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TOPIC: Ancient fossils
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Sirenia
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Title: Cranial Remain from Tunisia Provides New Clues for the Origin and Evolution of Sirenia (Mammalia, Afrotheria) in Africa
Authors: Benoit J, Adnet S, El Mabrouk E, Khayati H, Ben Haj Ali M, et al. (2013)

Sea cows (manatees, dugongs) are the only living marine mammals to feed solely on aquatic plants. Unlike whales or dolphins (Cetacea), the earliest evolutionary history of sirenians is poorly documented, and limited to a few fossils including skulls and skeletons of two genera composing the stem family of Prorastomidae (Prorastomus and Pezosiren). Surprisingly, these fossils come from the Eocene of Jamaica, while stem Hyracoidea and Proboscidea - the putative sister-groups to Sirenia - are recorded in Africa as early as the Late Paleocene. So far, the historical biogeography of early Sirenia has remained obscure given this paradox between phylogeny and fossil record. Here we use X-ray microtomography to investigate a newly discovered sirenian petrosal from the Eocene of Tunisia. This fossil represents the oldest occurrence of sirenians in Africa. The morphology of this petrosal is more primitive than the Jamaican prorastomids' one, which emphasises the basal position of this new African taxon within the Sirenia clade. This discovery testifies to the great antiquity of Sirenia in Africa, and therefore supports their African origin. While isotopic analyses previously suggested sirenians had adapted directly to the marine environment, new paleoenvironmental evidence suggests that basal-most sea cows were likely restricted to fresh waters.

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Blobrana


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RE: Ancient fossils
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Prehistoric ghosts revealing new details

Scientists at The University of Manchester have used synchrotron-based imaging techniques to identify previously unseen anatomy preserved in fossils.
Their work on a 50 million year old lizard skin identified the presence of teeth (invisible to visible light), demonstrating for the first time that this fossil animal was more than just a skin moult. This was only possible using some of the brightest light in the universe, x-rays generated by a synchrotron.
Dr Phil Manning, Dr Nick Edwards, Dr Roy Wogelius and colleagues from the Palaeontology Research group used Synchrotron Rapid Screening X-ray Fluorescence at the Stanford Synchrotron Radiation Lightsource in California to map the chemical make up of a rare fossil lizard skin. This cutting edge technology uses powerful x-rays that enabled the team to map the presence of phosphorus from teeth in this ancient reptile.
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Blobrana


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Castle Rock family finds 64 million-year-old fossils in back yard

On a recent hot summer day, while digging a sand box in their back yard, Troy Carmann and sons Grant and Winston found 64 million year old fossils.
Ian Miller is with the Denver Museum of Nature and Science. He says the find is significant in that it is just up the road from one of the best flora finds ever, which was made at the Wolfensberger exit on I-25 back in 1997.
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London's fossils: An ancient world hidden in the city

Issy Gilbert, a palaeontology PhD student from Imperial College London, reveals the ancient world that can be found at some of London's most famous destinations.
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Blobrana


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Buried in the deserts of the world are fossils of trees and animals that died millions of years ago. Those fossils are often made of packed sediment. Occasionally, that sediment is uranium.
A lot of old fossils are filled to the brim with uranium that has a high percentage of U-235.
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It is not unusual for fossils to contain elevated levels of uranium and its associated decay products. This is particularly true for those parts of the country rich in uranium deposits (for example, the Morrison formation). Uranium from the ore will dissolve in the local groundwater and when the latter comes into contact with porous organic material, such as a buried tree trunk or dinosaur bone, the uranium precipitates (the precise chemistry is not something I have information about). Over time, the replacement of the organic material by uranium can become substantial.
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Palaeontologists found about 300 well-preserved fossils of pre-historic animals at two quarries outside Buenos Aires, Argentine officials said.
The fossils were found by specialists from the University of La Plata in a 1,000 sq. meter lot in Marcos Paz, a city about 40 km from the capital.
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British scientists find 'lost' Charles Darwin fossils

British scientists have found scores of fossils the great evolutionary theorist Charles Darwin and his peers collected but that had been lost for more than 150 years.
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A "treasure trove" of fossils - including some collected by Charles Darwin - has been re-discovered in an old cabinet.

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Fossil 'is first pregnant lizard'

A 120-million-year-old fossil is the oldest pregnant lizard ever discovered, according to scientists.
The fossil, found in China, is a very complete 30cm lizard with more than a dozen embryos in its body.
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Oakville man finds 445-million-year-old fossils

When Keith Lihou's shovel hit a slab of limestone, the Oakville developer's first thought was how nice the smooth, grey rocks would look in his garden.
But after prying a few pieces out of the clay and carefully rinsing them off, Mr. Lihou realized he had found something much more interesting.
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