Haliclystus antarcticus

Haliclystus antarcticus attached to rock surface.

Two Haliclystus antarcticus specimens attached to the rock and red algae thallus. Scale bar – 1.2 cm.

Haliclystus antarcticus Pfeffer 1889 is a species of Stauromedusae from Antarctic waters.

Morphology, habits and life cycle

On King George Island commonly found on summer periods over red algae and rocks exposed during low tides. Stauromedusae ranging from 3.5-16.2 mm height. Conical calyx clearly distinct from stalk. Eight arms, each with 6-224 capitate tentacles. Living specimens red-orange or green, depending on the substrate. Anchors present. Stalk four-chambered. Specimens from Antarctic Peninsula islands, south Chile and Argentina are considered the same species. Molecular data related the species with an inconspicuous small cnidarian formerly assigned to the class Hydrozoa (Microhydrula limopsicola).

References

• Carlgren, O. 1930. Die Lucernariden. Further Zoological Results of the Swedish Antarctic Expedition 1901-1903 2: 1-18.
• Miranda, L.S., A.G. Collins, & A.C. Marques. 2010. Molecules clarify a cnidarian life cycle – The "hydrozoan" Microhydrula limopsicola is an early life stage of the staurozoan Haliclystus antarcticus. PLoS one 5: e10182.
• Miranda, L.S., A.C. Morandini, & A.C. Marques. 2009. Taxonomic review of Haliclystus antarcticus Pfeffer, 1889 (Stauromedusae, Staurozoa, Cnidaria), with remarks on the genus Haliclystus Clark, 1863. Polar Biology 32: 1507-1519.
• Pfeffer, G. 1889. Zur Fauna der Süd-Georgien. Jahrbuch der Hamburgischen Wissenschaftlichen Anstalten 6: 37-55.