On Wednesday, April 20, 2016 at 3:13:01 AM UTC+7, Lynn McGuire wrote:
> "Dinosaurs weren’t driven to extinction by that meteorite after all"
>
http://arstechnica.com/science/2016/04/dinosaurs-werent-wiped-out-by-that-meteorite-after-all/
>
> "New evidence shows that dinosaurs were dying out 24 million years before bolide impact."
>
> Well, there goes a lot of perfectly good SF stories.
>
> I wonder how valid their count is?
>
> Lynn
Well, here's what I wrote on the topic of dinosaur extinction nearly 20 years ago in the group sci.biology.evolution. My contention is that the newly evolved eutherian mammals played a role in the extinction of the dinosaurs. I used the word *placental* not *eutherian* back in 1996 but what I said back then still applies.
sci.bio.evolution ›
Mammals as a cause of Dinosaur Extinction
10 posts by 7 authors
AC2
8/19/96
Why does Stephen Jay Gould completely ignore the possibility that mammals
may have been a factor in the extinction of the dinosaurs some 65 mya.
Instead, he says that mammals and dinosaurs co-existed throughout the
Jurassic and Cretaceous and that this demonstrates that mammals did not
consume the Dinosaur young leading to the demise of that group. I remember
this theory from a 1950's textbook.
Giant reptiles (turtles) have "ruled" the Galapagos islands for a long
time. It is my understanding that recently imported dogs and cats have
caused a decline in the turtle population due to their predation of turtle
hatchlings. The same predation has also reduced the population of the other
Galapagos "rulers", the Iguanas. Why is it not a feasible possibility that
newly evolved (Late Cretaceous that is) placental mammals damaged the
dinosaur population by eating their young. The adult Dinosaurs (just like
adult Galapagos turtles) would be invulnerable to mammal attack but their
young would not be so lucky. Question--- When did definable placental
mammals evolve? Was it not in the Late Cretaceous, at about the same time
that the number of Dinosaur species declined?
Newly imported mammal species also exterminated the "rulers" of Mauritius,
the Dodos, some 3 centuries ago and seem to be doing the same today to the
ruling Tuataras, Kiwis and Parrots of New Zealand. In addition, it is my
understanding that the largest predator of the Paleocene (post Dinosaur)
was the 2 metre tall Diatryma which was eventually superseded by mammalian
Creodonts and true carnivores. Is my understanding correct? If Diatryma was
destroyed by placental mammal competition why not Troodonts or
Velociraptors.
I do not claim that mammals were the sole or even a major cause of Dinosaur
extinction. I believe that it was a factor and should not be summarily
dismissed.