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Public release date: 29-Apr-2013[ | E-mail |
Share ] Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
Fossil-hunting expeditions to Tanzania, Zambia and Antarctica provide new insights
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 for other paleontologists and for 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 Sbastien 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.
[ | E-mail | Share ] ?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Public release date: 29-Apr-2013[ | E-mail |
Share ] Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
Fossil-hunting expeditions to Tanzania, Zambia and Antarctica provide new insights
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 for other paleontologists and for 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 Sbastien 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.
[ | E-mail | Share ] ?
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Source: http://www.eurekalert.org/pub_releases/2013-04/nsf-wht042913.php
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The past 24 hours have just flown by for the hundreds of hackers here at the Disrupt NY Hackathon, but the sun is finally up and it’s time to pass judgment on their caffeine-fueled projects. As it turns out, there’s a ton of them here — with 164 registered projects this is our biggest Hackathon yet, and each presenter only had 60 seconds to wow our judges (not to mention the rest of the audience). As you might guess there was no shortage of amazing projects that came together in a single day, but our judges could only choose one team to take home our $5,000 grand prize. Anyway, that’s enough out of me — meet our newest Hackathon winner! Winner: Rambler Rambler, created by William Hockey, Zach Perret and Michael Kelly, is a web app that lets users view their credit and debit card transactions on a map. During the dev process, the team tapped the Foursquare API for locations and the Plaid API to access user spending data. Runner-up #1: Learn To Drive Learn To Drive, created by Jared Zoneraich, Jemma Issroff, Kenny Song, and Nicholas Joseph, is an app for the GM vehicle platform that acts as a virtual driving instructor by speaking driving instructions aloud and display driving statistics like miles driven, hours driven, and hours driven at night. Runner-up #2: Radical Radical, created by Sam Saccone, Carl Sednaoui, and Jeff Escalante, allows users to create attractive calendars and embed on webpages with a single line of code. These three teams will also demo their projects on the main Disrupt stage on Wednesday afternoon, but that’s not to say everyone else is going home empty-handed. Hackathon sponsors Appery.io, AT&T, CrunchBase, General Motors, Microsoft Bizspark, Microsoft Skydrive, NewAer, Pearson, Samsung, Twilio, Visa, Wrigley and Yammer have also graciously doled out prizes of their own for the most innovative and interesting uses of their APIs and services. And just who decided the fate of these sleep-deprived hackers? Our panel of judges includes Mahaya CEO Tarikh Korula, Path101 co-founder Charlie O?Donnell, founder/CEO of The Muse Kathryn Minshew, bit.ly chief?scientist?Hilary Mason, FuturePerfect Ventures founding partner Jalak Jobanputra, and TechStars NYC Managing Director David Tisch.