silurian period

Tagged by @urzum

Rules: Answer eight questions and tag eight people.

▪️Last movie I watched: Rogue One: A Star Wars Story (yeah it has been quite a while since a watched a movie hahaha)
▪️Last song I listened to: Comeback - Foo Fighters
▪️Last book I read: Fellowship of the Ring (still reading it)
▪️Last thing I ate: an egg sandwich
▪️Where would you want to time travel to?: I have always thought that it would be cool to go back to the Cambrian, Permian or the limit between the Ordovician and Silurian periods. Going back to the Proterozoic eon would be great too… Or 3 years ago too!.

▪️Fictional character I would hang out with for a day: Geralt of Rivia, Jaskier, Artyom, Thrall, Sylvanas Windrunner, Chen Stormstout, Rexxar, Tirion Fordring, Typhus, Mortarion and the list could go on and on…

▪️If I could be anywhere right now, where would I be: just want to be right here, in my house

▪️Current fandom obsession: Warcraft, Hitman (or Agent 47), The Witcher Saga, Warhammer 40K, Metal Gear

Tagging: @revenge-willcome, @camilalala, @pyretta-blazee, @l3go-r0jo, @asatreeinthemist, @deadeathh, @moominland, @iamtheonewho-knocks, @nargaroth, @adyrss, @countess-grishnackh

In this week’s Trilobite Tuesday, we present a brief history of the ebb and flow of trilobite evolution. These amazing arthropods existed for nearly 300 million years of earth history, during which time they produced over 25,000 different scientifically recognized species. But the fact is that after presenting a dizzying array of species during the Cambrian, Ordovician and Silurian periods, by thetime the trilobite line reached the Devonian some 400 million years ago, their species count had dwindled down to a precious few. And by the time the Mississippian began, their was ostensibly only one order of trilobites left—the Proetids. Here is an attractive example of a “double” Ameropiltonia lauradanae from the Mississippian-age shale of Missouri. These proetids were among the last survivors of the noble trilobite lineage.

Learn much more on the Museum’s trilobite website

FACT #94:

How long have sharks been around for?

Originally posted by liepsna

But there is no disagreement that scales found during the Silurian Period, aged 420 million years, are from sharks. Shark scales from this period have been found in Siberia and Mongolia. The oldest shark teeth are from the Devonian Period, about 400 million years old, found in Europe.

src

sauropolis-princeps  asked:

how bout some discourse on everyone's favorite devonian dunkster, dunkleosteus?

Ah, Dunkelosteus - truly the T. rex of the Devonian.  (Every geological period seemed to have its own T. rex - or at least that’s what cliche-loving paleo-writers like to claim.  What’s the T. rex of the Holocene, I wonder?  Probably… man.)

Dunkleosteus belonged to a taxonomic class of fish called the placoderms, characterized by the bony armor that covered their heads and upper bodies.  They were incredibly successful during the Silurian and Devonian periods, and were the first animals to display a number of now-commonplace characteristics, such as pelvic fins and teeth.  Ultimately, the entire group went extinct at the end of the Devonian period, and the ecological niches that were left vacant by their extinction were quickly filled by either modern “bony fish” or primitive sharks.

At the times when it lived (380 to 360 million years ago), Dunkleosteus was one of the largest animals on Earth, growing up to 33 feet in length.  Instead of teeth, it possessed a beak-like set of sharp-edged jaw plates, capable of producing enough force to effortlessly crunch through the tough outer shells of other placoderms.  

Dunkleosteus is believed to have puked up the hard parts of its prey rather than digest them, as indicated by the high numbers of fossilized vomit piles found in Devonian rocks.

Dunkleosteus has been growing in pop-culture popularity recently, likely due to its predatory badassery as well as the iconic image of its skull plates.  Although I’m sure ol’ Dunky is rolling in its grave now that the puny sharks it once preyed on are now dominating the seas where it once did, its starring role in Chased By Sea Monsters hopefully provides a bit of consolation.

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A fossil of Eurypterus remipes, a “sea scorpion” that lived during the Silurian Period (432-418 million years ago)  While they averaged about 6 inches long, one large individual has been discovered that was 4.3 feet in length.  The largest known species of Eurypterid could reach a monstrous size of 8 feet long.

All Eurypterus possessed paddles which they could use to swim but most likely walked as a primary means of locomotion.  They were most likely, exclusively marine animals with their fossils being found in shallow, intertidal environments.  Eurypterus is the state fossil of New York.

For more fossil photos, news and links be sure to follow the Fossil Porn Tumblr Blog.

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The Blue Ridge Mountains

are a physiographic province of the larger Appalachian Mountains range. The mountain range starts at its southernmost portion in Georgia, then ends northward in Pennsylvania.
The Blue Ridge contains the highest mountains in eastern North America south of Baffin Island. About 125 peaks exceed 5,000 feet (1,500 m) in elevation. The highest peak in the Blue Ridge (and in the entire Appalachian chain) is Mt. Mitchell in North Carolina at 6,684 feet (2,037 m). Most of the rocks that form the Blue Ridge Mountains are ancient granitic charnockites, metamorphosed volcanic formations, and sedimentary limestones. The Blue Ridge Mountains began forming during the Silurian Period over 400 million years ago.
The English who settled colonial Virginia in the early 17th century recorded that the native Powhatan name for the Blue Ridge was Quirank. At the foot of the Blue Ridge, various tribes including the Siouan Manahoacs, the Iroquois, and the Shawnee hunted and fished.