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

Re: Vegavis gen. nov. - new anseriform in today's Nature




On Thu, 20 Jan 2005, David Marjanovic wrote:

> > Birds should have been affected as badly as non-avian dinosaurs.
>
> Why do you think so?

Feduccia's response to the K duck is that it couldn't be a duck because
the extinctions were too devastating for ducks to survive!

Most birds have advantages on their side that most
> other dinosaurs lacked:
> - Small size. Means, large populations, low food requirements, easier to
> find shelter...

At the instant the asteroid hit there were sure many small juvenile
non-avian dinosaurs, surely with adaptation for hiding.  It's as if the
non-avian dinosaurs were freaks, without instincts for seeking cover etc.
Given the "lawn-mower" ecology, juvenile dino babies would have had
similar access to protection as birds.

> - Flight. Means the ability to cheaply cover vast distances in search of
> food, mates, nesting sites and whatnot. This in turn means that much fewer
> individuals per continent need to survive to continue the species.

So, now you're saying na dinosaurs survived in some locations but couldn't
find mates because they couldn't fly?  This _is_ becoming less extreme!

> - Ability to live off seeds (Galliformes, Palaeognathae).

...and who knows how many non-avian dinosaurs.

> - Ability to live off insects (Galliformes, Palaeognathae, who knows what
> else).

Ditto...check the diet of juvenile crocs.

> Evidence for Cretaceous members of Neoaves -- a huge clade! -- is still
> quite poor. Besides... the more species we find that are _not_ ancestral to
> extant species, the _more_ support there is for an instantaneous,
> all-encompassing catastrophe... and this, too, is going on now, partly by
> new finds (the toothed bird of Maastricht, *Limenavis*...), partly by
> revisions of known specimens (*Iaceornis*, probably *Polarornis* and
> *Neogaeornis*...).

OK...so now you need another mechanism, one that kills off the old birds
and spares the new.  This is sounding more and more like angels on
pinheads.