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Elasmobranchs
Sign in to saveAlso known as Elasmobranch, Elasmobranchii
Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks (division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by having five to seven pairs of gill slits opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch
Elasmobranchs are a group of cartilaginous fish that includes sharks, rays, skates, and sawfish, distinguished by features like multiple gill slits, rigid dorsal fins, and specialized tooth and jaw structures. They matter because understanding their anatomy and diversity helps scientists classify and study these important marine animals and their ecological roles.
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Species
hajartade fiskar
Class
- PhylumChordata
- ClassElasmobranchii
板鳃亞綱（學名：Elasmobranchii）屬於软骨鱼纲，包括鯊魚和鰩。鱼鳃是板状，鳃裂 5-7 对，鳃间隔宽大。体外是盾鳞或光滑，雄性腹鳍转化为鰭足，沒有魚鰾，仰賴富含油脂的魚肝維持浮力。 最早的板鰓亞綱化石發現於泥盆紀，現存大部分的目多在白堊紀或之前就已出現。許多物種在二疊紀絕種，也因此導致在侏儸紀時發生輻射適應。 目录 1 描述 2 演化 3 分类 4 参考文献 4.1 外部链接 描述 板鰓亞綱為軟骨魚綱下的兩個亞綱之一，另一個為全頭亞綱（銀鮫）。鳃裂 5-7 对，体外是盾鳞，沒有魚鰾，眼睛具有脈絡膜層（英语：tapetum lucidum），雄性腹鰭特化為鰭足。板鰓亞綱遍佈於熱帶與溫帶的水域中[2]。 許多魚類仰賴魚鰾維持浮力，但沒有魚鰾的板鰓亞綱物種則透過富含油脂的魚肝來維持浮力[3]。這些油脂在食物短少時也能作為暫時的營養來源[4][5]。其中深海鯊魚的肝重量可達體重 20%[6]，常被視為是漁業捕獲的目標。 演化 在約 4 億年前的泥盆紀早期就已經有發現鯊魚的牙齒化石，泥盆紀晚期時發現了幾乎完整的鯊魚（裂口鯊）化石。在石炭紀時，鯊魚開始演化出各種外型樣貌，不過多半於二疊紀絕種。其他鯊魚在侏儸紀時產生第二次的輻射適應，鰩和魟也約在這個時期出現。現存大部分的目多在白堊紀或之前就已出現[7]。 分类 本亚纲现存主要有两大类：鲨类和鳐类，分为如下各目： 鲨总目 Selachimorpha 虎鲨目Heterodontiformes 六鳃鲨目Hexanchiformes 鼠鲨目Lamniformes 角鲨目Squaliformes 锯鲨目Pristiophoriformes 鬚鮫目Orectolobiformes 真鲨目Carcharhiniformes（白眼鮫目） 扁鲨目Squatiniformes 鳐总目 Batoidea（魟总目） 鳐目Rajiformes 电鳐目Torpediniformes 鋸鰩目Pristiformes 燕魟目Myliobatiformes 参考文献 ^ Karatajūte, V. Elegestolepis grossi ge. et sp. nov., ein neues typ der placoidschuppe aus dem oberen Silur der Tuwa.. Palaeontographica Abteilung A. 1973, 143: 35–50. ^ Bigelow, Henry B.; Schroeder, William C. Fishes of the Western North Atlantic. Sears Foundation for Marine Research, Yale University. 1948: 64–65. ASIN B000J0D9X6. ^ Oguri,
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Research
12,937 papers- Elasmobranchs as bioindicators of pollution in the marine environment.ReviewMarine pollution bulletin · 2022Alves LMF, Lemos MFL, Cabral H et al.DOI: 10.1016/j.marpolbul.2022.113418
- Genetic damage in elasmobranchs: A review.ReviewEnvironmental toxicology and pharmacology · 2025Marques MB, Luvizotto-Santos R, Hauser-Davis RADOI: 10.1016/j.etap.2024.104607
- Forebrain organization in elasmobranchs.ReviewBrain, behavior and evolution · 2012Hofmann MH, Northcutt RGDOI: 10.1159/000339874
- DEVELOPING A THROMBOELASTOGRAPHY ASSAY IN ELASMOBRANCHS.Journal of zoo and wildlife medicine : official publication of the American Association of Zoo Veterinarians · 2024Bonadie KL, Lynch AM, Ruterbories LK et al.DOI: 10.1638/2023-0061
- Freshwater elasmobranchs: a review of their physiology and biochemistry.ReviewJournal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2010Ballantyne JS, Robinson JWDOI: 10.1007/s00360-010-0447-0
- Elements and elasmobranchs: hypotheses, assumptions and limitations of elemental analysis.ReviewJournal of fish biology · 2017McMillan MN, Izzo C, Wade B et al.DOI: 10.1111/jfb.13189
- Role of elasmobranchs and holocephalans in understanding peptide evolution in the vertebrates: Lessons learned from gonadotropin releasing hormone (GnRH) and corticotropin releasing factor (CRF) phylogenies.ReviewGeneral and comparative endocrinology · 2018Lovejoy DA, Michalec OM, Hogg DW et al.DOI: 10.1016/j.ygcen.2017.09.013
- Conservation genetics of elasmobranchs of the Mexican Pacific Coast, trends and perspectives.ReviewAdvances in marine biology · 2019Sandoval-Castillo JDOI: 10.1016/bs.amb.2019.08.002
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Wikidata facts
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- taxon name
- Elasmobranchii
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- Elasmobranchii
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- 400000000-
- taxon common name
- morski psi in skati
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Article
6 sectionsContents
- Description
- Evolutionary history
- Taxonomy
- See also
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Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks (division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by having five to seven pairs of gill slits opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil.
The definition of the clade is unclear with respect to fossil chondrichthyans. Some authors consider it as equivalent to Neoselachii (the crown group clade including modern sharks, rays, and all other descendants of their last common ancestor). Other authors use the name Elasmobranchii for a broader branch-based group of all chondrichthyans more closely related to modern sharks and rays than to Holocephali (the clade containing chimaeras and their extinct relatives). Important extinct groups of elasmobranchs sensu lato include the hybodonts (Order Hybodontiformes), xenacanths (order Xenacanthformes) and Ctenacanthiformes. These are also often referred to as "sharks" in reference to their similar anatomy and ecology to modern sharks.