Found fossils 500 million years of snail relatives

Fossils of a snail-like creature, living in the seabed 500 million years ago, have revealed light on the origin of modern snails, shellfish and squid species.

The most comprehensive analysis so far about fossil portions shows that they are linked to modern mollusks, scientists wrote in the weekly Proceedings of the Royal Society B.

Called Wiwaxia and Odontogriphus , the location of these fossils lies in the evolutionary ladder that has been debated for years. It is debated whether they are molluscs living in the early period, distant relatives of the earthworm or a strange species of extinction.

Using the new microscope technology, Martin Smith, a graduate student at the Department of Evolutionary Biology at the University of Toronto, discovered that the organism has a feeding mechanism like modern mollusks.

Modern snails

"The mouths of their mouths are similar to those of the teething sea lilies, with a conveyor-belt feed collectors very similar to most modern molluscs" - he said - "Based on systematic evaluation "teeth" system, I believe they represent modern mollusks ".

Group of molluscs, including all kinds of octopus, sons, oysters . is the second largest single group of animals. However, little is known about the early stages of their evolution. Odontogriphus was once an unshelled snail with a length of up to 15cm while Wiwaxia was 1mm to 5cmm long with prongs and scales.

These invertebrates are found in British Columbia, Canada with their fossils dating back about 505 million years. To study fossils, Smith used electron microscopy, with a resolution of 1,000 times better than current light microscopes, to examine details of the fossil's mouth area.

Only recently has it been possible to create a microscope that allows large fossils to be examined without damaging them.

The scientists concluded that Wiwaxia and Odontogriphus had 2-3 rows of teeth from 17-33 of the same size, with a central tooth fairly balanced and many smaller teeth on the edge. These teeth can move around a tongue according to the way the carnivorous mollusks work today. It will help collect seaweed and organic waste from the seabed.

"I see no reason to suspect they are not molluscs," Smith said.

It is not clear whether these fossils are the direct ancestors of modern molluscs. It is possible to have several creatures of similar shape living with Wiwaxia and Odontogriphus. But since these species cannot mate with each other, only one of them grows into modern snails.

"It is very likely that Odontogriphus or Wiwaxia are the ancestors of the snail. But they are likely to be relatively close relatives, a branch separated from the seed line that created all modern mollusks," Smith said. .