This video says about itself:
One of the most dramatic and mysterious events in the history of life, the so-called “Great Dying” of animals and plants some 250 million years ago, continues to fascinate and baffle scientists. Of the five or so mass extinctions recorded in Earth’s fossils, this one at the end of the Permian period and the start of the Triassic was the most catastrophic.
There Once Was a Shark That Ate an Amphibian That Ate a Fish …
By Charles Q. Choi, Special to LiveScience
posted: 27 November 2007 07:33 am ET
A fossilized shark that swallowed a crocodile-like amphibian that, in turn, had gobbled up a fish has now been unearthed.
This exceptional find marks the first time scientists have found direct evidence of such a complex, extinct food chain.
In the past, researchers had uncovered evidence of what past species ate based on the fossilized contents of their guts or droppings. For instance, fossilized dung, or “coprolites,” have revealed some dinosaurs ate grass.
“Prey, especially in the gut or intestines of fossil organisms, are very rarely preserved,” said paleobiologist Jurgen Kriwet at Humboldt University of Berlin in Germany. At most, only a single victim or perhaps several of the same species are preserved, he added.
By accident, Kriwet and his colleagues discovered the new shark fossil in a museum collection. These exceptionally preserved remains are roughly 290 million years old, pre-dating the emergence of the dinosaurs.
The freshwater shark, some 20 inches (50 centimeter) long, dates back to the late Permian period, when the Saar-Nahe Basin in southwest Germany was peppered with short-lived lakes. In the shark’s gut were two young amphibians known as temnospondyls, each roughly 8 inches to 10 inches (20 to 25 centimeters) large.
“The temnospondyl was crocodile-like,” Kriwet said. “The temnospondyls in the gut of the shark were larvae. Their adult equivalents grew very big up to one meter (three feet), maybe more, and they occupied the niche that is occupied today by crocodiles in lakes.”
“Crocodiles were not around in the Permian,” he added. “They evolved much later.” The disappearance of the temnospondyls appears linked with the rise of the crocodiles, Kriwet explained.
In turn, one of the amphibians possessed the remains of a digested bony fish that was about four inches (10 centimeters) long during life. Adults of this fish grew up to 20 inches (50 centimeters) or more.
The remarkable fossils shed welcome new light onto the ancient world. For instance, “no other extinct or modern, living shark is known to feed on amphibians,” Kriwet told LiveScience.
Future research could help reconstruct ancient food webs “and might shed light on how modern food webs in aquatic systems arose.”
The findings were detailed online Oct. 30 in the journal Proceedings of the Royal Society B.
See also here.
Amphibians and evolution: here.
Salamander-like development in a seymouriamorph revealed by palaeohistology: here.
The world’s only animal, past or present, with a complete 360-degree spiral of teeth was Helicoprion, which sliced into prey like a buzz saw. This shark-like fish, which lived 270 million years ago, is described in the latest issue of Biology Letters. It had one of the most unusual mouths and sets of teeth in the animal kingdom: here.
Prehistoric sharks escaped mass extinction 252 million years ago by ‘seeking refuge in the depths of the ocean’: here.
- Buzzsaw!: An ancient spiral-toothed shark (whyevolutionistrue.wordpress.com)
- Paleontologists Solve Mysteries of Permian Whorl-Toothed Shark (sci-news.com)
- Ancient Tapeworm Eggs Found in Fossilized Shark Poop (livescience.com)
- Chainsaw-Toothed Shark Fossil Uncovered (escapistmagazine.com)
- Toothy Spiral Jaw Gave Ancient Sea Predator an Edge (livescience.com)
- Ancient sea predator used toothy spiral jaw to get an edge (mnn.com)
- Finned Monster Chomped Heads Off Ancient Amphibians (livescience.com)
- Fossil of Ancient Amphibian Choking on Last Meal Up for Auction (livescience.com)
- How Cheeky: Fossil Fish Is Oldest Creature With a Face (livescience.com)