15.4.06

TECTONIC SHIFTS. The fossilized Darwin fish, Tiktaalik roseae, that paleontologists recently unearthed on Ellesmere Island, is a creature from the Devonian period. This article described the creature as native to warmer climes.
The fishapod was among the pioneering organisms to take advantage of an ecological frontier--the marshy floodplains of large rivers--that opened between 410 million and 356 million years ago during the Devonian period, known as the Age of Fishes. Early in the Devonian, the continents were mostly masses of bare rock with just a fringe of plants "no taller than your ankle," as Daeschler puts it, growing along the wet margins of rivers and streams. By the late Devonian, however, thick vegetation had taken hold in marshes, fens and floodplains, and mosses, ferns and trees had coalesced into the world's first forests.
That got me thinking ... there's continental drift (great animation here), there have also been ice ages, what does a tropical fossil in Canada tell me about the potential extremes of naturally-occurring global warming? The Devonian site tells me: insufficient data.
During the Devonian, there were three major continental masses: North America and Europe sat together near the equator, much of their current land underneath seas. To the north lay a portion of modern Siberia. A composite continent of South America, Africa, Antarctica, India, and Australia dominated the southern hemisphere.
So this fishapod lived and died in tropical conditions and its remains ultimately drifted with the North American plate to more wintry climes. But this site mentions mass extinctions toward the end of the era, with meteorite impacts or glaciation the likely suspects.

Do you find that term "fishapod" as charming as I do? Consider some of the Steamozoic era relics in my basement, including several Decapods and the one, the only Quartadecapod.

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