Australia: The Land Where Time Began

A biography of the Australian continent 

The overall shape and features of the skull indicate the Chugutosauridae are closely related to the Brachiopidae. Not many genera of this family are known, 2 from India - Compsocerops, Kuttycephalus, 1 from South America, Pelorocephalus,  and 3 from Australia, Keratobrachyops and Siderops, and an undescribed amphibian from the Cretaceous of Victorian .

This family is characterised by a number of proportional ranges and anatomical features. On their own, these features don't appear to be unique to this group, it is only in constellations of features that they become indicators of family membership.

Chigutosaurids appear similar to Brachiopids in skull form, but differ from them in possessing well-developed tabular horns, smaller eye sockets, many small teeth, the Brachyopids have fewer larger teeth. The 2 families also differ in a number of palatal features.

Keratobrachyops australis

Like other amphibian skulls from the Arcadia Formation, this specimen was found weathering out of the red siltstone. All known specimens were found within 1 m of the type skull Brachyops allos, and within 3 m of each other. It was the first known Australian amphibian of the Brachyopoidea superfamily to have horns. It was about 1 m long, the skull was narrow for a Brachyopoid, slightly broader than long, and deeper than other Chigutisaurid skulls. The largest known skull is 13.5 cm wide.

The horns project from the tabular bones, the bone surface being covered with fine dermal ridges. The palate indicates that teeth are present, there is no palatoquadrate fissure, the exoccipital and pterygoid don't  make contact, and the tooth-bearing maxilla enters the margin of the choana (internal nostril).

Sources & Further reading

1. John A Long, Dinosaurs of Australia and New Zealand, University of New South Wales Press

Ampibian Deposits