Thursday, July 31, 2014

Coprolites – Indicate Former Presence of Organism

Coprolites are the preservation or fossilization of the matter of intestine and the excrement of organisms or it could be termed as fossilized faeces and are rare since they decay easily and if located, they are found among sea organisms.

Since they are fossilized faeces, coprolite indicate the former presence of organisms in the vicinity they are found but it does not indicate the exact organism present though in most cases, there are exception as in the case of the shark who have distinctive character of spiral valves in their intestines.

The shark coprolite has grooves which are made by spiral valves and when the organism indicate these distinctive characters, it tends to be possible in classifying the organism with coprolite though it becomes a bit hard to link faeces with certain organism. Its name is derived from a Greek word `kopros’ which means dung and `lithos’ which means stone.

It was first described by William Buckland, the geologist, in 1829 before which they were known as fossil fir cones and bezoar stones. These provided valuable information in paleontology since they gave evidence to the predation and diet of extinct organism and Coprolites vary in size from a few millimetres to over 60 centimetres.

Recognition – Structural Pattern

Recognition of coprolites is supported by their structural patterns like in the case of spiral or annular marking, as in undigested food fragments, by their content and by associated fossil matter and smallest coprolites are difficult to classify from inorganic pellets or from eggs.

Mostly the coprolites contents are of calcium phosphate together with small quantities of organic matter and on analysing them, it indicates the diet of the animal from which it came from.

Coprolites have been found in deposits varying in age from the Cambrian era to recent times and are also found all over the world and some of them tend to be useful as index fossils like the Favreina during the Jurassic period of Haute Savoie in France.

Coprolites are very important in understanding the diet of the organism and also an indicator of the ecosystem surrounding the organism. On researching on the coprolites and its contents, it conveys where the organism lived, like in the case of Ichthyosaurs, extinct, aquatic fish like reptiles.

Mary Anning’s Observation & William Buckland Belief

Coprolite with the internal skeletons of two hundred belemnites – a conical fossil shell of an extinct cephalopod, together with fish scales and bones were discovered in the Ichthyosaur which indicated that they lived among fish and cephalopods.

Coprolite are very valuable than their paleontologic value and there are many who treasure them as gifts. Mary Anning, the fossil hunter noticed that bezoar stones were found mostly in the abdominal region of ichthyosaur skeletons in the Lias formation at Lyme Regis and noted that if these stones were broken open, they would contain fossilized fish bones and scales and at times bones from small ichthyosaurs.

These observations of Anning led William Buckland, to believe that the stones were fossilized faeces and called them Coprolites. He also presumed that the spiral marking on the fossils showed that ichthyosaurs with spiral ridges in their intestines were same to those of modern shark with some of these coprolites were black with ink which were swallowed belemnites.

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