By Eddie Wrenn
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The 'missing link' which proves the relationship between dinosaurs and birds may have been found.
It is a widely-held view that dinosaurs and birds share the same heritage, and an egg discovered in the Montsec area of Lleida, near Catalonia in Eastern Spain, shares characteristics of both species.
The dinosaur egg, dating back 70 to 83 million years, has an oval shape, similar in appearance to a chicken egg, and an 'air bag' inside which birds today use to breathe in the last stages of its development.
The new type of dinosaur egg has been given the scientific name of Sankofa pyrenaica and is the only dinosaur egg in the world to have an oval shape, similar to that of chicken eggs.
The brood: The eggs, found in easter Spain, are quite large, and bear similarities to the breakfast variety
Spot the difference: A chicken egg
Nieves Lpez Martnez, palaeontologist of the Complutense University of Madrid, was working on the research of dinosaur eggs before her death in December 2010.
Together with Enric Vicens, palaeontologist of the Universitat Autnoma de Barcelona, the two scientists conducted an exhaustive analysis of their discovery, now published in the journal Palaeontology.
The South Pyrenean area is rich in dinosaur egg sites, most of which correspond to sauropod eggs from the upper Cretaceous, dating back more than 70 million years ago.
During that period, the area was a coastal area full of beaches and deltas which won land from the sea through sediment accumulation.
Sand and mud from that period gave way, millions of years later, to the sandstone and marl where dinosaur remains now can be found. On the beach ridges and flat coastal lands is where a large group of dinosaurs laid their eggs.
The sites where the discoveries were made correspond to the upper Cretaceous, between the Campanian and Maastrichtian periods, some 70 to 83 million years ago.
The fossils found belong to small eggs measuring some 7 centimetres tall and 4 cm wide, while the eggshell was on average 0.27mm thick.
Most of the eggs found were broken in small fragments, but scientists also discovered more or less complete eggs, which can be easily studied in sections.
The eggs found at the sites all belong to the same species. The main difference when compared to other eggs from the same period is their asymmetrical shape, similar to that of chicken eggs.
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The more complete samples clearly show an oval form rarely seen in eggs from the upper Cretaceous period and similar to modern day eggs.
Their shape is a unique characteristic of theropod eggs from the upper Cretaceous period and suggests a connection with bird eggs.
Non-avian dinosaur eggs are symmetrical and elongated. Asymmetry in bird eggs is associated to the physiology of birds: they take on this shape given the existence of only one oviduct which can form only one egg at a time.
In this case the isthmus, the region in the oviduct creating the eggshell membrane, is what gives the egg its asymmetrical shape.
Thanks to this shape, the wider end contains a bag of air which allows the bird to breathe in the last stages of its development. This evolutionary step was still relatively underdeveloped in dinosaurs.
Thus, the egg discovered by UCM and UAB researchers in certain manners represents the missing link between dinosaurs and birds.
Only one other egg, discovered in Argentina and corresponding to a primitive bird from the same period, has similar characteristics.
The discover represents proof in favour of the hypothesis that non-avian theropods, the dinosaurs of the Cretaceous period, and birds could have had a common ancestor.
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@Open eye --- When acid is added to calcium the calcium 'reacts'. Does this mean that calcium has 'intelligence'? Also what about the information thing?
somewhere else in American @ what do you mean when you say the cell is not intelligent it just occurs naturally ? nothing appears out of no where by itself, nothing behaves in the way it does if it did not have input, parameters and boundaries to regulate its behaviour, as a scientists you can only observed this behaviour but you cannot explain why they behave that way all the time and not differently, as a result you have no basis to declare that the cell has no intelligence for you have no idea of its behaviour origins, it is beyond you so much so that if you knew molecular and nano research would be light years ahead of where it is now, cells do have intelligence if they did not, when conditions change around them they would be stationary and not react at all.
OK... which came first.... the dinosaur..... or the egg?
Until we find the remains of every single organism that has ever lived, there will always be missing links. Clearly impossible, so the creationists will always have this stupid argument available.
Maybe it IS just an ancient chicken egg and chickens are FAR older than we think......I think scientists sometimes overlook the obvious and really can't think outside of the box they've constructed. .
Open Eyes ----- Do single cell organisms loose or gain information when they divide?
- Open Eyes, London;...."the cell has to be intelligent at first to change and when it does change it never gets new information it looses it" I am a molecular biologist. I have read posts from this guy, and it is clear that he has never taken a class or opened a text on this subject. First, cells are not "intelligent", that is just obsurd, and within seconds I could name 5 ways the genetic material of a cell gains new information instead of just losing it. Recombination, chimerism, single and double point mutations, codon translocation error. There are more. Most these ocurr naturally. Others are often corrected in the cell, but all can result in additions to genes and can result in new proteins being formed. It is amazing to me that these creationists find this science SOO important, but never take the time to open a book to see if what they are saying, with oh so much certainty, is actually gibberish. An undergrad that has taken a single course would laugh to read their assertions.
Open Eyes --- Please explain how 'information' is lost when a cell 'changes'.
@Steve, you still have side step the point the cell has to be intelligent at first to change and when it does change it never gets new information it looses it,
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To Open Eyes, 14/07/ - 23:14 -- A cell behaves the way that it does because the component molecules are engaging in chemical reactions. These occur because each molecule obeys the laws of thermodynamics. It all looks very clever and seemingly directed to the ignorant but actually, it is a totally mindless process which will happen automatically whenever the conditions are right. These reactions will (and do) occur outside the cell in a test tube but - it is they which constitute life. This is exactly the same mechanism which drove the formation of the precursor molecules from common compounds in the process that is now known as abiogenesis. By your insistence that cells (but actually their component molecules) have some sort of "intelligence" or "driving force", you are admitting to the existence of the very force which you have hitherto disputed. You thereby demonstrate that life can indeed arise spontaneously.
- EB, Milton Keynes, 15/7/2012 00:52
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