Minmi

Minmi was the first armoured ornithischian to be found in the Southern Hemisphere. It is named after Minmi Crossing, a place near the site in Queensland, Australia where the first skeleton was found. This herbivore has two peculiar features: bony rods grew backwards from unique, flat bony plates beside the neural spines of the dorsal vertebrae; and a mosaic of small scutes (bony plates) protected the belly. Minmi's classification is still uncertain. First placed in the nodosaurid family, it might prove to be a primitive ankylosaurid, or even part of a new, third family of armoured dinosaurs.

Minmi was a four-legged, armoured herbivore that stomped around on all four sturdy limbs, cutting off leafy fronds with its beak and chewing them between its small, leaf - shaped cheek teeth. Its body was thickly covered with armour that would have discouraged attack. Even a theropod that succeeded in overturning a Minmi risked snapping off its teeth against the belly armour.

The whole underside appears to have been covered with small, rounded scutes (bony plates) slightly over 5mm (about 1/4in) in diameter. It is possible that Minmi may have preferred running to passive resistance. This may have been facilitated by Minmi's most remarkable feature, which was not found in any other known ankylosaur. Beside each dorsal (back) vertebra there was a bony plate, known as a paravertebra, some 2cm (1/4in) long by 4cm (1 1/2in) wide. Attached to this was a rod of bone, which was similar to the bony tendons found in ornithopods. The rods might have reinforced the spine and eased the strain on it when the clumsy animal pounded the ground as it ran.

Two fossil skeletons have been discovered, both in Australia. The animals seem to have lived in open woodland, and both specimens seem to have been washed out to sea by rivers when they died, settling upside down on the seabed. Clay filled the body cavities, and then hard marine sediments encased the carcasses. Later still, the sea retreated to expose the rocks in which the fossils lay entombed.

Location: Australia

Diet: Low-growing plants

Size: Length 3m

Classification:

Family unknown

Infraorder Ankylosauria

Suborder Thyreophora

Order Ornithischia

Time (million years ago): 119-113