sharing the past - Auckland Museum

Sharing the Past
Elasmosaurs may have come ashore to lay eggs
as modern turtles do. Juvenile Elasmosaurs spent
their early years in warm, shallow water close to
shore and possibly escaped onto the beach to
avoid storms or predators. Elasmosaurs became
extinct along with the rest of the marine reptiles
and dinosaurs at the end of the Cretaceous (65
million years ago).
On its death this
particular adult
sank to the ocean
bottom and settled
into the sandy mud.
Even while the
bloated flesh was
being stripped
from the carcass by
scavenging organisms,
sediment
began to cover the
12 metres of the
remains. Sections
of the skeleton
formed the nucleus
of several spherical
concretions.
Concretions, like
the Moeraki
Boulders, are lay-
9 Teacher Background
Auckland Museum
Te Papa Whakahiku
THE SAGA OF THE KAIKOURA PLESIOSAUR
teacher background
70 million years ago an adult Elasmosaur (a long necked plesiosaur)
identified as Mauisaurus haasti was living in the
ancient Pacific Ocean close to the outer continental shelf.
Elasmosaurs, the largest of the
marine reptiles, were extremely
agile swimmers. Long, strong
necks meant that their heads were able to twist
and turn quickly in search of food; to lunge out and
skewer fish, squid or birds between interlocking, sharp teeth.
ers of cemented sandstone wrapped like an
onion around a nucleus and vary from a few
millimetres to boulder size. The Museum's concretion
formed around the ribs and pelvic girdle of
Mauisaurus haasti.
About 25 million years ago, plate tectonics or
movement of the earth's crust, caused the seabed
Mike Eagle leans against half of the huge concretion destined for Auckland Museum. The
other half lies further down near his feet.