they are most famous for possessing tail-clubs. They existed
throughout the world approximately 170–65 million years ago
and are closely related to the stegosaurs.
Upon their return to Brisbane, the Queensland Museum
began work on the Ievers’ ankylosaur immediately. It turned out
that in the modern world this was to become not only Australia’s
most complete dinosaur skeleton but also one of the world’s best-
preserved ankylosaurs. Approximately 95% of the skeleton is
preserved, along with fossilised skin and the remains of the
animal’s last meal.
Despite its scientiic and geocultural signiicance, Molnar
was only able to publish a partial description of the Ievers’ anky-
losaur before retiring in the late 1990s. Molnar grouped it with
Minmi paravertebra, the only other ankylosaur then known
in Australia from fragmented remains discovered near Roma,
Queensland. And there it remained for the next 15 years.
MinmiGets a Makeover
Under the tutorage of Molnar and Dr Steve Salisbury of The
University of Queensland, I began my work on the Ievers’ anky-
losaur in 2007. This involved the description and interpreta-
tion of the skull bones as well as CT scanning at the Mater
Adult Hospital in Brisbane.
Our investigations revealed that the Richmond ankylosaur
discovered by the Ievers family was signiicantly distinct from
the Roma specimen of Minmi paravertebra, as well as from all
other known ankylosaurs, so we decided it warranted a new
name. Thus Kunbarrasaurus ieversiwas born. The word
“Kunbarra” (pronounced koon-ba-rah) means “shield” in the
Mayi language of the Wunumara people from the Richmond
area, while the species name honours its discoverer Mr Ian
Ievers, thus meaning “Ievers’ shield lizard”.Kunbarrasaurusvs the World
Ankylosaurs are known for their armour, which not only occurs
on the body but also extends onto the skull. In the majority of
ankylosaur skeletons so far described, this amazing feature is
so extensive that the individual bones of the skull are obscured
from view so that the skull appears to be formed from a single
bone. Therefore little is known about the coniguration of the
bones of the ankylosaur skull and its evolution.
Only four ankylosaur skulls exhibit sutures (junctions
between the skull bones) that enable the shape of the skull
bones to be examined. Kunbarrasaurusis one of these anky-
losaurs. Of the three remaining ankylosaur skulls one belongs
to Cedarpeltafrom North America, and the other two are juve-
nile specimens of a very advanced form of ankylosaur from
Mongolia called Pinacosaurus.
Cedarpeltaand Kunbarrasauruswere both found in Lower
Cretaceous rocks approximately 100 million years old. This is
a time in the early evolution of ankylosaurs from which little
is known. The majority of our knowledge on the early evolu-
tion of the group comes from isolated and fragmentary speci-
mens.
Despite this, current evidence suggests that the group was
beginning to diversify around this time. Although Cedarpelta
is contemporaneous with Kunbarrasaurus,it exhibits more
advanced ankylosaurian characteristics. On the other hand,
Kunbarrasaurusdisplays many features that are considered
primitive to the group as they are shared with its last common
ancestor, basal thyreophorans such as Scelidosaurus, and possibly
more so than any other known ankylosaur. It is thus an ideal
specimen in which to study the evolutionary transition between
ankylosaurs and their immediate ancestors.
The evolution of some key ankylosaurian features of the
skull have up until know been intelligently inferred. These
features include the loss of sutures and the occurrence of orna-
mentation on the skull, as well as closure of fenestrae and
foramina (openings in the skull that typically accommodate
muscles, blood vessels and nerves).
From comparisons with other ankylosaurs the development
of these features can be clearly seen in Kunbarrasaurus. For
example, the loss of sutures via fusion occurs from the back of
the skull and moves towards the snout. And the origin of orna-
mentation on the skull is formed through two different methods:
armour fusing to the skull bones along with remodelling of the
surface of individual skull bones. The closure of fenestrae and
foramina is due to the enlargement of bones, and not by them
being covered in armour.JUNE 2016|| 21The skeleton of Kunbarrasaurus ieversi,
Australia’s most complete dinosaur fossil.
Photograph © A. O’Toole & L. Leahey