38
R. K. DELL
torquata Topsent. Koltun (1970) does not believe that these differences
between East and West Antarctica can be accounted for solely by our
admittedly incomplete knowledge of the fauna.
The closest relationships of the Antarctic sponges appear to be with
the Falklands and southern South America. More than 50 species are
found in both areas, whereas only 30 species are common to the Antarctic
and Australasia.
Abyssal sponges of the southern oceans are as yet hardly known.
About 30 species have been recorded belonging t o such genera as
Caulophacus, Malacosaccus, Holascus, Aubcalyx, Hyalonema, Asbestopluma and Cladorhim.
One of the characteristic Antarctic sponge families is the Rossellidae.
It is a family of glass sponges, some members of which grow to great
size. Normally found below 100 m, members of this family are found
commonly on the shelf. It is the abundance of these forms in comparatively shallow water that gives a unique character to the
benthos of the Antarctic. Anyone who has sorted collections of
Antarctic benthic animals either straight from the trawls, or from bulk
preserved material in museum or laboratory on the other side of the
world, will know the long, unbelievably sharp, glassy spicules which
almost in themselves certify the collection as Antarctic.
Koltun (1969) has presented eight distribution maps showing patterns for selected Antarctic and Subantarctic sponges (Fig. 4). I n the
family Rossellidae, the genus Rossella is almost completely confined to
Antarctic and Subantarctic waters (the one exception being R. nodastrella Topsent, from off the Azores). Burton (1929) had reduced the
Antarctic species of Rossella to four, R. antarcticu, R. racovitzae, R.
nuda Topsent, and R. villosa Burton (a course with which Koltun
concurs). All four of these species are circumpolar, along with the two
other characteristic members of the subfamily Rossellinae, Scolymastra
joubini and Anoxyculyx i j i m e Kirkpatrick. Scolymastra joubini
reaches a height of 100 cm or more.
The group of the Tetractinellida has 19 species in the Antarctic.
The most widely distributed and most characteristic of these are:
Monosyringa longispina (Lendenfeld), Tetilla leptoderma SoUas, Cinachyra antarcticu Carter, C . barbata Sollas, and Plakina trilopha Schulze.
About 25 species of the Clavaxinellida occur in the Antarctic,
mostly belonging to the genera ~atrunculia, St~lacordyla, Xuberites,
Polymastia, Sphaerotylus, Axinetla and Rhizaxinella. This group
includes the main group of bipolar sponges and the level of endemics is
comparatively low (35%).
About 50 species of the wide ranging group of Haplosclerida occur,
R. K. DELL
torquata Topsent. Koltun (1970) does not believe that these differences
between East and West Antarctica can be accounted for solely by our
admittedly incomplete knowledge of the fauna.
The closest relationships of the Antarctic sponges appear to be with
the Falklands and southern South America. More than 50 species are
found in both areas, whereas only 30 species are common to the Antarctic
and Australasia.
Abyssal sponges of the southern oceans are as yet hardly known.
About 30 species have been recorded belonging t o such genera as
Caulophacus, Malacosaccus, Holascus, Aubcalyx, Hyalonema, Asbestopluma and Cladorhim.
One of the characteristic Antarctic sponge families is the Rossellidae.
It is a family of glass sponges, some members of which grow to great
size. Normally found below 100 m, members of this family are found
commonly on the shelf. It is the abundance of these forms in comparatively shallow water that gives a unique character to the
benthos of the Antarctic. Anyone who has sorted collections of
Antarctic benthic animals either straight from the trawls, or from bulk
preserved material in museum or laboratory on the other side of the
world, will know the long, unbelievably sharp, glassy spicules which
almost in themselves certify the collection as Antarctic.
Koltun (1969) has presented eight distribution maps showing patterns for selected Antarctic and Subantarctic sponges (Fig. 4). I n the
family Rossellidae, the genus Rossella is almost completely confined to
Antarctic and Subantarctic waters (the one exception being R. nodastrella Topsent, from off the Azores). Burton (1929) had reduced the
Antarctic species of Rossella to four, R. antarcticu, R. racovitzae, R.
nuda Topsent, and R. villosa Burton (a course with which Koltun
concurs). All four of these species are circumpolar, along with the two
other characteristic members of the subfamily Rossellinae, Scolymastra
joubini and Anoxyculyx i j i m e Kirkpatrick. Scolymastra joubini
reaches a height of 100 cm or more.
The group of the Tetractinellida has 19 species in the Antarctic.
The most widely distributed and most characteristic of these are:
Monosyringa longispina (Lendenfeld), Tetilla leptoderma SoUas, Cinachyra antarcticu Carter, C . barbata Sollas, and Plakina trilopha Schulze.
About 25 species of the Clavaxinellida occur in the Antarctic,
mostly belonging to the genera ~atrunculia, St~lacordyla, Xuberites,
Polymastia, Sphaerotylus, Axinetla and Rhizaxinella. This group
includes the main group of bipolar sponges and the level of endemics is
comparatively low (35%).
About 50 species of the wide ranging group of Haplosclerida occur,