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Tinirau, new Devonian marine stem-tetrapod

From: Ben Creisler

OK--not a dinosaur and not Mesozoic. However, the origin of tetrapods
is a major issue.


Swartz, B, (2012)
A Marine Stem-Tetrapod from the Devonian of Western North America.
PLoS ONE 7(3): e33683.

The origin of terrestrial vertebrates represents one of the major
evolutionary and ecological transformations in the history of life,
and the established timing and environment of this transition has
recently come under scrutiny. The discovery and description of a
well-preserved fossil sarcopterygian (fleshy-limbed vertebrate) from
the Middle Devonian of Nevada helps to refine and question aspects of
the temporal and anatomical framework that underpins the tetrapod
condition. This new taxon, Tinirau clackae, demonstrates that
substantial parallelism pervaded the early history of stem-tetrapods,
raises additional questions about when digited sarcopterygians first
evolved, and further documents that incipient stages of the
terrestrial appendicular condition began when sarcopterygians still
retained their median fins and occupied aquatic habitats.