Potamilla antarctica (Kinberg 1866)

Genus Potamilla Malmgren, 1866
Potamilla antarctica (Kinberg, 1867)
Plate XLI, figs. 10-12

Laonome antarctica Kinberg, 1867, p. 354. Rada York, Strait of Magellan.

Ehlers, 1897, p. 135. South Georgia and Strait of Magellan, in 2-12 fms.

Ehlers, 1900a, p. 17. Strait of Magellan.

Ehlers, 1901, p. 216. Strait of Magellan.

Ehlers, 1912, p. 29. Cape Armitage, Ross Island; in 100-180 fms.

Potamilla antarctica Gravier, 1907, pp. 59-62, figs. 38-43. Booth Island, Biscoe Bay.

Gravier, 1911a, p. 144. Marguerite Bay, Port Lock­roy, Peltier Channel, in 70-254 m.

Ehlers, 1913, pp. 575-576. Baie de l'Observatoire, Kerguelen Islands; Wilhelm II Coast; in 385 m.

Pixell, 1913, pp. 355-356. Tussac Island (TussockIsland) and Cape Pembroke, Falkland Islands,shore.

Fauvel, 1916, p. 474. Falkland Islands, at low tide.

Benham, 1921, p. 109. Macquarie Island and Boat Harbor, Adelie Coast, in 25 to 157 fms.

Monro, 1930, pp. 199-201. South Georgia and Falkland Islands, in 1 to 391 m.

Benham, 1927, p. 143. McMurdo Sound, Oates Coast, Cape Adare, and Granite Harbor, in 45 to 250 fms.

Augener, 1932b, p. 68. Bouvet Island, South Georgia; Princess Martha Coast; Elephant and Adelaide islands; in 50 to 620 m.

Fauvel, 1936, p. 37. Strait of Magellan.

Monro, 1936, p. 188. Many stations in Antarctic seas.

Monro, 1939, pp. 148-149. Macquarie Island, Mac. Robertson Land, and Adelie Coast, in 17 to 640 m. Fauvel, 1941, p. 295. Patagonia.

Fauvel, 1951, p. 770. Adelie Coast, in 10 to 60 m.

Hartman, 1952, p. 236. Ross Island, MargueriteBay, and Knox Coast, in 35 to 110 fms.

Hartman, 1953, p. 53. Numerous stations in Ant‑arctic regions.

Diagnosis : Length of larger specimens 42.5 to 92 mm, of which tentacular crown is 22 mm; smaller ones 26 to 35 mm and width 2 to 3.5 mm. Segments include 8 thoracic and to 58 abdominal setigers. Ten­tacular crown uncolored and without eyes on bran­chial base, thoracic dorsum and thoracic tori brown or speckled, and branchiae transversely brown-barred. In life the ventral shields flesh-colored to orange, and branchiae gray with white and brown bands. Radioles number about 15 pairs of long and 3 pairs of shorter ventral groups; tip of each bare. Thoracic notopodia with limbate and spatulate (fig. 10) setae; neuropodia with avicular hooks (fig. 12) and pick-axe setae (fig. 11). Abdominal notopodia with avicular hooks and neuropodia with limbate setae. Tubes horny brown, irregularly spiraled, or adorned with horny spines [Monro, 1939, p. 149]. Incubates eggs inside bran­chial crown. Considered a common, variable species.

Distribution: Southern South America to mainland of Antarctica; in shore to moderate depths.

(Hartman 1966)