Re: Proto-penguins lived with dinosaurs

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

> Here's the actual sentence.
>
> "Dna tests on the Waimanu penguin fossils, found near the Waipara
> River, have determined they are between 60 million and 62 million years 
> old "

AARGH!

I managed to overlook this -- but look at what it says later in the article:

> >
An Otago University geologist, Associate Professor Ewan
Fordyce, said modern theory was that most modern bird
groups evolved after the dinosaurs died out.

"By using the dates from the fossil Waimanu penguins as a
calibration point, we can then predict how far back in
time the other groups of living birds originated. If early
penguins lived in southern seas not long after the
extinction of dinosaurs, then other bird groups more
distantly related to penguins must have been established
even earlier."
<<

The good professor either did not explain what "using as a calibration 
point" means, or it got shortened away by the newspaper. So, one way or 
another, we are dealing with a journalist who has not done his &%§&§§$ 
_*JOB*_ of understanding what he's writing about.

Here goes: You take a molecular phylogeny of extant birds. (You can add a 
bit of moa DNA.) Then you send it through a round of molecular divergence 
dating. This will only give you relative dates. To get absolute dates, you 
must have at least one calibration point (the more, the better). Fordyce and 
friends took the 60 to 62 Ma of *Waimanu manneringi* (determined by 
traditional geological methods -- it's in a Danian layer) as the date of the 
divergence between Sphenisciformes and... whatever their molecular tree 
gives as the closest living relative.

Modern methods of molecular dating ( = less than 5 years old) do not require 
constant rates of evolution.

> I figured that they must have found usable DNA;

No.

> after all, there is DNA from dinosaur eggs,

Er... no.

> and DNA from ancient flies in amber.

That turned out to be a contamination long ago.