? Sea angel
Clione limacina
Scientific classification
Kingdom: Animalia Phylum: Mollusca Class: Gastropoda Subclass: Orthogastropoda Superorder: Heterobranchia Order: Opisthobranchia Suborder: Gymnosomata
Families
Clionidae Cliopsidae Hermaeidae Hydromylidae Laginiopsidae Notobranchaeidae Pneumodermatidae Thliptodontidae

Sea angels are small pteropod mollusks of the suborder Gymnosomata. Their feet have developed into wing-like appendages (parapodia) and their shells have been lost, both adaptations made to suit their free-swimming oceanic lives. These adaptations also explain the common name sea angel and the New Latin name of the order; from gymnos meaning "naked" and soma meaning "body." Within the order are approximately eight families and 17 genera. Sea angel (Clione limacina) from NOAA Photo Library. ... Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Subregnum Bilateria  Acoelomorpha  Orthonectida  Rhombozoa  Myxozoa  Superphylum Deuterostomia     Chordata (vertebrates, etc. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Subclass Subclass Eogastropoda     Patellogastropoda Subclass Orthogastropoda   Superorder Cocculiniformia   Superorder Hot Vent Taxa     Neomphaolida   Superorder Vetigastropoda   Superorder Neritaemorphi     Neritopsina   Superorder Caenogastropoda     Architaenioglossa     Sorbeoconcha   Superorder Heterobranchia     Heterostropha     Opisthobranchia     Pulmonata The gastropods, or univalves, are the largest and most successful class of mollusks, with 60,000-75,000 extant species known, comprising the... Superorders Cocculiniformia Hot Vent taxa Vetigastropoda Neritaemorphi Caenogastropoda Heterobranchia In their work, which has become a standard reference in the field, Ponder and Lindberg (1997) showed that the Orthogastropoda is one of two subclasses of the Gastropoda the class of molluscs, the other subclass being the Eogastropoda. ... Orders Heterostropha Opisthobranchia Pulmonata This article does not cite its references or sources. ... Suborders Cephalaspidea Sacoglossa Anaspidea Notaspidea Thecosomata Gymnosomata Nudibranchia   Infraorder Anthobranchia   Infraorder Cladobranchia For information on the anti-aircraft weapons system, see Sea Slug missile In zoology, the Opisthobranchia (Milne Edwards, 1848) (also known as opisthobranchs) used to be a subclass of gastropods, within the phylum Mollusca, but they are now... Genera Clione Clionina Fowlerina Paedoclione Paraclione Thalassopterus The sea angels of the family Clionidae (Rafinesque, 1815) are gelatinous, mostly transparent pteropods. ... Genera Cliopsis Pruvotella As all gymnosome pteropods, the sea angels of the family Cliopsidae (Costa, 1873) lack a shell (unless in early embryonic stage). ... Genus Hydromyles The small pelagic snails of the family Hydromylidae (Pruvot-Fol, 1942) lack a shell (except in their early embryonic stage). ... Genus Laginiopsis The small pelagic snails of the family Laginiopsidae (Pruvot-Fol, 1922) lack a shell (except in their early embryonic stage). ... Genera Notobranchaea The small pelagic snails of the family Notobranchaeidae (Pelseneer, 1886) lack a shell (except in early embryonic stage). ... Genera Pneumoderma Pneumodermopsis Schizobrachium Spongiobranchaea Abranchaea Platybrachium The small pelagic snails of the family Pneumodermatidae (Latreille, 1825) lack a shell (except in their early embryonic stage). ... Genera Thliptodon Cephalobrachia Massya The small planktonic pelagic snails of the family Thliptodontidae (Kwietniewski, 1910) lack a shell (except in their early embryonic stage). ... Families Limacinidae Cavoliniidae Clioidae Creseidae Cuvierinidae Praecuvierinidae Peraclididae Cymbuliidae Desmopteridae Sea butterflies, or flapping snails, are holoplanktonic mollusks (Mollusca, Gasteropoda), belonging to the suborder Thecosomata (Blainville, 1824). ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... New Latin (or Neo-Latin) is a post-medieval version of Latin, now used primarily in International Scientific Vocabulary cladistics and systematics. ...

Also known as gymnosomes, sea angels belong to the Orthogastropoda a subclass of Gastropoda (snails and slugs) which includes nudibranchs. The other suborder of pteropods, Thecosomata, are superficially similar but not closely related. They have larger, broader parapodia, most species retaining a shell, and are known commonly as sea butterflies. Superorders Cocculiniformia Hot Vent taxa Vetigastropoda Neritaemorphi Caenogastropoda Heterobranchia In their work, which has become a standard reference in the field, Ponder and Lindberg (1997) showed that the Orthogastropoda is one of two subclasses of the Gastropoda the class of molluscs, the other subclass being the Eogastropoda. ... Subclass Subclass Eogastropoda     Patellogastropoda Subclass Orthogastropoda   Superorder Cocculiniformia   Superorder Hot Vent Taxa     Neomphaolida   Superorder Vetigastropoda   Superorder Neritaemorphi     Neritopsina   Superorder Caenogastropoda     Architaenioglossa     Sorbeoconcha   Superorder Heterobranchia     Heterostropha     Opisthobranchia     Pulmonata The gastropods, or univalves, are the largest and most successful class of mollusks, with 60,000-75,000 extant species known, comprising the... Infraorders See text Nudibranchs (Nudibranchia), form the largest suborder of the order Opisthobranchia, subclass Orthogastropoda, class Gastropoda in the phylum Mollusca. ... Families Limacinidae Cavoliniidae Clioidae Creseidae Cuvierinidae Praecuvierinidae Peraclididae Cymbuliidae Desmopteridae Sea butterflies, or flapping snails, are holoplanktonic mollusks (Mollusca, Gasteropoda), belonging to the suborder Thecosomata (Blainville, 1824). ...

Sea angels are gelatinous, mostly transparent and very small, with the largest species (Clione limacina) reaching 5 cm. Clione limacina is a polar species; those found in warmer waters are far smaller. Some species of sea angel feed exclusively on sea butterflies; the angels have terminal mouths with the radula common to mollusks, and tentacles to grasp their prey, sometimes with suckers similar to cephalopods. Their "wings" allow sea angels to swim much faster than the larger (usually fused) wings of sea butterflies. Other species of sea angel feed mostly on zooplankton. Radula is the scientific name for the toothed chitinous ribbon in the mouth of gastropods. ... Orders Sepiida Sepiolida Spirulida Teuthida Octopoda Vampyromorphida Nautilida The Cephalopods (head-foot) are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of arms or tentacles. ... Photomontage of plankton organisms Plankton is the aggregate community of weakly swimming but mostly drifting small organisms that inhabit the water column of the ocean, seas, and bodies of freshwater. ...

Another large polar species of sea angel, Clione antarctica, defends itself from predators by synthesizing a previously unknown molecule, named pteroenone. As predators will not eat the sea angel some animals, such as amphipods, take up home inside them. Local population density of Clione antarctica may reach claustrophobic levels; up to 300 animals per cubic metre have been recorded. Families about 200 partial list Alpheidae Ampeliscidae Amphilochidae Ampithoidae Anisogammaridae Aoridae Artesiidae Bogideillidae Bosminidae Caprellidae Corophiidae Crangonyctidae Eusiridae Gammaridae Hadziidae Haustoriidae Iphimediidae Ischyroceridae Leucothoidae Liljeborgiidae Lysianassidae Melitidae Phoxocephalidae Sebidae Talitridae Amphipoda (amphipods) include about 4600 different species of small, shrimp_like crustaceans. ...

Slowly beating their parapodia, sea angels gracefully fly through the upper 20 metres of the water column. Although usually slow-moving, they are capable of surprising bursts of speed. The animals are simultaneous hermaphrodites, fertilization occurring internally. A gelatinous egg mass is released during spawning, the eggs floating freely until hatching. Their embryonic shells are lost within the first few days after hatching. The 1st-century BC sculpture The Reclining Hermaphrodite, in the Museo Palazzo Massimo Alle Terme in Rome In zoology, a hermaphrodite is an organism of a species whose members possess both male and female sexual organs during their lives. ...