I see nothing implausible about extracting DNA from blood cells found in a mosquito's gut. Although mammalian red blood cells and platelets both lack nuclei, bird blood cells have nuclear DNA one could theoretically recover.
|Mr. DNA comes from non-mammalian blood|
Unfortunately, the half-life of DNA is only about 521 years even under ideal conditions. The quantity of any substance with this half-life left over since the extinction of the dinosaurs during the KT extinction event is pretty easy to calculate.
(1/2)^(66 million / 521) = 4.81*10-38135
Though it's hard to make sense of a number this small.
I think we can all agree there were fewer base pairs of dinosaur DNA on the Earth 65 million years ago than there are atoms in the universe. Since there are only about 1080 atoms in the observable universe we can immediately conclude that the expected number of base pairs of dinosaur DNA remaining intact today is zero.
So the the fictional cloning technique in Jurassic Park can't work.
Looks like we're stuck with the dinosaurs we've got.