''Porpita prunella'' is a marine species of

hydrozoa Hydrozoa (hydrozoans; ) are a taxonomic class of individually very small, predatory animals, some solitary and some colonial, most of which inhabit saline water. The colonies of the colonial species can be large, and in some cases the specializ ...

n organisms within the family Porpitidae. It consists of colonies of

zooids A zooid or zoöid is a single animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooi ...

. Very little is known about this species, as there have been no confirmed sightings since its discovery in 1801 and naming by

Haeckel Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist and artist. He discovered, described and named thousands of new sp ...

in 1888. Being in the chondrophore group, it is likely that its behaviour is similar to the other species of the genera in the family. However there are also serious doubts as to its very existence as a separate species and may in fact be a synonym for ''Porpita porpita'' instead.

Description and characteristics

The sole reported observation of a member of the species was by

in 1888. He had mistakenly placed several illustrations of the species from different views and stages of its life cycle on ''siphonophorae'', as the chondrophores were originally placed along with the

Siphonophores Siphonophorae (from Greek ''siphōn'' 'tube' + ''pherein'' 'to bear') is an order within Hydrozoa, which is a class of marine organisms within the phylum Cnidaria. According to the World Register of Marine Species, the order contains 175 specie ...

. However simple conclusions about the species can be made from these illustrations and the relationship between the other members of

Porpitidae The chondrophores or porpitids are a small group of hydrozoans in the family Porpitidae. Though it derives from an outdated name for this lineage (see below), some still find the term "chondrophore" useful as a synonym to "porpitid" in discussion ...

, as all of the chondrophores have features common to all species. All chondrophores possess small tentacles that are known to cause minor irritation to human skin. They live at the surface of the open ocean, and are colonies of carnivorous, free-floating hydroids whose role in the plankton community is similar to that of pelagic

jellyfish Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...

. The structures that cause their buoyancy – ''floats'' – are gas-filled membranes in other chondrophores. The floats are not obvious in this species from Haeckel's description, and have not been formally described, although the strange hat-like structure on the hydrozoan's aboral side may have this function. The hydroid colony itself closely resembles the tentacles of a

scyphozoa The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). The class name Scyphozoa comes from the Greek word ''skyphos'' (), denoting a kind of drinking cup and alluding to the ...

n; however, each tentacle structure is an individual zooid, which may consist of a

medusa In Greek mythology, Medusa (; Ancient Greek: Μέδουσα "guardian, protectress"), also called Gorgo, was one of the three monstrous Gorgons, generally described as winged human females with living venomous snakes in place of hair. Those ...

or a polyp. Each strand consists of numerous branchlets, which all end in stinging

nematocysts A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this c ...

. The species is considered to be

neuston Neuston, also known as pleuston, are organisms that live at the surface of the ocean or an estuary, or at the surface of a lake, river or pond. Neuston can live on top of the water surface or may be attached to the underside of the water surface. ...

ic, passively drifting on the surface of the sea. A single mouth is located on its underside, and it appears to be re-orientable and movable. The mouth is used for both the intake of prey and the expulsion of wastes.

References

{{Taxonbar, from=Q2196930 Porpitidae Animals described in 1888 Taxa named by Ernst Haeckel