|
Acochlidian
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 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 opisthobranch gastropods). Taxonomy Nils Hjalmar O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microhedylacea
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] |
Hedylopsacea
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 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 opisthobranch gastropods). Taxonomy Nils Hjalmar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudunela Cornuta Svg Hariadhi
''Pseudunela'' is a genus of minute sea slugs, acochlidians, shell-less marine or temporary brackish or brackish gastropod mollusks in the clade Acochlidiacea. ''Pseudunela'' is the only genus in the family Pseudunelidae. ''Pseudunela'' is the type genus of the family Pseudunelidae. Taxonomy Pseudunelidae was placed within the superfamily Strubellioidea in the taxonomy of Bouchet & Rocroi (2005). Pseudunelidae was subsequently placed within the (unranked) Hedylopsacea by Schrödl & Neusser (2010).Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". ''Zoological Journal of the Linnean Society'' 158: 124-154. . Species These are the different species in the genus ''Pseudunela'': * ''Pseudunela cornuta'' (Challis, 1970) - type species of the genus ''Pseudunela'', marine and temporary brackish * '' Pseudunela eirene'' Wawra, 1988 - The description of ''Pseudunela eirene'' is brief and based on a single ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pontohedyle Milaschewitchii
''Pontohedyle milaschewitchii'' is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Parhedylidae.Jörger K. M., Norenburg J. L., Wilson N. G. & Schrödl M. (2012). "Barcoding against a paradox? Combined molecular species delineations reveal multiple cryptic lineages in elusive meiofaunal sea slugs". ''BMC Evolutionary Biology ''BMC Ecology and Evolution'' (since January 2021), previously ''BMC Evolutionary Biology'' (2001–2020), is a peer-reviewed open access scientific journal covering all fields of evolutionary biology, including phylogenetics and palaeontology ...'' 12: 245. . Ecology The life cycle of all Acochlidiacea is not well known. ''Pontohedyle milaschewitchii'' lays a maximum of 40 eggs. References External links * Jörger K. M., Neusser T. P. & Schrödl M. (2007). "Re-description of a female ''Pontohedyle brasilensis'' (Rankin, 1979), a junior synonym of the Mediterranean ''P. milaschewitchii'' (Kowalevsky, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tantulidae
''Tantulum elegans'' is a species of freshwater slug, an aquatic shell-less gastropod mollusk within the clade Acochlidiacea. This species has no shell. The maximum recorded length is 2 mm.Welch J. J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. . ''Tantulum elegans'' is the only species in the genus ''Tantulum'', and that is in turn the only genus in the family Tantulidae.Strong E. E., Gargominy O., Ponder W. F. & Bouchet P. (2008). "Global Diversity of Gastropods (Gastropoda; Mollusca) in Freshwater". '' Hydrobiologia'' 595: 149-166. . Taxonomy In 2005, Tantulidae was classified as the only family within the superfamily Hedylopsoidea in the taxonomy of Bouchet & Rocroi. According to Schrödl & Neusser (2010)Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". ''Zoological Journal of the Linnean Society'' 158: 124-154. . Tantulidae i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asperspinidae
''Asperspina'' is a genus of sea slugs, marine gastropod mollusks within the clade Acochlidiacea. Taxonomy Asperspinidae has been listed as a synonym of Parhedylidae in the taxonomy of Bouchet & Rocroi (2005). Sensu Schrödl & Neusser (2010)Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". ''Zoological Journal of the Linnean Society The ''Zoological Journal of the Linnean Society'' is a monthly peer-reviewed scientific journal covering zoology published by Oxford University Press on behalf of the Linnean Society. The editor-in-chief is Maarten Christenhusz (Linnean Society) ...'' 158: 124-154. . is ''Asperspina'' is the only genus in the family Asperspinidae. Minicheviellidae is a junior synonym of Asperspinidae. Species Species within the genus ''Asperspina'' include: * '' Asperspina brambelli'' (Swedmark, 1968) * '' Asperspina murmanica'' (Kudinskaya & Minichev, 1978) - synonym: ''Minicheviel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc Shell
The mollusc (or mollusk) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and neomeniomorpha, solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although these terms used to be, and to a minor extent still are, used interchange ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamella (surface anatomy), lamellae (folds) contain blood or Coelom#Coelomic fluid, coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including Mollusc, molluscs, crustaceans, insects, fish, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscera
In a multicellular organism, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a function. Tissues of different types combine to form an organ which has a specific function. The intestinal wall for example is formed by epithelial tissue and smooth muscle tissue. Two or more organs working together in the execution of a specific body function form an organ system, also called a biological system or body system. An organ's tissues can be broadly categorized as parenchyma, the functional tissue, and stroma, the structural tissue with supportive, connective, or ancillary functions. For example, the gland's tissue that makes the hormones is the parenchyma, whereas the stroma includes the nerves that innervate the parenchyma, the blood vessels that oxygenate and nourish it and carry away its metabolic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonochorism
In biology, gonochorism is a sexual system where there are two Sex, sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contrasts with simultaneous hermaphroditism but it may be hard to tell if a species is gonochoric or Sequential hermaphroditism, sequentially hermaphroditic e.g. parrotfish, ''Patella ferruginea''. However, in gonochoric species individuals remain either male or female throughout their lives. Species that reproduce by Thelytokous, thelytokous parthenogenesis and do not have males can still be classified as gonochoric. Terminology The term is derived from Greek language, Greek ''gone'' 'generation' + ''chorizein'' 'to separate'. The term gonochorism originally came from German ''Gonochorismus''. Gonochorism is also referred to as unisexualism or gonochory. Evolution Gonochorism has Convergent evolution, evolved independently multiple ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acochlidium Fijiiensis
''Acochlidium fijiiensis'' is a species of freshwater slug, an aquatic gastropod mollusc within the family Acochlidiidae. This species lives in two rivers on Fiji.Rudman W. B. (23 March 2010). "''Acochlidium fijiiensis'' Haynes & Kenchington, 1991". ''Sea Slug Forum''. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/acocfiji accessed 23 may 2010. References Further reading * Haase M. & Wawra E. (1996). "The genital system of ''Acochlidium fijiense'' (Opisthobranchia: Acochlidioidea) and its inferred function". ''Malacologia ''Malacologia'' is a peer-reviewed scientific journal in the field of malacology, the study of mollusks. The journal publishes articles in the fields of molluscan systematics, ecology, population ecology, genetics, molecular genetics, evolution, an ...'' 38: 143-151. * External links * https://web.archive.org/web/20110727113118/http://www.naturefiji.org/endspecies.php?info=Acochlidium%20fijiense Acochlidiidae Gastropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
