6
B. K. DELL
with this continent, some in the ocean basins around its periphery.
It is probable that this latter group is better considered in relation to
world abyssal faunas, rather than as part of a specific Antarctic fauna.
Such evidence as is available points in this direction. The Antarctic
Circle is a geographical abstraction, not a biological boundary, even for
terrestrial organisms.
The coastal area of the Antarctic Continent itself proves to be an
equally unsatisfactory boundary for a specific Antarctic benthic biota.
The islands of the South Shetlands are so closely associated with the
Antarctic Peninsula geographically and faunally that these must be
included. However, a large part of the plants and animals living within
this area is not confined to it but extends to varying degrees, particularly through the islands of the Scotia Arc.
The one physical boundary which has proved a particularly useful
biological boundary especially for the organisms living in the surface
waters of the Southern Ocean has been the Antarctic Convergence. The
position of the Convergence fluctuates throughout the year, and from
year to year, but this creates no major problems in delineating the
distribution of planktonic organisms and for those animals dependent
upon the plankton. The literature on the relationship of plankton to
the waters on both sides of the Antarctic Convergence is considerable
and has a vast literature of its own. A recent summary is that of
Mackintosh (1960).
Many of the attempts to delimit the Antarctic Region seem to be
based upon the wrong criteria. In a biogeographical discussion, the
evidence for subdivision should be essentially faunal. The primary task
should be to determine what the animals do, and where they occur,
rather than how well they conform to some stated scheme, however
logical this may be. Kusakin (1968, p. 355) criticizes rather scathingly
“ the excessively pedantic utilization of the zonal-geographical method
at the expense of the faunistic (or floristic) method ”. In considering
the benthos, there seems no reason why the Antarctic Convergence
should be a benthic boundary except in a very indirect way. In group
after group the Antarctic fauna, or appreciable elements of it, extends
along the island groups of the Scotia Arc as far as South Georgia. But
most of the evidence we have is for the narrow continental shelf and
the continental slope and the shelves and slopes around the islands.
Except in the region of the Scotia Arc, the Antarctic shelf fauna cannot
extend as far north as the Antarctic Convergence. The distinction is
well shown in Hedgpeth (1969a, p. 6, Fig. 10) where the area within the
Antarctic Convergence (i.e. the “Antarctic Region ”) is far greater in
extent than the ‘‘ Continental Subregion ”. The abyssal faunas of the
B. K. DELL
with this continent, some in the ocean basins around its periphery.
It is probable that this latter group is better considered in relation to
world abyssal faunas, rather than as part of a specific Antarctic fauna.
Such evidence as is available points in this direction. The Antarctic
Circle is a geographical abstraction, not a biological boundary, even for
terrestrial organisms.
The coastal area of the Antarctic Continent itself proves to be an
equally unsatisfactory boundary for a specific Antarctic benthic biota.
The islands of the South Shetlands are so closely associated with the
Antarctic Peninsula geographically and faunally that these must be
included. However, a large part of the plants and animals living within
this area is not confined to it but extends to varying degrees, particularly through the islands of the Scotia Arc.
The one physical boundary which has proved a particularly useful
biological boundary especially for the organisms living in the surface
waters of the Southern Ocean has been the Antarctic Convergence. The
position of the Convergence fluctuates throughout the year, and from
year to year, but this creates no major problems in delineating the
distribution of planktonic organisms and for those animals dependent
upon the plankton. The literature on the relationship of plankton to
the waters on both sides of the Antarctic Convergence is considerable
and has a vast literature of its own. A recent summary is that of
Mackintosh (1960).
Many of the attempts to delimit the Antarctic Region seem to be
based upon the wrong criteria. In a biogeographical discussion, the
evidence for subdivision should be essentially faunal. The primary task
should be to determine what the animals do, and where they occur,
rather than how well they conform to some stated scheme, however
logical this may be. Kusakin (1968, p. 355) criticizes rather scathingly
“ the excessively pedantic utilization of the zonal-geographical method
at the expense of the faunistic (or floristic) method ”. In considering
the benthos, there seems no reason why the Antarctic Convergence
should be a benthic boundary except in a very indirect way. In group
after group the Antarctic fauna, or appreciable elements of it, extends
along the island groups of the Scotia Arc as far as South Georgia. But
most of the evidence we have is for the narrow continental shelf and
the continental slope and the shelves and slopes around the islands.
Except in the region of the Scotia Arc, the Antarctic shelf fauna cannot
extend as far north as the Antarctic Convergence. The distinction is
well shown in Hedgpeth (1969a, p. 6, Fig. 10) where the area within the
Antarctic Convergence (i.e. the “Antarctic Region ”) is far greater in
extent than the ‘‘ Continental Subregion ”. The abyssal faunas of the