#Snail without shell series#

The age of the snail can easily be assessed by counting the number of winter breaks and add- ing this to the yearly increments.

Support for the research was provided by the Natural Environmental Research Council. The older the snail, the thicker is the lip, the shell colour is lighter and the shell surface, between the lateral lip bases is whiter. Siveter of the University of Oxford and Julia D. Siveter of the University of Leicester, Derek J. The other authors of the paper are David J.

#Snail without shell series#

Kulindroplax is coined from the Greek words for a cylinder and a plate, referring to the rounded body with its series of shells. In addition to its seven shells, Kulindroplax had a dense covering of spicules over the rest of the body, which it probably used to gain purchase as it crawled on the muddy sea bed. The researchers later reconstructed its three-dimensional shape using computer software, revealing both form and structure in fine detail. About 2 cm wide and 4 cm long, Kulindroplax was buried in volcanic ash deposited on the sea floor. The researchers found the specimen of Kulindroplax more than 10 years ago in the Herefordshire fossil deposit, a rich assemblage of ancient marine life forms more than 400 million years old. Sutton of Imperial College London, the paper's lead-author.

Kulindroplax represents the first mollusk with an unambiguous combination of valves, or exterior shells, and a worm-like body, said Mark D. Previously thought to be a product of the explosion of diversity during the early Cambrian period, they are now shown to have evolved probably 40-50 million years ago by losing shells like those on Kulindroplax. The evolutionary relationships of worm-like mollusks, known as Aplacophora, has been a subject of controversy. The researchers report their findings online Oct. Briggs, director of the Yale Peabody Museum of Natural History and one of the paleontologists who studied the new fossil, Kulindroplax perissokomos. 'This is a kind of missing link with a worm-like body, bearing a series of shells like those of a chiton or coat-of-mail shell,' said Derek E. The discovery reinforces previous findings from molecular sequencing studies and helps clarify the evolutionary relationships of mollusks, a broad category that includes not only oysters and mussels but also slugs, squids and octopuses. The small new fossil, found in marine rocks along the English-Welsh border, provides the best fossil evidence yet that the simpler worm-like mollusks evolved from their more anatomically complex shelled brethren, rather than the other way around.