FLASH: Dinosaurs and Global Warming!!!

Global warming killed the dinosaurs...

Mystery of Prehistoric Marine Reptile's Extinction Explained
March 08, 2016 WASHINGTON — One of the enduring mysteries of paleontology, the demise of a highly successful group of dolphin-like marine reptiles called ichthyosaurs that flourished in Earth's seas for more than 150 million years, may finally have been solved. Scientists on Tuesday attributed the creatures' extinction 94 million years ago to the combination of global warming and their own failure to evolve swiftly enough.
The research, the most comprehensive analysis to date of their disappearance, undercut previous notions that ichthyosaurs had been in decline for tens of millions of years and were no match for competition from other predators, such as the fearsome oceangoing lizards called mosasaurs that were just arriving on the scene. The study showed that large mosasaurs in fact appeared only after ichthyosaurs went extinct. "We found ichthyosaurs were very diversified during the last part of their reign," said paleontologist Valentin Fischer of Belgium's University of Liege, noting that several species with various body shapes and ecological niches existed although ichthyosaur evolution had become relatively stagnant. "We find that the extinction was abrupt, not gradual," added University of Oxford paleontologist Roger Benson.

EE845C08-0BF8-40E0-9D98-7E69A0877F92_w640_r1_s.jpg

A fossil of an ichthyosaur is seen at the Jurassic Museum of Asturia in Colunga, northern Spain​

Streamlined design

Ichthyosaurs arose about 248 million years ago. They became key players in marine ecosystems while dinosaurs ruled the land. With a streamlined, dolphin-like body design, they were fast, efficient, air-breathing swimmers with muscular flippers and vertical tail flukes like sharks, not horizontal like whales and dolphins. They possessed unusually large eyes to spot fish, squid and similar prey in deep or turbid waters. They bore live babies rather than laying eggs. Some measured less than 3 feet (1 meter) long. Others achieved immense size like Shonisaurus, which lived about 210 million years ago and reached about 70 feet (21 meters). "Shonisaurus was probably the biggest animal that had appeared on Earth up to that point in time," Benson said.

The researchers performed a thorough examination of the ichthyosaur fossil record, reconstructing the group's evolutionary diversity, and scrutinized evidence of climate change coinciding with their extinction. Earth was warming rapidly, approaching the hottest times of the past 250 million years, triggering strong fluctuations in sea levels and temperatures. For a time, large swaths of seafloor became depleted in the oxygen necessary for animals to live. Fischer said these changes likely altered ichthyosaur migratory routes, food availability and birthing places. Other marine creatures including squid relatives and reef-building clams also suffered major losses. The research was published in the journal Nature Communications.

Mystery of Prehistoric Marine Reptile's Extinction Explained

See also:

Fossilized Lizard, 99 Million Years Old, a Clue to 'Lost Ecosystem'
March 07, 2016 - A fossilized lizard found in Southeast Asia preserved in amber dates back some 99 million years, Florida scientists have determined, making it the oldest specimen of its kind and a "missing link" for reptile researchers.
The lizard is some 75 million years older than the previous record holder, according to researchers at the Florida Museum of Natural History, who announced the finding this week. It was found decades ago in a mine along with other ancient, well-preserved reptile fossils, but the U.S. scientists were able to analyze the finds only recently. "It was incredibly exciting to see these animals for the first time," Edward Stanley, a member of the research team, said on Saturday. "It was exciting and startling, actually, how well they were preserved."

9E933601-CDF6-4680-B927-AF0B32B68918_w640_r1_s.jpg

Various lizard specimens are shown preserved in ancient amber from present-day Myanmar in Southeast Asia, in this handout photo provided by the Florida Museum of Natural History​

Scientists believe the chameleon-like creature was an infant when it was trapped in a gush of sticky resin while darting through a tropical forest in what is now Myanmar, in Southeast Asia. The creature's entire body, including its eyes and colorful scales, is unusually well-preserved, Stanley said. The other reptiles trapped in the amber, including a gecko and an arctic lizard, were also largely intact. Small reptiles have delicate bodies and typically deteriorate quickly, he said. Being encased in solid amber helped to lock the specimen together.

Stanley and other researchers used high-resolution digital X-ray technology to examine the creatures and estimate the age of the amber without breaking it. The discovery will help researchers learn more about the "lost ecosystem, the lost world" to which the creatures belonged, Stanley said, and it may help researchers learn more about the creatures' modern relatives. "It's kind of a missing link," Stanley said.

Fossilized Lizard, 99 Million Years Old, a Clue to 'Lost Ecosystem'
 

Forum List

Back
Top