EEP Crowned pigeon number 4

EEP STUDBOOK CROWNED PIGEONS
History of the island of New Guinea
Approximately 150 million years ago a southern landmass known as Gondwanaland started to
break up and its pieces drifted apart. Although this landmass included Antarctica, the climate
was far from polar and in fact this supercontinent had a well-developed fauna and flora under
at least temperate conditions. After the split, the components parts of Gondwanaland became
what are now known as South America, Africa, Madagascar, India, Australia, Southeast Asia,
New Zealand and Antarctica. Fifty-five million years ago Australia detached itself from
Antarctica and floated northwards and, as it approached the Asian continental land mass, it
caused a series of mountainous islands to be pushed up out of the sea. After a long,
complicated and still only partly understood geological history, these island chains joined
together to form New Guinea and other islands in the region (Menzies, 1991).
In the middle Tertiary (Miocene), the first vestige of the landmass was lifted above sea level,
but it was not until the great mountain-building phase of the Pliocene (5-6 million years ago)
that major portions of the island as we now know them, became established. New Guinea is
the product of an interaction between the northward moving Australian tectonic plate and the
Pacific plate, a movement that began in the middle Mesozoic. Forceful collision between the
two plates in the Tertiary is the probable cause for the mountain-building phase that produced
the complex of Central Ranges (Beehler, et al., 1986). For one or more periods during the ice
ages when sea levels were much lower than they are now, Australia was actually joined to
New Guinea and final separation only came less than one million years ago, with the
formation of the Torres Strait (Menzies, 1991).
Marsupials and monotremes and many other elements of the New Guinea fauna probably had
their origin in this ancestral southern land mass and were able to spread from Australia into
the newly emerging New Guinea and other islands, which were connected to Australia by
means of a land-bridge (Pratt, 1981), which is submerged now. On the other hand, other kinds
of mammals may have had their origin in a northern land mass and were cut off from the
southern continents until these land masses floated sufficiently close (about 15 million years
ago) for opportunistic invasions to take place. For this reason the islands, which formed
the‘collision zone’ between Australia and south-east Asia, including New Guinea, have been
a mixing place for marsupials and other kinds of mammals.
However, the New Guinean avifauna is predominantly Australian, since the island was
actually part of the continent for the most of its history (Pratt, 1981). The native mammal
fauna of the island of New Guinea is depauperate, meaning that many kinds of mammals
found in adjacent regions of the world are lacking here. New Guinea’s mammal fauna is made
up, apart from flying foxes and other kinds of bats, of two kinds of monotremes, and
approximately equal numbers (around 60) of species of marsupials (pouched mammals) and
rodents but this conceals the fact that the marsupials are far more diverse. The rodents are
represented by just one family: rats and mice (Muridae).
On the other hand there are seven families of marsupials ranging from tiny mouse-sized
carnivores to large, herbivorous kangaroos. In Australia the composition of the endemic
terrestrial mammalian fauna is just the same: monotremes, marsupials and rodents, but the
rats and mice are now quite outnumbered by more than 120 species of marsupials in 13
separate families. There are 6 different families of bats in New Guinea as well but bats have
fewer restrictions on their movements and many kinds are very widely distributed outside the
region (Menzies, 1991).
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