ANTARCTIC BENTHOS
37
continental run-off oceanic waters extend right to the edge of the
continent, allowing sponges from deeper water to occur in shallow
water close inshore. The glass sponges are typically oceanic forms
found only at depths greater than 100 m, but in the Antarctic they may
be abundant near the coast even in water as shallow as 10m. The
presence of bottom currents flowing from the continent outwards and
downwards also tends to produce a uniform sponge fauna with no
zonal distribution developed between 100 and 900 m.
More than half the species recorded from the Antarctic (in the
wide sense used by Koltun including also most of the Subantarctic) are
endemic. Generic endemism is much less marked. Some 116 genera are
known in the Antarctic. Of these only nine (Koltun, 1970) can be considered to be endemic, Scolymastra, Acanthorhabdus, Hoplakithara,
Cercidochela, Meliidermu, Crellina, Bipocillopsis, Acanthoxa, and
Cladothenea.
Most of the Antarctic species of sponges belong to genera which are
well represented in the seas of the world, e.g. Mycale, Asbestopluma,
Myxilla, Tedania, Iophon, Hymedesmia, Isodictya, Anchinoe, Haliclona,
Adocia, and Hymeniacidon.
As in many other groups many sponges have a circum-Antarctic
distribution. The commonest species in this group are : Rossella antarctica Carter, R . racovitzae Topsent, Scolymastra joubini, Cinachyra
antarctica Carter, Tetilla leptodermu Sollas, Mycule tridens Hentschel,
M . acerata Kirkpatrick, Asbestopluma belgicae Topsent, Iophon radiatus
Topsent, I . spatulatus Kirkpatrick, Acanthorhabdus fragilis Burton,
Cercidochela lankesteri Kirkpatrick, Tedania masaa Ridley and Dendy,
T . oxeata Topsent, Axociella nidijcuta Kirkpatrick, Isodictya erinacea
Topsent, Ectyodoryx ramilobosa ( Topsent), Eurypon miniaceum Thiele
and Microxina benedeni (Topsent), (Koltun, 1964).
Koltun has shown that there are, however, marked differences
between the faunas of East and West Antarctica. McMurdo Sound in
the Ross Sea is the only area in Antarctica from which representatives
of Stelletta, Geodinella, Jmpis, Penares, Hemiasterella, Rhabderemia,
Chondropsis, and Dysidea have been collected (Burton, 1929). Other
species, e.g. Hoplakithara dendyi Kirkpatrick, Plocumia gaussiana
Hentschel, Clathria pauper Brondsted, Sphaerotylus schoenus Sollas,
Dolichancanthu macrodon Hentschel, Desmucella vestibularis Wilson
and Monoggringa longispinu von Lendenfeld have a wider distribution
but are still confined to Emt Antarctica.
Many fewer species are endemic to West Antarctica, e.g. Mycale
macrochela Burton, M . tylotornota Koltun, Isodactyla toxiphila Burton,
Myxilla australis Topsent, M . piatillaris Topsent, and Hymeniacidon
37
continental run-off oceanic waters extend right to the edge of the
continent, allowing sponges from deeper water to occur in shallow
water close inshore. The glass sponges are typically oceanic forms
found only at depths greater than 100 m, but in the Antarctic they may
be abundant near the coast even in water as shallow as 10m. The
presence of bottom currents flowing from the continent outwards and
downwards also tends to produce a uniform sponge fauna with no
zonal distribution developed between 100 and 900 m.
More than half the species recorded from the Antarctic (in the
wide sense used by Koltun including also most of the Subantarctic) are
endemic. Generic endemism is much less marked. Some 116 genera are
known in the Antarctic. Of these only nine (Koltun, 1970) can be considered to be endemic, Scolymastra, Acanthorhabdus, Hoplakithara,
Cercidochela, Meliidermu, Crellina, Bipocillopsis, Acanthoxa, and
Cladothenea.
Most of the Antarctic species of sponges belong to genera which are
well represented in the seas of the world, e.g. Mycale, Asbestopluma,
Myxilla, Tedania, Iophon, Hymedesmia, Isodictya, Anchinoe, Haliclona,
Adocia, and Hymeniacidon.
As in many other groups many sponges have a circum-Antarctic
distribution. The commonest species in this group are : Rossella antarctica Carter, R . racovitzae Topsent, Scolymastra joubini, Cinachyra
antarctica Carter, Tetilla leptodermu Sollas, Mycule tridens Hentschel,
M . acerata Kirkpatrick, Asbestopluma belgicae Topsent, Iophon radiatus
Topsent, I . spatulatus Kirkpatrick, Acanthorhabdus fragilis Burton,
Cercidochela lankesteri Kirkpatrick, Tedania masaa Ridley and Dendy,
T . oxeata Topsent, Axociella nidijcuta Kirkpatrick, Isodictya erinacea
Topsent, Ectyodoryx ramilobosa ( Topsent), Eurypon miniaceum Thiele
and Microxina benedeni (Topsent), (Koltun, 1964).
Koltun has shown that there are, however, marked differences
between the faunas of East and West Antarctica. McMurdo Sound in
the Ross Sea is the only area in Antarctica from which representatives
of Stelletta, Geodinella, Jmpis, Penares, Hemiasterella, Rhabderemia,
Chondropsis, and Dysidea have been collected (Burton, 1929). Other
species, e.g. Hoplakithara dendyi Kirkpatrick, Plocumia gaussiana
Hentschel, Clathria pauper Brondsted, Sphaerotylus schoenus Sollas,
Dolichancanthu macrodon Hentschel, Desmucella vestibularis Wilson
and Monoggringa longispinu von Lendenfeld have a wider distribution
but are still confined to Emt Antarctica.
Many fewer species are endemic to West Antarctica, e.g. Mycale
macrochela Burton, M . tylotornota Koltun, Isodactyla toxiphila Burton,
Myxilla australis Topsent, M . piatillaris Topsent, and Hymeniacidon