ANTARCTIC BENTHOS
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of species. The family Cerithiidae elsewhere has species ranging in size
from several inches down to a few millimetres. The Antarctic species
are all small, belonging to the genera Cerithiella, Cerithiopsilla and
Eumetula.
The family Trichotropidae is largely a family of cold and temperate
waters. Within the restricted Antarctic region four endemic genera
occur embracing seven species. The family Naticidae has adapted itself
well to Antarctic conditions. The genus Amauropsis with a thick brown
FIG. 11. Speciation within the buccinid genus Chlanidota.
protective epidermis has ten species in the Antarctic and Subantarctic.
Amauropsis (Kerguelenatica) grisea (Martens) is circum-Antarctic and
also occurs in South Georgia, and Kerguelen. Sinuber has two subspecies occurring around the continent and along the Scotia Arc, with
a second species at Kerguelen. The genus Prolacuna is endemic to the
Antarctic with four species. The monotypic endemic genus Frowina is
known from the Davis Sea, while Tectonatica has two subspecies ranging
from Magellan Strait to Paulet Island, on the Antarctic Peninsula.