|The Gobi Desert is very similar to Britain when |
it was part of the red continent of Pangaea
Despite all this the British Isles have contributed little to the world of palaeontology. While Britain is small in size, it has a rich geological mix which should have produced many marvels. Yet some do exist. The Rhynie Chert in Scotland preserves the remains of the oldest terrestrial ecosystem on the planet. While further north, rocks have revealed the complete armour from the largest sea scorpion ever found.
A single fossil, recovered from Silurian rocks on the England/Wales border has cleared up a major discrepancy on the evolutionary history of molluscs: namely whether such creatures first evolved with or without a shell. The fossil is a of a creature, Kulindroplax perissokomox, buried in volcanic ash 400 million years ago, and present in our collections for over 10 years. 2 centimetres in diameter and 4 centimetres in length, Kulindroplax has the body-shape of a worm.
What makes it important is that it was covered in a series of scale-shaped, interlocking plates which ran along the length of its back. Using scanning and modelling software, researchers led by Mark. D. Sutton from Imperial College, London, were able to look closer at the fossil. In addition to the seven plates, Kulindroplax had a covering of small pointed rods on the underside of its body which would have allowed it to gain extra purchase on the muddy sea floor which was its home.
|The 400 million year old fossil of Kulindroplax perissokomox. |
The coloured sections show the position of the seven interlocking plates
It seems that the hard shells evolved first and that soft bodied molluscs, rather than making an appearance during the Cambrian explosion, as was previously thought, are actually rather more recent, coming into the picture only 50 million years ago with the loss of their shells. Today molluscs are an incredibly diverse group with a rich evolutionary history stretching back to even before the Cambrian period. Their ancient shells now form the rocks of the Earth and the buildings around us today; Kulindroplax plays a major part in that story.