Some species have electric organs such as Torpedo and some bear poisonous sting such as Trygon. The tail is diphycercal with equally developed blades of fin above and below the notochord. Some taxonomists classify chimaeras into their own order. The Class Chondrichthyes (Elasmobranchii) is divided into two subclasses, Selachii and Bradyodonti: 1. 3. … Old teeth fall and are continuously replaced by the new teeth formed behind it. Chimaeras are sometimes called ghost fish, ratfish or rabbit fish. Other features found in Chondricthyes include similar coloration patterns, placoid scales, pectoral fins, and ampullae of lorenzini. Water is forced across the gill membranes, dissolved oxygen in the water is taken up by blood vessels and veins, while … The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulate… Question 10 Which of the following is not the characteristic feature of class Chondrichthyes A They have cartilaginous endoskeleton B Skin is tough, containing minute cycloid scales C Air bladder is absent D Some of them have electric organs and poison sting. Chondrichthyan - Chondrichthyan - Form and function: The elasmobranchs are fishlike vertebrates that differ from bony fishes in many respects. The extra claspers are on the head and in front of the ordinary pair on the abdo­men. Order 3. Pelvic claspers; Teeth unattached to the Jaw. Devonian to Recent. Animals, Biology, Class Chondrichthyes, Classification of Class Chondrichthyes, Diversity, Zoology. 2. The tail has two lobes, the upper lobe is elongated and vertebrae extends into it and a shorter lower lobe, giving rise to the distinct heterocercal tail. The world`s largest member of Chondrichthyes is the plankton-feeding whale sharks (Rhincodon typus) which can grow up to 18 meters (60 feet) in length with 21.5 tonnes in weight and live up to 130 years. Hypotremata (Batoidea, Rajiformes): 1. They contain 5-7 pairs of gills. very light & strong. Created by. Chimaeras also have some characteristics of bony fishes. Cartilaginous Fish (Class: Chondrichthyes) Chondrichthyes include the sharks, and rays. Sharks with teeth adapted for shearing and sawing are aided in biting by body motions that include rotation of the whole body, twisting movements of the head, and rapid vibrations of the head. Chondrichthyes are a class of vertebrates comprising about 1200 species including sharks, rays and chimaeras. Spiral valve is present in the intestine. Gravity. Most Chondrichthyes show a massive growth. Curiously, echinoderm larva are bilaterally symmetrical and must convert to radial symmetry. Chondrichthyes is a class of jawed fishes having a cartilaginous skeleton. Eggs large and yolky. About 25 species are found in cold ocean waters down to 1,800 meter. An echinoderm usually has 5 parts, making them pentamerous. 2. 2. Some of them possess electric organs or poison sting, which are used for defence as well as predation. Primitive bradyodonts, remarkable for their dentition. There are just under 1000 living species, all of which have … Class-2: Chondrichthyes. Vertebral Column - Duration: 2:12. av9513 9,816 views. 1. 3. There are five to seven fully developed gill clefts, opening separately to the exterior. These fishes have teeth-like scales, denticles, which include the sharks, rays, skates and ratfishes. 9. Teeth numerous, developed in con­tinual succession. An adult echinoderm is radially symmetrical, meaning their body parts extend outward from the mouth. The class Chondrichthyes consists of the cartilaginous fishes, including sharks, batoids (rays, skates, guitarfish, and sawfishes), and chimaeras, or ratfishes. Their mouth is usually located ventrally and they were the first fishes to have paired fins (pectoral and pelvic fins) for more efficient swimming. The skin is tough, possesses minute placoid scales and mucous glands. Weve kept them in this order because of their historical classification in the Chondrichthyes. They are embedded in the tissue. The class Chondrichthyes has two subclasses ; Elasmobranchii, which includes the sharks and rays. Pronunciation: ee-LAZ-mo-brank. They have 5-7 pairs of gill slits without operculum. Osteichthyes excludes the jawless fishes of the class Agnatha (hagfishes and lampreys) and the cartilaginous fishes constituting the class Chondrichthyes (sharks, skates, and rays) but includes the 20,000 species and more than 400 families of modern bony … They are predatory fishes, they feed on other fishes, crustaceans and molluscs. 4. 3. 1. Traits that make sharks and rays successful predators include. They filter food particles like planktons from the water current that passes through the mouth, pharynx and gills. Before publishing your Notes on this site, please read the following pages: 1. Pectoral fins enlarged, joined to the sides of the body or to the head. But they show many resemblances with the bony fishes. semi-calcified. The class includes sharks, rays and chimaeras. "They resemble the true fishes in external form, but differ from them so widely in structure that they are placed in a class by themselves." 3. class of cartilaginous fish whose exoskeleton is made up of cartilages This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. The hyomandibular lacks rays, and takes no part in the support of the gill; ceratohyal is segmented and attached to the hyomandibular—either high up or not at all. They contain cartilaginous endoskeleton, the deposits of calcium salts provide strength to it. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. 8. Animals belonging to phylum Chordata are fundamentally characterised by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal [relating to the pharynx] gill slits. Modern Chondricthyes include the sharks, rays and Chimeras. They have a four-chambered heart. 10. Most sharks and rays fertilize their eggs. 2.These fish have dorsal fins, an anal fin, a pair of ventral fins and a single caudal fin. ADVERTISEMENTS: 3. Chondrichthyan, (class Chondrichthyes), also called chondrichthian, any member of the diverse group of cartilaginous fishes that includes the sharks, skates, rays, and chimaeras. The nostril one or two, never open in the mouth cavity. The Condrichthyes class includes only one other subclass, the Holocephali (chimaeras), which are unusual fish found in deep water. View User Profile View Posts Send Message Adventurer; Join Date: 4/22/2018 Posts: 3 Member Details; The CFV have already been … Cartilaginous skeletons No swim bladder. The vertebrae are complete and separate. It also has sensory cells in the lateral line organ, which detect all the kinds of vibration, motion, water pressure surrounding them. 6. The class includes a diverse group of fishes including sharks, rays, skates and chimaeras. 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Chondrichthyan - Chondrichthyan - Annotated classification: The most recent approaches to a comprehensive review of the chondrichthyans are those of Canadian ichthyologist J.S. Internal fertilization. Pleuracanthodii (Ichthyotomi): Devonian-Triassic: 1. Our mission is to provide an online platform to help students to discuss anything and everything about Zoology. Characteristics of Chondrichthyes Chondrichthyes share many common characteristics among each other; their main defining feature is having a cartilaginous skeleton. 4. A light cartilage skeleton Backward-pointing denticles Ampullae of Lorenzini Lateral lines. The skeleton is composed of cartilage and, although often calcified (especially in the vertebrae), lacks true bone (except in the roots of teeth). (gas exchange between water and blood). Cloaca has a dual function in females and also acts as a reproductive organ apart from excretion. The largest shark is the _____, which eats _____. 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