Neornithes (Palaeognathae, Galloanserae)
appears to include a disproportionate number of birds that fly poorly (e.g.
tinamous, screamers) or not at all (e.g. ratites, dromornithids).  I think
it's a stretch to say that the first Neornithes were (a) good fliers and (b)
water-loving.

Thanks for the info, Dan!

Cheers

Tim