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Opisthobranch
Opisthobranchs () is now an informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping. Euopisthobranchia is a taxon containing a revised collection of opisthobranchs, and that taxon is considered monophyletic. Euopisthobranchia does not include some "traditional" opisthobranchs such as the Sacoglossa and the Acochlidiacea. The subclass Heterobranchia now contains all the species which used to be assigned to Opisthobranchia, plus all the species in the Pulmonata. The subclass Opisthobranchia included species in the order Cephalaspidea (bubble shells and headshield slugs), the sacoglossans, anaspidean sea hares, pelagic sea angels, sea butterflies, and many families of the Nudibranchia. ''Opisthobranch'' means "gills behind" (and to the right) of the heart. In contrast, ''Prosobranch'' means ''gills in front'' (of the heart). Opist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acochlidiacea
Acochlidiacea, common name acochlidians, are a taxonomic clade of very unusual sea snails and sea and freshwater slugs, aquatic gastropod mollusks within the large clade Heterobranchia. Acochlidia is a variant spelling. Description These are mostly very small animals, without a shell or gills, distinguished by the visceral mass being sharply set off from the rest of the body. Being a small group with only 30 species worldwide known in 2010, and 32 species described in 2011, and 33 in 2012 (+9 undescribed ''Pontohedyle'' species), these slugs are morphologically and biologically highly aberrant and diverse, comprising a series of unusual characters (e.g. secondary gonochorism, lack of copulatory organs, asymmetric radulae). Most acochlidians live interstitially in marine sands, while some have conquered limnic systems (uniquely within opisthobranch gastropods). Taxonomy Nils Hjalmar Odhner established this taxon as a family in 1937, when he created the families Microhedylid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacoglossa
Sacoglossa, commonly known as the sacoglossans or the "solar-powered sea slugs", are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia. Sacoglossans live by ingesting the cellular contents of algae, hence they are sometimes called "sap-sucking sea slugs". Some sacoglossans simply digest the fluid which they suck from the algae, but in some other species, the slugs sequester and use within their own tissues living chloroplasts from the algae they eat, a very unusual phenomenon known as kleptoplasty, for the "stolen" plastids. This earns them the title of the "solar-powered sea slugs", and makes them unique among metazoan organisms, for otherwise kleptoplasty is known only among single-celled protists. The Sacoglossa are divided into two clades - the shelled families (Oxynoacea) and the shell-less families (Plakobranchacea). The four families of shelled species are: Cylindrobullidae, Volvatellidae, Oxynoidae, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacoglossa
Sacoglossa, commonly known as the sacoglossans or the "solar-powered sea slugs", are a superorder of small sea slugs and sea snails, marine gastropod mollusks that belong to the clade Heterobranchia. Sacoglossans live by ingesting the cellular contents of algae, hence they are sometimes called "sap-sucking sea slugs". Some sacoglossans simply digest the fluid which they suck from the algae, but in some other species, the slugs sequester and use within their own tissues living chloroplasts from the algae they eat, a very unusual phenomenon known as kleptoplasty, for the "stolen" plastids. This earns them the title of the "solar-powered sea slugs", and makes them unique among metazoan organisms, for otherwise kleptoplasty is known only among single-celled protists. The Sacoglossa are divided into two clades - the shelled families (Oxynoacea) and the shell-less families (Plakobranchacea). The four families of shelled species are: Cylindrobullidae, Volvatellidae, Oxynoidae, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosomata
Sea angels ( clade Gymnosomata) are a large group of small free-swimming sea slugs, not to be confused with Cnidarians (Jellyfish and other similar creatures), classified into six different families. They are pelagic opisthobranchs in the clade Gymnosomata within the larger mollusc clade Heterobranchia. Sea angels were previously referred to as a type of pteropod. Sea angels are also sometimes known as "cliones" but this is potentially misleading because the family Clionidae is just one of the families within this clade. Recent molecular data suggest the Gymnosomata form a sister group to the Thecosomata (other planktonic, weakly or nonmineralized gastropods), but this long-standing hypothesis has also had some recent detractors. Fossils of the group go back to the Middle Frasnian stage of the Late Devonian period. Distribution These organisms have a wide geographic range, from polar regions, under sea ice, to equatorial (tropic) seas. Description In this clade, the foo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Angels
Sea angels (clade Gymnosomata) are a large group of small free-swimming sea slugs, not to be confused with Cnidarians (Jellyfish and other similar creatures), classified into six different families. They are pelagic opisthobranchs in the clade Gymnosomata within the larger mollusc clade Heterobranchia. Sea angels were previously referred to as a type of pteropod. Sea angels are also sometimes known as "cliones" but this is potentially misleading because the family Clionidae is just one of the families within this clade. Recent molecular data suggest the Gymnosomata form a sister group to the Thecosomata (other planktonic, weakly or nonmineralized gastropods), but this long-standing hypothesis has also had some recent detractors. Fossils of the group go back to the Middle Frasnian stage of the Late Devonian period. Distribution These organisms have a wide geographic range, from polar regions, under sea ice, to equatorial (tropic) seas. Description In this clade, the foot of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterobranchia
Heterobranchia, the ''heterobranchs'' (meaning "different-gilled snails"), is a taxonomic clade of snails and slugs, which includes marine, aquatic and terrestrial gastropod mollusks. Heterobranchia is one of the main clades of gastropods. Currently Heterobranchia comprises three informal groups: the lower heterobranchs, the opisthobranchs and the pulmonates.Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005. ''Classification and nomenclator of gastropod families''. Malacologia: International Journal of Malacology, 47(1-2). ConchBooks: Hackenheim, Germany. . . 397 pp. http://www.vliz.be/Vmdcdata/imis2/ref.php?refid=78278 Diversity The three subdivisions of this large clade are quite diverse: * The Lower Heterobranchia includes shelled marine and freshwater species. * Opisthobranchia are almost all marine species, some shelled and some not. The internal organs of the opisthobranchs have undergone detorsion (unwinding of the visc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylindrobullida
''Cylindrobulla'' is a genus of sea snails or bubble snails, marine gastropod mollusks in the clade Sacoglossa. ''Cylindrobulla'' is the type genus of the family Cylindrobullidae and it is the only genus in the family. Taxonomy The suborder Cylindrobulloidea used to be recognized as monogeneric suborder; in other words there was only one family in the suborder, the family Cylindrobullidae, and only one genus ''Cylindrobulla''. 1996 taxonomy It was treated by Jensen (1996) as a sister group of Sacoglossa and placed it in the new order Cylindrobullacea. 1998 taxonomy Mikkelsen (1998) has argued that the genus ''Cylindrobulla'' actually belongs in Oxynoacea within shelled Sacoglossa. This change in taxonomy was suggested on the basis of the similarity in many characteristics: digestive, sexual, pallial (= concerning the mantle), and the nervous system. 2005 taxonomy According to the taxonomy by Bouchet & Rocroi (2005), is the Cylindrobullidae the only family in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. There are many thousands of species of sea snails and slugs, as well as freshwater snails, freshwater limpets, and land snails and slugs. The class Gastropoda contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Late Cambrian. , 721 families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently extant with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mollusca, and are the most highly diversified class in the phylum, with 65,000 to 80,000 living snail and slug species. The anatomy, behavior, feeding, and re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thecosomata
Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified shell, although it is often very light and / or transparent. The sea butterflies include some of the world's most abundant gastropod species, and because of their large numbers are an essential part of the food chain, and a significant contributor to the oceanic carbon cycle. The sea butterflies are included in the Pteropoda order, and are also included in the informal group Opisthobranchia. Morphology Sea butterflies float and swim freely in the water, and are carried along with the currents. This has led to a number of adaptations in their bodies. The shell and the gill have disappeared in several families. Their gastropodal foot has taken the form of two wing-like lobes, or ''parapodia'', which propel the animal through the sea by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplysiomorpha
The clade Anaspidea, commonly known as sea hares (''Aplysia'' species and related genera), are medium-sized to very large opisthobranch gastropod molluscs with a soft internal shell made of protein. These are marine gastropod molluscs in the superfamilies Aplysioidea and Akeroidea. The common name "sea hare" is a direct translation from la, lepus marinus, as the animal's existence was known in Roman times. The name derives from their rounded shape and from the two long rhinophores that project upward from their heads and that somewhat resemble the ears of a hare. Taxonomy Many older textbooks and websites refer to this suborder as "Anaspidea". The original author Paul Henri Fischer described the taxon Anaspidea at unspecified rank above family. In 1925 Johannes Thiele established the taxon Anaspidea as a suborder. 2005 taxonomy Since the taxon Anaspidea was not based on an existing genus, this name is no longer available according to the rules of the ICZN. Anaspidea ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbraculida
Umbraculoidea is a superfamily of unusual false limpets with a thin soft patelliform shell, marine gastropod molluscs in the clade Umbraculida, within the clade Euopisthobranchia. There are two families in this superfamily, which is listed as the only superfamily in the clade Umbraculida within the informal group Opisthobranchia in the taxonomy of Bouchet & Rocroi (2005). Taxonomy A study by Grande ''et al.'', published in 2004, concluded that Umbraculoidea was a sister clade to the Cephalaspidea (Acteonoidea excluded). 2005 taxonomy Umbraculoidea contains two families: *Family Umbraculidae *Family Tylodinidae Tylodinidae is a family of sea snails or false limpets, marine opisthobranch gastropod mollusks in the superfamily Umbraculoidea. Taxonomy 2005 taxonomy The family Tylodinidae consists of the following subfamilies (according to the taxonom ... 2010 taxonomy Jörger et al. (2010) moved Umbraculoidea to the Euopisthobranchia. Footnotes External links ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Butterflies
Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified shell, although it is often very light and / or transparent. The sea butterflies include some of the world's most abundant gastropod species, and because of their large numbers are an essential part of the food chain, and a significant contributor to the oceanic carbon cycle. The sea butterflies are included in the Pteropoda order, and are also included in the informal group Opisthobranchia. Morphology Sea butterflies float and swim freely in the water, and are carried along with the currents. This has led to a number of adaptations in their bodies. The shell and the gill have disappeared in several families. Their gastropodal foot has taken the form of two wing-like lobes, or ''parapodia'', which propel the animal through the sea by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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