Australia: The Land Where Time Began

A biography of the Australian continent 

Fossil tetrapod tracks have been found in the Genoa River Beds in eastern Victoria. There are 3 sets of tetrapod tracks associated with rocks in which were found the stems of sphenopsids and Archaeopteris howittii, the foliage of which were fern-like. The preservation of the tracks were of variable quality, the best indicating that the animal was about 550 mm long. From the tracks it could be determined that the feet had 5 digits, most of the length of the digits being covered by webbing. There were at least 3 digits on the hand, though the number is uncertain, but it could possibly have had more. The foot was slightly larger than the hand, being about 3.5 cm at its widest.

There was a body and tail trace associated with another of the trackways, the feet not overstepping the prints of the hands. The locomotion of this animal is believed to have been by undulating movement of the body and tail, at least partially, as the impressions of the hind feet didn't overstep those of the hands. At 17.5 cm the pace was at least twice as long as that of the earliest known tracemaker.

No skeletal remains have been found in the vicinity of the tracks, so the animal making the tracks cannot be known. Skeletal remains of tetrapods are known from the Late Devonian of Greenland, the best being an Ichthyostega that was about 1 m long . This specimen had 5 short digits on its foot that was 3.5 cm wide.

It seems likely just such an animal could have made the trackways in the Genoa River Beds.

Sources & Further reading

Patricia Vickers-Rich, Thomas Hewitt Rich, Wildlife of Gondwana, Reed Australia, 1993