Bivalvia
Also known as bivalve, bivalves
thumb|alt=Shell of the giant clam (Tridacna gigas)|Empty shell of the giant clam (Tridacna gigas) thumb|alt=Sword razor|Empty shells of the Ensis ensis|sword razor (Ensis ensis) Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills hav
AI overview
Bivalves are aquatic molluscs with soft bodies enclosed in a pair of hinged, hard shells called valves, and they include familiar creatures like clams and mussels found in both ocean and freshwater environments. These animals lack a head and some organs that other molluscs possess, making them structurally distinct within their larger group.
AI-generated from the Wikipedia summary — may contain errors.
Species
bivalves
Bivalvia
CLASS
- KingdomAnimalia
- PhylumMollusca
- ClassBivalvia
Habitatmarine, brackish, freshwater
Observations9
双壳纲（學名：Bivalvia），又名斧足綱或瓣鰓綱，是软体动物门的一个纲，生于海洋及淡水地区因有两片贝壳而得名。有7500种左右，体长达135公分。本纲动物的头部已经退化，足部呈斧状，体躯两侧各有1对瓣状的鳃。壳侧生，开的过程是被动的，其关闭则需要相关肌肉的收缩完成。纤毛抖动在腮部扬起漩涡，使得水及其中的颗粒进入鰓部。口通过一条粘膜道以及触须吸取营养颗粒， 双壳类软体动物的许多种是重要的养殖和捕捞对象，如珍珠贝等。 目录 1 命名問題 2 分類 3 參考文獻 4 外部連結 命名問題 「雙殼綱」這個名稱由林奈命名，一直用到現在。其間有其他貝類學家建議過其他名稱，當中以斧足类（Pelecypoda Goldfuss, 1820）及瓣鳃类（Lamellibranchia de Blainville, 1824）[4]這兩大陣營最為常見[5]。部份1960年代出版的文獻仍然使用這兩個名稱[4]。然而由於兩邊陣營支持者相當，爭持多年仍然沒有結果，相反「雙殼綱」這名稱簡單易明，使這個相對較為「中立」的名稱變得更為可取。所以從Cox開始，貝類學家慢慢都轉回使用這個舊稱。 分類 在2010年5月，一個有關雙殼綱的新分類在期刊《Malacologia》發表。在這篇論文中，作者使用了多種系统发生学的資訊，例如：分子分析學，解剖分析學，外殼形態學及外殼微構造等方法，去把本綱的物種重新分類。根據這個新的分類，雙殼綱的物種可以分成324個有效的科，當中有214個科只有化石樣本，110個物種延續至現在[6]。 另外根據Bieler et al. (2014)的研究綜合了分子生物學及傳統的形態學分類，確認雙殼綱物種可分成兩大支序：原鰓類（Protobranchia）及Autobranchia，而後者又可再分為 翼形類（Pteriomorphia）及異殼類（Heteroconchia）。異殼類然後又再可分成古异齿亚纲（Palaeoheterodonta）及异齿亚纲（Heterodonta）；而異齒亞綱又可再分為始异齿下纲（Archiheterodonta）及真异齿下纲（Euheterodonta）兩個支序。為免這些假設的分支把林奈分類愈分愈細微，原鰓類到異殼類的這兩級分支繼續維持作支序來看待 [3][7]。 以下分類總覽雙殼綱物種的目級以上總屬群組名稱（Suprageneric Group Name）[8]，各分元的詳細組成請參閱各自的條目[3]： 异齿亚纲（Heterodonta） 始异齿下纲（Archiheterodonta） 心蛤目（Carditoida）：四個科 真异齿下纲（Euheterodonta） Unassigned Euheterodonta：四個科 异韧带目（Anomalodesmata）：16個科 海螂目（Myoida）：四個科 滿月蛤目（Lucinoida）：兩個
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Article
35 sectionsContents
- Etymology
- Anatomy
- Mantle and shell
- Muscles and ligaments
- Nervous system
- Senses
- Circulation and respiration
- Digestive system
- Modes of feeding
- Digestive tract
- Excretory system
- Reproduction and development
- Comparison with brachiopods
- Evolutionary history
- Diversity of extant bivalves
- Distribution
- Behaviour
- Predators and defence
- Mariculture
- Use as food
- Viral and bacterial infections
- Paralytic shellfish poisoning
- Amnesic shellfish poisoning
- Ecosystem services
- Other uses
- Pearls and mother-of-pearl
- Symbolism
- Bivalvian taxonomies
- Practical taxonomy of R.C. Moore
- 1935 taxonomy
- Taxonomy based upon hinge tooth morphology
- Taxonomy based upon gill morphology
- 2010 taxonomy
- References
- Further reading
thumb|alt=Shell of the giant clam (Tridacna gigas)|Empty shell of the giant clam (Tridacna gigas) thumb|alt=Sword razor|Empty shells of the Ensis ensis|sword razor (Ensis ensis) Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidia, specialised organs for feeding and breathing.
Common bivalves include clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. Majority of the class are benthic filter feeders that bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as scallops and file shells, can swim. Shipworms bore into wood, clay, or stone and live inside these substances.