Pentapycnon

Pentapycnon is a genus of sea spiders (class Pycnogonida) in the family Pycnogonidae. As the name of this genus suggests, Pentapycnon is among the four genera of sea spiders with five pairs of legs in adults rather than the usual four leg pairs. This genus includes three species: P. bouvieri, P. charcoti, and P. geayi. The species P. bouvieri and P. charcoti are found in the Southern Ocean, whereas the species P. geayi is found in the Caribbean Sea, the tropical Atlantic Ocean, and the Mediterranean Sea. The species P. geayi is one of only two species of polymerous (i.e., extra-legged) sea spiders found outside the Southern Ocean.

== Discovery and taxonomy == This genus was proposed by the French zoologist Eugène Louis Bouvier in 1910 to contain the newly discovered species P. charcoti. In 1911, Bouvier described the second species in this genus, P. geayi. In 1993, A.F. Pushkin described the third species in this genus, P. bouvieri. In 1994, Christine Stiboy-Risch described P. magnum as a new species in this genus. In 1995, the American marine biologist C. Allan Child described another sea spider as a new species in this genus and also named this species P. bouvieri. Authorities now deem P. magnum to be a junior synonym of P. bouvier and consider the sea spiders described by Stiboy-Risch and Child to be the same species originally described by Pushkin.