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[caltrek]

Russian Saber-Tooth Fossils Illuminate Early Evolution of Mammal Lineage

 

https://www.courthou...mammal-lineage/

 

Introduction:

 

(Courthouse News) – Researchers have discovered the fossils of two new species of ancient saber-toothed predators that will help illuminate a key period in the early evolution of mammals.

 

The lineage of modern mammals can be traced back to a group of animals called therapsids, a diverse group of “protomammals” that dominated terrestrial ecosystems during the Permian period approximately 299 to 252 million years ago — millions of years before dinosaurs first roamed the planet.

 

A pair of studies published Friday in the journal PeerJ describe two previously unknown species of predatory protomammals.

 

Discovered near the town of Kotelnich along the Vyatka River in Russia, the fossils add to the Vyatka Paleontological Museum’s collection of well-preserved Permian fossils.

 

As the majority of Permian fossils have been discovered in South Africa’s Karoo Basin, the newly described remains help balance out the outsized role the African nation’s record serves in informing researchers’ understanding of protomammal evolution.

The therocephalian Gorynychus masyutinae, top predator of the Kotelnich fossil assemblage, hunting a tree-dwelling herbivore (Suminia getmanovi).

(Matt Celeskey)

[caltrek]

In South Africa, Digging for Clues to an Ancient Extinction — and the Planet’s Future

 

https://undark.org/a...e-south-africa/

 

Introduction:

 

(Undark) IN JANUARY, I stood in a ditch in the middle of nowhere in South Africa, and the summer sun beat down as I stared at a heap of grape soda-colored rocks. Bob Gastaldo, the paleontologist whose research team I had been following through the Karoo, had his back turned and was busy striking these quarter-billion year-old rocks — residues of a mass extinction that caused about 70 percent of all land life and 96 percent of all marine life to vanish permanently — with his hammer.

 

The extinction has a few names. One of them is the Permian-Triassic (PT) mass extinction, for the two geologic periods it separates; another is the “Great Dying,” for all the life-ending change it caused. It is the biggest extinction of the so-called “Big Five” mass extinctions that punctuate the history of life on our planet, and, according to many researchers, one of the best places to see the PT land extinction as it exists in Earth’s many-layered rock record is in the Karoo, a vast, semidesert region of south-central South Africa.

 

Where I stood in that ditch, the extinction horizon — that is, the point where the rock layers go from Permian to Triassic in age — is supposed to be somewhere amid the rocks that were in front of me. If some of these rocks were gravestones, you would see names like Diictodon and Daptocephalus — names of land animals that missed the train to the Triassic. Near the ditch, Gastaldo had tripped over the fossil skull of what was probably a Lystrosaurus.

 

Other paleontologists, including Roger Smith of the Iziko South African Museum in Cape Town, believe the extinction of land animals suggested by these rocks coincided with a massive die-off of marine life. “It happened on land and it happened in the sea and it happened at the same time,” Smith told me. Then, as life reset itself, new species appear above the boundary.

 

Sandra Kamo, a geochronologist from the University of Toronto, hopes to determine the absolute ages of these rocks, which would make it clear when the land extinction happened.

Visuals: Lucas Joel