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Euopisthobranchia
Euopisthobranchia is a taxonomic clade of snails and slugs in the clade Heterobranchia within the clade Euthyneura. This clade was established as a new taxon by Jörger et al. in October 2010. Euopisthobranchia is a monophyletic portion of the Opisthobranchia as that taxon was traditionally defined but is not a replacement name for that group as several marine opisthobranch orders including Nudibranchia, Sacoglossa and Acochlidiacea are not included. Euopisthobranchia consist of the following taxa: * Umbraculoidea * Anaspidea * Runcinacea * Pteropoda * Cephalaspidea s.s. Gizzard Previous studies discussed the gizzard (i.e. a muscular oesophageal crop lined with cuticula) with gizzard plates as homologous apomorphic structures supporting a clade composed of Cephalaspidea s.s., Pteropoda and Anaspidea. A gizzard with gizzard plates probably originated in herbivorous taxa in which it worked like a grinding mill, thus might be secondarily reduced in carnivorous groups ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euthyneura
Euthyneura is a taxonomic infraclass of snails and slugs, which includes species exclusively from marine, aquatic and terrestrial gastropod mollusks in the clade Heterobranchia. Euthyneura are characterised by several autapomorphies, but are named for euthyneury. They are considered to be the most successful and diverse group of Gastropoda. Within this taxon, the Gastropoda have reached their peak in species richness and ecological diversity. This obvious evolutionary success can probably be attributed to several factors. Marine Opisthobranchia, e.g., have evolved several clades specialised on less used food resources such as sponges or cnidarians. A key innovation in the evolution of Pulmonata was the colonization of freshwater and terrestrial habitats.Klussmann-Kolb A., Dinapoli A., Kuhn K., Streit B. & Albrecht C. (2008). "From sea to land and beyond – New insights into the evolution of euthyneuran Gastropoda (Mollusca)". ''BMC Evolutionary Biology'' 2008, 8: 57. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterobranchia
Heterobranchia, the heterobranchs (meaning "different gill"), is a taxonomic clade of snails and slugs, which includes marine, aquatic, and terrestrial gastropod molluscs. Heterobranchia is one of the main clades of gastropods. Currently Heterobranchia comprises two groups: the opisthobranchs, and the pulmonates. Diversity The two subdivisions of this large clade are quite diverse: * Opisthobranchia are virtually all marine species, some shelled and some not, and comprise about 25 families and 2000 species of the bubble shells, the seaslugs, as well as the sea hares. The internal organs of the opisthobranchs have undergone detorsion (unwinding of the viscera that were twisted during torsion). * The Pulmonata comprises about 20000 species, includes the majority of land snails and slugs, many freshwater snails, and a small number of marine species. The mantle cavity of the Pulmonata is modified into an air-breathing organ. They are also characterized by detorsion a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbraculoidea
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 Acteonoidea is a superfamily of sea snails, or bubble snails, marine gastropod mollusks. Taxonomy In the taxonomy of Bouchet & Rocroi (2005), the superfamily Acteonoidea has been included into the informal group "Lower Heterobranchia" (He ... excluded). 2005 taxonomy Umbraculoidea contains two families: *Family Umbraculidae *Family Tylodinidae 2010 taxonomy Jörger et al. (2010) moved Umbraculoidea to the Euopisthobranchia. References External links w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalaspidea
The order Cephalaspidea, also known as the headshield slugs and bubble snails, is a major taxon of sea slugs and bubble snails, marine (ocean), marine gastropod mollusks within the larger clade Euopisthobranchia. Bubble shells is another common name for these families of marine gastropods, some of which have thin bubble-like shells. This clade contains more than 600 species. Members of this worldwide clade used to be considered the most ancestral of the opisthobranchs, but now they are considered as derived and specialized members of the Euthyneura Spengel, 1881. Headshield slugs are the most morphologically diverse group of all the opisthobranchs. Anatomy The vast majority possess a shell, although it may be reduced or internal. They have a well-developed headshield, a characteristic broadening at the head, which is used to plow beneath the surface of the sand. This headshield prevents the sand entering the mantle cavity. There is a muscular foot with or without parapodia (f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runcinacea
Runcinoidea is a taxonomic superfamily (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005) or a clade Runcinaecea (according to the Malaquias et al. (2009)) of sea slugs, marine gastropod mollusks in the order RuncinidaJörger K. M., Stöger I., Kano Y., Fukuda H., Knebelsberger T. & Schrödl M. (2010). "On the origin of Acochlidia and other enigmatic euthyneuran gastropods, with implications for the systematics of Heterobranchia". ''BMC Evolutionary Biology'' 10: 323. .MolluscaBase eds. (2021). MolluscaBase. Runcinoidea H. Adams & A. Adams, 1854. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=411898 on 2021-04-12 Taxonomy 2005 taxonomy Runcinoidea was recognized as a superfamily in the clade Cephalaspidea, within the informal group Opisthobranchia in the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). They also recognized two families, Runcinidae and Ilbiidae. 2009 taxonomy Mal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnosomata
Sea angels (clade Gymnosomata) are a large group of small free-swimming sea slugs, classified into six separate families. They are pelagic opisthobranchs in the clade Gymnosomata within the larger mollusc clade Heterobranchia. Sea angels were previously considered to be pteropods. Sea angels are also sometimes known as "sea butterflies" but this is potentially misleading because the family Clionidae is just one of the families within this clade, and the term "sea butterfly" is also applied to the shelled Thecosomata. 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. Distribution These organisms have a wide geographic range, from polar regions, under sea ice, to equatorial (tropic) seas. From spring to autumn, sea angels live at a depth of 200 m in the Sea of Okhotsk. In winter, they migrate to the coast of north ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthobranchia
Opisthobranchs () is a now 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 hear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaspidea
The order Aplysiida, 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 , 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 "Aplysiida". The original author Paul Henri Fischer described the taxon Aplysiida at unspecified rank above family. In 1925 Johannes Thiele established the taxon Aplysiida as a suborder. 2005 taxonomy Since the taxon Aplysiida was not based on an existing genus, this name is no longer available according to the rules of the ICZN. Aplysiida has been replace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thecosomata
The Thecosomata (collective/plural: ''thecosomes'', meaning "case/shell-body"), or sea butterflies, are a taxonomic suborder of small, pelagic, free-swimming sea snails known as holoplanktonic opisthobranch gastropod mollusks, in the order Pteropoda (also included within the informal group Opisthobranchia). Most pteropods have some form of calcified shell, although it is often very light, even translucent. The sea butterflies include some of the world's most abundant gastropod species; as their large numbers are an essential part of the ocean food chain, they are a significant contributor to the oceanic carbon cycle. Morphology Unlike other sea snails, or even land snails, sea butterflies float and swim freely through the ocean, traveling along with the currents. This has led to a number of evolutionary adaptations in their bodies, including complete or near-complete loss of the shell and the gill in several families. Their gastropodal foot has also taken the form of two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteropoda
Pteropoda (common name pteropods, from the Greek meaning "wing-foot") are specialized free-swimming pelagic sea snails and sea slugs, marine opisthobranch gastropods. Most live in the top 10 m of the ocean and are less than 1 cm long. The monophyly of Pteropoda is the subject of a lengthy debate; they have even been considered as paraphyletic with respect to cephalopods. Current consensus, guided by molecular studies, leans towards interpreting the group as monophyletic. Pteropoda encompasses the two clades Thecosomata, the sea butterflies, and Gymnosomata, the sea angels. The Thecosomata ( "case-body") have a shell, while the Gymnosomata ("naked body") do not. The two clades may or may not be sister taxa; if not, their similarity (in that they are both pelagic, small, and transparent, and both groups swim using wing-like flaps (parapodia) which protrude from their bodies) may reflect convergent adaptation to their particular lifestyle. Taxonomy The group Pteropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nudipleura
Nudipleura are a clade of sea snails and sea slugs, marine gastropod mollusks within the large clade Heterobranchia. Taxonomy 2005 taxonomy In the taxonomy of Bouchet & Rocroi (2005), the clade Nudipleura is arranged as follows: *Clade Nudipleura **Clade Pleurobranchomorpha **Clade Nudibranchia ***Family Bathydeviidae ***Clade Euctenidiacea ***Clade Dexiarchia ****Clade Pseudoeuctenidiacea ****Clade Cladobranchia *****Clade Euarminida *****Clade Dendronotida *****Clade Aeolidida The Aeolidida is a taxonomic clade of sea slugs, specifically aeolid nudibranchs, marine gastropod molluscs in the clade Cladobranchia. They are distinguished from other nudibranchs by their possession of cerata containing cnidosac A cnidosac ... 2010 taxonomy Jörger et al. (2010) have classified Nudipleura within Heterobranchia as a separate clade as follows: References External links Sea Slug Forum {{Taxonbar, from=Q4576637 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acochlidiacea
Acochlidiacea, common name acochlidians, are a Taxonomy (biology), taxonomic clade of very unusual sea snails and sea and freshwater slugs, aquatic animal, aquatic gastropod mollusks within the large clade Heterobranchia. Acochlidia is a variant spelling. Description These are mostly very small animals, without a Mollusc shell, shell or gills, distinguished by the visceral mass being sharply set off from the rest of the body. Being a small group with only 47 species worldwide known in 2023,MolluscaBase eds. (2021)MolluscaBase. Acochlidiimorpha.Accessed on 2023-02-13. this group has been the subject of active research since 2010, by which date only 32 species were named. 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 o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
