ANTARCTIC BENTHOS
83
1. Amphineura
Antarctic chitons have also often been treated in general works on
Mollusca but the following papers refer to this group alone: Thiele
(1906,1908,1911), E. A. Smith (1907),Vayssibre (1916), Odhner (1923a),
Bergenhayn (1937), Cotton (1937), Castellanos (1959) and A. G. Smith
(1961).
Aplacophora seem to be not uncommon in Antarctic seas. A few
reports have appeared on the group, e.g. Nierstrasz (1908), Plate
(1908d) and Thiele (1913), but large collections still await treatment.
The shelf of the Antarctic continent excluding the Weddell Sea, the
Antarctic Peninsula and the Bellingshausen Sea, supports only five
chitons :
Lepidopleurus kerguelensis (Haddon) (0-1 080 m) ;
Lepidopleurus belgicae (Pelseneer) (500 m) ;
Callochiton gaussi Thiele (0-650 m) ;
C . steineni (Pfeffer) (2P300 m) ;
Nuttalochiton mirandus (Thiele) (135-640 m).
Of these Lepidopleurus belgicae has not been recognized since its original
description, but the other four are very wide ranging, almost certainly
cir cum -Antarctic.
The relationships of this small Antarctic chiton fauna are not difficult to trace. Lepidopleurus belgicae is uncertainly placed in this genus,
and cannot be discussed until its true position is known. Lepidopleurus
kerguelensis is widely distributed in the Subantarctic and is related to
a series of forms from the Magellan area, and in New Zealand. The
group to which the closely allied Callochiton gaussi and C . steineri
belong is also well represented in the Magellanic region, with other
species on the islands of the Scotia Arc, in the Subantarctic Islands, and
in New Zealand. Nuttalochiton mirandus (previously considered to
belong to the monotypic endemic Antarctic genus Notochiton) has allied
forms in the Magellanic region, one of which has also been recorded
from the Weddell Sea.
Another group of species has Subantarctic or Magellan distributions
or relationships, the individual members extending southwards to varying limits through the islands of the Scotia Arc. Hemiarthrun setulosum
Dall (well-known as a chiton which broods its young) is widely distributed in the Subantarctic and the Magellan area and extends through
South Georgia and the South Orkneys to the Antarctic Peninsula.
Tonicina zschaui (Pfeffer) extends from the Magellan area through
South Georgia and the South Shetlands to the Antarctic Peninsula.
83
1. Amphineura
Antarctic chitons have also often been treated in general works on
Mollusca but the following papers refer to this group alone: Thiele
(1906,1908,1911), E. A. Smith (1907),Vayssibre (1916), Odhner (1923a),
Bergenhayn (1937), Cotton (1937), Castellanos (1959) and A. G. Smith
(1961).
Aplacophora seem to be not uncommon in Antarctic seas. A few
reports have appeared on the group, e.g. Nierstrasz (1908), Plate
(1908d) and Thiele (1913), but large collections still await treatment.
The shelf of the Antarctic continent excluding the Weddell Sea, the
Antarctic Peninsula and the Bellingshausen Sea, supports only five
chitons :
Lepidopleurus kerguelensis (Haddon) (0-1 080 m) ;
Lepidopleurus belgicae (Pelseneer) (500 m) ;
Callochiton gaussi Thiele (0-650 m) ;
C . steineni (Pfeffer) (2P300 m) ;
Nuttalochiton mirandus (Thiele) (135-640 m).
Of these Lepidopleurus belgicae has not been recognized since its original
description, but the other four are very wide ranging, almost certainly
cir cum -Antarctic.
The relationships of this small Antarctic chiton fauna are not difficult to trace. Lepidopleurus belgicae is uncertainly placed in this genus,
and cannot be discussed until its true position is known. Lepidopleurus
kerguelensis is widely distributed in the Subantarctic and is related to
a series of forms from the Magellan area, and in New Zealand. The
group to which the closely allied Callochiton gaussi and C . steineri
belong is also well represented in the Magellanic region, with other
species on the islands of the Scotia Arc, in the Subantarctic Islands, and
in New Zealand. Nuttalochiton mirandus (previously considered to
belong to the monotypic endemic Antarctic genus Notochiton) has allied
forms in the Magellanic region, one of which has also been recorded
from the Weddell Sea.
Another group of species has Subantarctic or Magellan distributions
or relationships, the individual members extending southwards to varying limits through the islands of the Scotia Arc. Hemiarthrun setulosum
Dall (well-known as a chiton which broods its young) is widely distributed in the Subantarctic and the Magellan area and extends through
South Georgia and the South Orkneys to the Antarctic Peninsula.
Tonicina zschaui (Pfeffer) extends from the Magellan area through
South Georgia and the South Shetlands to the Antarctic Peninsula.