Page 78 - The Origin of Birds and Flight

In another possible simi-
larity with crocodiles, scientists found
evidence in the infant dinosaur of a specialized breath-
ing device called a hepatic piston. 3
In this way, Ruben and his team once again showed that bellow-type
4
lungs could not have evolved into the high-performance lungs in birds. An
article published in Science magazine, “Lung Fossils Suggest Dinos
Breathed in Cold Blood,” refers to his research:
Ruben and his graduate students sectioned crocodiles and other reptiles
and found that their lung structures resembled the images of several flat-
tened fossil dinosaurs from China. Ruben uses this lung evidence to
argue not only that dinosaurs were incapable of the high rates of gas
exchange needed for warm-bloodedness, but also that their bellows-like
lungs could not have evolved into the high-performance lungs of mod-
ern birds. Thus, he challenges two of the reigning hypotheses concern-
ing dinosaurs: that they were warm-blooded and that they gave rise to

Scientists studying the
internal organs of
Sinosauropteryx, a 120-
million-year-old small
carnivorous dinosaur,
revealed that theropods
resembled crocodiles
more closely than birds.

American crocodile

Proponents of the dino-bird thesis cannot offer any coherent
explanation of the “evolution” of birds’ highly
complex lungs, which differ from
those in all other vertebrates.
But still they close their
eyes to all the evidence
against their theory.