Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

What Happened to Dinosaurs' Predecessors After Earth's Largest Extinction 252 Million Years Ago?

30.04.2013
Predecessors to dinosaurs missed the race to fill habitats emptied when nine out of 10 species disappeared during Earth's largest mass extinction 252 million years ago.

Or did they?

That thinking was based on fossil records from sites in South Africa and southwest Russia.

It turns out, however, that scientists may have been looking in the wrong places.

Newly discovered fossils from 10 million years after the mass extinction reveal a lineage of animals thought to have led to dinosaurs in Tanzania and Zambia.

That's still millions of years before dinosaur relatives were seen in the fossil record elsewhere on Earth.

"The fossil record from the Karoo of South Africa, for example, is a good representation of four-legged land animals across southern Pangea before the extinction," says Christian Sidor, a paleontologist at the University of Washington.

Pangea was a landmass in which all the world's continents were once joined together. Southern Pangea was made up of what is today Africa, South America, Antarctica, Australia and India.

"After the extinction," says Sidor, "animals weren't as uniformly and widely distributed as before. We had to go looking in some fairly unorthodox places."

Sidor is the lead author of a paper reporting the findings; it appears in this week's issue of the journal Proceedings of the National Academy of Sciences.

The insights come from seven fossil-hunting expeditions in Tanzania, Zambia and Antarctica funded by the National Science Foundation (NSF). Additional work involved combing through existing fossil collections.

"These scientists have identified an outcome of mass extinctions--that species ecologically marginalized before the extinction may be 'freed up' to experience evolutionary bursts then dominate after the extinction," says H. Richard Lane, program director in NSF's Division of Earth Sciences.

The researchers created two "snapshots" of four-legged animals about five million years before, and again about 10 million years after, the extinction 252 million years ago.

Prior to the extinction, for example, the pig-sized Dicynodon--said to resemble a fat lizard with a short tail and turtle's head--was a dominant plant-eating species across southern Pangea.

After the mass extinction, Dicynodon disappeared. Related species were so greatly decreased in number that newly emerging herbivores could then compete with them.

"Groups that did well before the extinction didn't necessarily do well afterward," Sidor says.

The snapshot of life 10 million years after the extinction reveals that, among other things, archosaurs roamed in Tanzanian and Zambian basins, but weren't distributed across southern Pangea as had been the pattern for four-legged animals before the extinction.

Archosaurs, whose living relatives are birds and crocodilians, are of interest to scientists because it's thought that they led to animals like Asilisaurus, a dinosaur-like animal, and Nyasasaurus parringtoni, a dog-sized creature with a five-foot-long tail that could be the earliest dinosaur.

"Early archosaurs being found mainly in Tanzania is an example of how fragmented animal communities became after the extinction," Sidor says.

A new framework for analyzing biogeographic patterns from species distributions, developed by paper co-author Daril Vilhena of University of Washington, provided a way to discern the complex recovery.

It revealed that before the extinction, 35 percent of four-legged species were found in two or more of the five areas studied.

Some species' ranges stretched 1,600 miles (2,600 kilometers), encompassing the Tanzanian and South African basins.

Ten million years after the extinction, there was clear geographic clustering. Just seven percent of species were found in two or more regions.

The technique--a new way to statistically consider how connected or isolated species are from each other--could be useful to other paleontologists and to modern-day biogeographers, Sidor says.

Beginning in the early 2000s, he and his co-authors conducted expeditions to collect fossils from sites in Tanzania that hadn't been visited since the 1960s, and in Zambia where there had been little work since the 1980s.

Two expeditions to Antarctica provided additional finds, as did efforts to look at museum fossils that had not been fully documented or named.

The fossils turned out to hold a treasure trove of information, the scientists say, on life some 250 million years ago.

Other co-authors of the paper are Adam Huttenlocker, Brandon Peecook, Sterling Nesbitt and Linda Tsuji from University of Washington; Kenneth Angielczyk of the Field Museum of Natural History in Chicago; Roger Smith of the Iziko South African Museum in Cape Town; and Sébastien Steyer from the National Museum of Natural History in Paris.

The project was also funded by the National Geographic Society, Evolving Earth Foundation, the Grainger Foundation, the Field Museum/IDP Inc. African Partners Program, and the National Research Council of South Africa.

Media Contacts
Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov
Sandra Hines, UW (206) 543-2580 shines@uw.edu
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2012, its budget was $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov/news/news_summ.jsp?cntn_id=127749&org=NSF&from=news

More articles from Earth Sciences:

nachricht Novel method for investigating pore geometry in rocks
18.06.2018 | Kyushu University, I2CNER

nachricht Decades of satellite monitoring reveal Antarctic ice loss
14.06.2018 | University of Maryland

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

Im Focus: Water is not the same as water

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.

From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Novel method for investigating pore geometry in rocks

18.06.2018 | Earth Sciences

Diamond watch components

18.06.2018 | Process Engineering

New type of photosynthesis discovered

18.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>