Pterosaurs to Birds: February 2019

Sunday, February 17, 2019

Convergence

It is sometimes said that coelurosaur dinosaurs and the ancestors of pterosaurs convergently evolved characteristics related to flying.
It is said that pterosaur characteristics related to flying were analogous (convergent) to that of birds, rather than homologous (ancestral).

Here is an example:
https://en.wikipedia.org/wiki/Pterosaur

A 2009 study showed that pterosaurs had a lung-air sac system and a precisely controlled skeletal breathing pump, which supports a flow-through pulmonary ventilation model in pterosaurs, analogous to that of birds.

But the parsimonious conclusion is that basal Paraves evolved FROM pterosaurs.

Here is a summary of the basic ideas of this site:

Birds developed in a lineage from short bony tailed pterosaurs to short bony tailed scansoriopterygids that developed into basal pygostylia that developed into modern birds. A side lineage earlier developed from the long tailed pterosaurs to long bony tailed scansoriopterygids. That lineage went extinct. The category called coelurosaur dinosaurs includes only actual dinosaurs (eg. tyrannosaurs). It does not include birds. The fossil record supports the pterosaur-to-bird theory. The fossil record does not support the dinosaur-to-bird theory.

Pterosaurs to Birds

Sunday, February 17, 2019

Convergence

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