232
WILLIAM MACNAE
areas apart from the northern Arabian Sea, and this rain is highly
seasonal in its occurrence. The mangroves, as a result, do not occupy
all the potential area available. Large areas of barren salt flats are
conspicuous. The fauna becomes limited to those animals with an
apparently wide euryhalinity.
The north-western coastline of Australia is recognized by Australian
zoogeographers as the “Dampierian Province” and its distinctness was
emphasized by Clark (1946) in studies of the echinoderms of northern
Australia. He ascribed the differences from the Queensland fauna t o
the isolation in the Pleistocene and later Tertiary provided by the
Sahul shelf coastline which extended far to the north. It would seem
to me that the open sea to the north would bring elements down from
Celebes, the Philippines and Japan to the shores of Sahul and these
would retreat to the present shore as the sea rose during the later
Pleistocene and recent times. It is for this reason that I have tentatively
included the Lesser Sunda Islands including Timor, although I have no
faunal lists from these regions.
Around Darwin and on other West Australian shores as far south
as Shark Bay the most conspicuous fiddler crab is a species of Uca, at
present undescribed, with legs of a brilliant orange red and back of a
dark reddish-purplish-brown, which occupied the niche occupied elsewhere by U . urvillei. It occurs among the pneumatophores in the
seaward fringes accompanied by U . dussumieri. This crab has not been
seen elsewhere, by myself or by Crane (personal communication). The
commonest of the smaller sesarmas has recently been described as new
by Campbell (1967). This is Sesarma (Chiromantes) darwinensis.
When visiting Australia I was considerably surprised to find myself
familiar with many of the animals on Queensland shores, but the fauna
on shores around Darwin was much less familiar. I was not there long
enough to pinpoint the differences.
7 . Division 8. Paci$c islands
The eighth division comprising the islands of the western Pacific is
a margin of subtraction. The closer to Indonesia the islands are the
more species characteristic of the Indo-Malayan mangals will be
present ; the farther out into the Ocean the fewer will be seen.
I n the Fiji group the Atlantic and east Pacific species Rhizophora
mangle is present as well as the west Pacific R. stylosa, (Guppy (1906)
records it as R. mucronata but his diagrams of the plants clearly apply
to R. stylosa; the two species were then not always distinguished).
A third form of Rhizophora also occurs; this is always sterile and
reproduces vegetatively. It may be a hybrid.
WILLIAM MACNAE
areas apart from the northern Arabian Sea, and this rain is highly
seasonal in its occurrence. The mangroves, as a result, do not occupy
all the potential area available. Large areas of barren salt flats are
conspicuous. The fauna becomes limited to those animals with an
apparently wide euryhalinity.
The north-western coastline of Australia is recognized by Australian
zoogeographers as the “Dampierian Province” and its distinctness was
emphasized by Clark (1946) in studies of the echinoderms of northern
Australia. He ascribed the differences from the Queensland fauna t o
the isolation in the Pleistocene and later Tertiary provided by the
Sahul shelf coastline which extended far to the north. It would seem
to me that the open sea to the north would bring elements down from
Celebes, the Philippines and Japan to the shores of Sahul and these
would retreat to the present shore as the sea rose during the later
Pleistocene and recent times. It is for this reason that I have tentatively
included the Lesser Sunda Islands including Timor, although I have no
faunal lists from these regions.
Around Darwin and on other West Australian shores as far south
as Shark Bay the most conspicuous fiddler crab is a species of Uca, at
present undescribed, with legs of a brilliant orange red and back of a
dark reddish-purplish-brown, which occupied the niche occupied elsewhere by U . urvillei. It occurs among the pneumatophores in the
seaward fringes accompanied by U . dussumieri. This crab has not been
seen elsewhere, by myself or by Crane (personal communication). The
commonest of the smaller sesarmas has recently been described as new
by Campbell (1967). This is Sesarma (Chiromantes) darwinensis.
When visiting Australia I was considerably surprised to find myself
familiar with many of the animals on Queensland shores, but the fauna
on shores around Darwin was much less familiar. I was not there long
enough to pinpoint the differences.
7 . Division 8. Paci$c islands
The eighth division comprising the islands of the western Pacific is
a margin of subtraction. The closer to Indonesia the islands are the
more species characteristic of the Indo-Malayan mangals will be
present ; the farther out into the Ocean the fewer will be seen.
I n the Fiji group the Atlantic and east Pacific species Rhizophora
mangle is present as well as the west Pacific R. stylosa, (Guppy (1906)
records it as R. mucronata but his diagrams of the plants clearly apply
to R. stylosa; the two species were then not always distinguished).
A third form of Rhizophora also occurs; this is always sterile and
reproduces vegetatively. It may be a hybrid.