Taxonomy term

vertebrate

Permian-Triassic extinctions timed differently on land and at sea

Life on land and in the sea was nearly eradicated about 252 million years ago in the largest-known mass extinction. The cataclysm, known as the Permian-Triassic (P-T) mass extinction, was likely driven by extensive flood basalt volcanism in Siberia and is thought to have affected global biodiversity simultaneously. However, based on analyses of rocks deposited around the time of the P-T boundary in the Karoo Basin of South Africa, scientists suggest in a new study that the terrestrial turnover in vertebrates occurred earlier than the marine extinction. If true, a second trigger — other than Siberian volcanism — might need to have occurred to explain both events.

31 Jan 2016

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Early Triassic fossil showed live birth in action

An exceptional case of fossil preservation has provided the oldest view yet of the moment of live birth in a vertebrate. The fossil contains parts of four marine reptile individuals — a mother and her three young — from the ichthyopterygian genus, Chaohusaurus, and was unearthed in the Anhui Province of eastern China. While one of the young is still inside the mother and a second is already outside (and mostly obscured from view by other portions of the fossil), the third juvenile can be clearly seen emerging headfirst from the mother’s pelvis. Thought to be about 1 meter long when fully grown, Chaohusaurus lived about 248 million years ago in the Early Triassic and was an ancestor of later ichthyosaurs.

22 Jun 2014

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Down to Earth With: Adrian Hunt

Adrian Hunt grew up in England, but after earning his undergraduate degree in geology at the University of Manchester, he began looking for somewhere foreign to attend graduate school. At the time, Hunt says, he thought, “If it doesn’t work out, at least I’d see somewhere exotic.” He ended up in New Mexico, where his brother was working at the National Radio Astronomy Observatory’s Very Large Array in Socorro. It worked out and Hunt stayed to complete a master’s degree at the New Mexico Institute of Mining and Technology, followed by a doctorate at the University of New Mexico in Albuquerque.

18 Mar 2013

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Do impacts trigger extinctions? Impact theory still controversial

The revolution started with a bang in 1980. For some, this revolution became a religion, even an orthodoxy. The true believers became proselytes and began to see signs supporting their viewpoint everywhere. But each time the proselytes claimed to have found yet another example in support of their “religion,” naysayers and doubters emerged. Two sides formed, each loudly castigating and questioning their opponents.

This back-and-forth ideological debate describes both the historical and still-ongoing struggle over a purported cause of mass extinctions: the meteor impact theory.

23 Jun 2010

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Tetrapod tracks reset timing of four-legged evolution

About 18 million years earlier than they were thought to exist, tetrapods — vertebrates with four limbs instead of fins — walked in what is today Poland. A new study published in Nature describes tracks belonging to a tetrapod in a Polish tidal flat, dating to the Middle Devonian period, about 395 million years ago. The discovery may prompt scientists to completely reassess the environment, origins and timing of early tetrapods.

07 Jan 2010