[Tapper]

As the title says.
Just a wild guess, based on the following:

1) Pearl said it was a 'she' Dragon. There are not many of those, and we know those, right?
(From bottom to top in the DT: Phaed, (possibly) Envy, Spite, Sheltatha Lore, Sukuhl, Menandore, Tiam).

2) she was confined in a warren, fixed in place by spikes, which of course restricts manoeuverability, and if you don't bleed to death, you can't be reborn (as Tiam has done on several occassions according to the sources, sorry, no quote here).
The same principle as Brys Bedict applied to Rhulad, btw.

3) The Otataral Dragon was crucified by other Dragons, according to Pearl and Lostara. Could it be that Tiam's Tiste offspring nailed her to a cross to prevent her from mating or sharing blood with humans, thus establishing a monopoly of Draconian form among the various ancestors of the Tiste and the Elder Gods?

4) Tiam can be reborn, at least after giving birth, so: why isn't she around if she isn't confined somewhere?

Of course, one weakness of my "theory" is the Soletaken Bonecaster, who was female as well, if I'm not mistaken.
I doubt she was around when the Children of Mother Dark and Father Light were drinking Tiam's blood or doing the wild thing with her.

Another gap is the lack of explanation for a connection between Tiam and Otataral as her aspected element.

So, any thoughts?