Colossendeis specimens are beautiful creatures highly admired in collections due to their larger size compared to other pycnogonid species. The bizarre morphology of pycnogonids is in full display in this genus in which most of the species have a proboscis longer than the trunk. Colossendeis australis is known as a circumpolar and eurybathic (15-3935 m) species and can be recognized by a unique combination of characters that include a downcurved swollen proboscis, subchelate oviger strigilis and short propodal claws. The biology of Colossendeidae in general is poorly known, there is no information about their reproductive biology as no eggs or larvae have ever been found. On the other hand this lineage of pycnogonids could be one of the most ancient according to the phylogeny proposed (Arango pers. comm.).
Child C.A. 1995. Antarctic and Subantarctic Pycnogonida: Nymphonidae, Colossendeidae, Rhynchothoraxidae, Pycnogonidae, Endeididae, and Callipallenidae. In: S.D. Cairns (Ed.) Biology of the Antarctic Seas XXIV. Antarctic Research Series 69, pp. 165..
Cano E. & López-González P.J. 1993. Colossendeis species (Pycnogonida: Colossendeidae) collected during Italica XIX cruise to Victoria Land (Antarctica), with remarks on some taxonomic characters of the ovigers. Scientia Marina 71, 661-681.
Although Colossendeis has representatives in all oceans around the world, the deep waters of the Southern Ocean appear as a centre of species radiation for these fascinating animals (Arango pers. comm.).
C. australis is present in a wide bathymetric range from 143 to 3931 m depth (Cano & López-González, 2007). It has a circumpolar distribution and some sites in the Southern Atlantic and Southern Pacific basins, and is found in the Falkland Islands, South Sandwich Islands, Orcadas Islands, South Giorgia, Kerguelen Islands, Antarctic Peninsula, Ross Sea, Adelie Coast and off the coast of Chile and Argentina (Child, 1995).