Re: Dinosaurs Had Sex As Youths, Study Says

["Richard W. Travsky" <rtravsky@uwyo.edu>]

On Wed, 25 Jul 2007, Dann Pigdon wrote:
> Richard W. Travsky writes: 
> > http://news.nationalgeographic.com/news/2007/07/070720-dino-sex.html
> > July 20, 2007
>
> The study assumes that the animals incubating the eggs were their parents - 
> which may not necessarily be the case. 
> Magpie geese here in Australia raise their goslings in threes instead of in 
> pairs; the parents of the eggs, and one of their offspring from the previous 
> year. I don't know whether big sister or brother also helps incubate the 
> eggs, but they certainly help to care for the hatchlings. Since magpie geese 
> share their swamps with crocodiles, it seems that having three pairs of eyes 
> looking out for trouble is better than two.

> From the article

 "Beyond the question of a reasonable doubt, these are the parents of
 those eggs," Curry Rogers said.

 The researchers examined thin cross-sections of bone from these
 dinosaur parents to determine whether they were fully grown.

 Similar to growth rings on a tree, fast-growing bones have lots of
 blood vessels. They also have a line marking where growth paused,
 then another pulse of growth, then another line, Curry Rogers
 explained. The outer layer of fully grown bones is a stack of
 lines.

 Two of the brooding dinosaurs examined in this study lacked the
 stacked lines, indicating the dinosaur parents mated before they
 reached full maturity.

It looks like they started from the incubatng evidence and use
the lack of stacked lines as justification for the conclusion,
however I don't know that the lack thereof means they mated...