- Fossil hunters on the Isle of Wight have unearthed bones
from the biggest dinosaur so far discovered in the UK.
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- One fossil - a single neck bone from the
125-130-million-year-old
sauropod dinosaur - measures an astonishing three-quarters of a metre in
length.
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- Based on this, a team of UK and US researchers believes
the huge reptile was probably over 20m long and could have weighed as much
as 40-50 tonnes.
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- Details of the discovery appear in the scientific journal
Cretaceous Research.
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- "It is impressively big," team leader Darren
Naish, of the University of Portsmouth, told the BBC News website.
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- The long-necked sauropods were the biggest and heaviest
group of dinosaurs in existence.
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- Physical features of the fossil suggest the British
creature
had similarities to two other known sauropods: Brachiosaurus and
Sauroposeidon
.
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- Cliff drop
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- The well-preserved cervical vertebra was found in 1992
along a stretch of beach between Chilton Chine and Sudmoor Point. It was
enclosed in a rock matrix called siderite.
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- "Siderite is very tough - it's an iron-impregnated
clay. After 125 million years or so, it sets like concrete. This enclosed
and protected the very fragile bone," explained Steve Hutt, of the
Dinosaur Isle museum, where the specimen is on display.
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- Mr Naish realised the fossil's importance in 2000 and
decided to describe it for publication in a scientific journal.
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- "The bone contains a wealth of information that
allowed us to work out with confidence exactly what sauropod it belonged
to. This, coupled with the giant size, was what attracted me to take a
further look," Mr Naish explained.
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- Fossil hunters have also discovered a second neck bone
that probably comes from the same animal. But this is less well preserved
and had been lying on the beach for some time, say researchers.
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- Scientists say the sauropod's skeleton had been eroding
out of nearby cliffs and there may be more remains still to be
found.
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- The fossils originate in the best known dinosaur-bearing
rock unit in the Isle of Wight - the so-called Wessex Formation.
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- This allowed the researchers to easily date the
plant-eater
to Lower Cretaceous times. It lived alongside other dinosaurs such as the
bulky, beaked Iguanodon and the fleet-footed, two-legged Hypsilophodon
.
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- Sized up
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- The bone is certainly amongst the biggest ever found
in Europe. But Mr Naish said as yet unpublished sauropod fossils from
Portugal
and Spain were even larger.
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- In February this year, researchers announced the
discovery
of fossilised bones from what would have been a 35m-long (about 115ft)
creature weighing 50 tonnes near Riodeva in eastern Spain.
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- "But given that until recently people didn't think
there were any big sauropods in the Lower Cretaceous, I think this is part
of a bigger story," said Mr Naish.
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- The world's biggest and heaviest dinosaur is commonly
said to be Argentinasaurus , a 37m-long (120ft), 80-100-tonne creature
known from South America.
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- However, a 2.4m-long (8ft) fossil vertebra from a
creature
called Amphicoelias fragillimus was pulled out of the Morrison Formation
of North America in 1877.
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- Based on the description of the bone made by its
discoverer
Edward Drinker Cope, the animal it belonged to would have been some 52m
(170ft) in length.
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- However, the huge specimen has since disappeared, which
makes this impossible to verify.
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- The vertebral bone described in the latest research paper
was found by fossil hunter Gavin Leng. It was cleaned up by David Cooper,
a volunteer at the Dinosaur Isle museum in Sandown, Isle of Wight.
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- © BBC MMIV
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- http://news.bbc.co.uk/2/hi/science/nature/4031789.stm
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