A new genus and species of sea pen (Octocorallia : Pennatulacea : Stachyptilidae) from the Antarctic Peninsula

Abstract

Only six of the thirty-three valid genera of sea pens have previously been recorded from the Southern Oceans (Subantarctic and Antarctic regions). The discovery of a new genus, Gilibelemnon, and new species, Gilibelemnon octodentatum, of stachyptilid sea pen is here reported from the South Shetland Islands, which makes a total of eight genera known to occur in the Southern Oceans and thirty-four genera of sea pens known worldwide. Diagnostic features of the new genus are described, including the presence of a clearly delimited dorsal and ventral naked track on the rachis, the calyces with eight long terminal teeth, the siphonozooids densely and irregularly distributed and the presence of three-flanged rods in the peduncle surface. A discussion of sea pen phylogeny and biogeography in the Antarctic region is also provided.