Bulletin

Issue: April 2005

Research in Action

Fossilised faeces hit the fanfare

Coprolites—fossilised droppings from ancient creatures—are helping to provide information about the environment and the creatures which existed when Australia was part of the super continent Gondwana 250 million years ago.

La Trobe University palaeontologist, Dr Caroline Northwood, has published a paper in the January issue of Palaeontology, the journal of the British-based Palaeontological Association, on her research conclusions from examining Triassic age coprolites from two Queensland sites.

The Triassic Period occurred before the evolution of dinosaurs, birds or mammals, when amphibians were the most common semi-terrestrial tetrapods in this part of Gondwana.

Dr Northwood, who is senior grants officer in La Trobe’s Research and Graduate Studies office, wrote her PhD thesis on the palaeoecology of the Early Triassic Arcadia Formation in southern Queensland, under the supervision of La Trobe fossil amphibian specialist, Dr Anne Warren. The study of coprolites provided important evidence used in reconstructing the ancient ecology of the sites.

‘Not only do coprolites suggest the kinds of creatures and their diets but also the environment in which they lived,’ Dr Northwood said.

She amassed 2703 undamaged coprolites from one site known as The Crater and 1566 from the other, called Duckworth Creek, both in southern Queensland. Many thousands had been gathered in the 30 years that the site has been examined but before her study they were regarded by many scientists as mere curiosities.

Criteria used by other researchers to identify the creatures which produce fossilised scats at sites in the USA and elsewhere were found to be of little value in identifying the producers of the Queensland material.

However by using a combination of shape, size and food remains preserved in the coprolites, she managed to identify the source of some—but by no means all— of the thousands of coprolites.

The fossilised faeces were of three distinct categories, spiral, longitudinally striated, and indeterminate. None of the undamaged coprolites was less than 5mm in maximum length.

‘As invertebrate faecal pellets are generally smaller than this, the coprolites were probably produced by vertebrates’, she said.

She believes the spiral coprolites were produced by fish, the longitudinally striated by a three metre long reptile called Kalisuchus and most of the indeterminate coprolites by other carnivores including the common amphibians.

Invertebrate remains were rare in the coprolites but she found some which included insect wings, a segment of an insect head and other body parts. To identify these and other vertebrate remains such as scales, teeth, tooth plates and bones, she called on the assistance of zoology experts within La Trobe University, including Professor Tim New.

The presence of blue-green algae (cyanobacteria) in one coprolite provided evidence of an environment that could have been warm and dry and where local water sources periodically dried up.

In addition, the abundance of coprolites containing fish provided evidence of a rich fish fauna previously unknown in the Acadia Formation.

Dr Northwood said that despite their limitations, coprolites are clearly a valuable additional source of general palaeoecological information, particularly because components of the environment that would otherwise be rare or unknown are preserved.

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