280 million-year-old fossil reveals origins of chimaeroid fishes

Science Life

High-definition CT scans of the fossilized skull of a 280 million-year-old fish reveal the origin of chimaeras, a group of cartilaginous fish related to sharks. Analysis of the brain case of Dwykaselachus oosthuizeni, a shark-like fossil from South Africa, shows telltale structures of the brain, major cranial nerves, nostrils and inner ear belonging to modern-day chimaeras.

This discovery, published early online in Nature on Jan. 4, allows scientists to firmly anchor chimaeroids—the last major surviving vertebrate group to be properly situated on the tree of life—in evolutionary history, and sheds light on the early development of these fish as they diverged from their deep, shared ancestry with sharks.

“Chimaeroids belong somewhere close to the sharks and rays, but there’s always been uncertainty when you search deeper in time for their evolutionary branching point,” said Michael Coates, PhD, professor of organismal biology and anatomy at the University of…

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Arctic Air Temperatures are Set to Hit 35 to 55 F Above Average by Thursday — Out of Season Sea Ice Melt Possible, Again

robertscribbler

“It looks like a triple whammy – a warm ocean, a warm atmosphere, and a wind pattern all working against the ice in the Arctic.”NSIDC director Mark Serreze.

“Unfortunately, Arctic sea ice extent growth has once again slowed this week…”Zack Labe

“Huge surface air temperature anomalies over the Arctic this working week… over 25C warmer than average in parts.” — James Warner

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This year, it’s a challenge to find a time when the Arctic Ocean has ever represented anything resembling normalcy. Record low sea ice extent values have occurred for more than 50 percent of days measured. And well above average temperatures have invaded the Arctic during winter, spring, and fall. With another huge wave of ridiculous warmth building up over eastern Siberia this week, the hits just keep on coming.

Major Warming Over Siberia, Chukchi and East Siberian Seas 

The present big…

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