The sharks, rays, and chimaeras make up the second group of fish, the Class Chondrichthyes. Chondrichthyes consists of two groups, Holocephali and Elasmobranchii , and within Elasmobranchii are eight (8) orders of sharks. Chondrichthyes is a class of jawed fishes having a cartilaginous skeleton. Like other fish skeletons you’ve seen, you’d expect a rib cage and hard bones to reveal themselves as the animal decayed. The tail has two lobes, the upper lobe is elongated and vertebrae extends into it and a shorter lower lobe, … Mostly marine. Phylum - Chordata - Division In Vertebrata: Cyclostomata, Pisces, Chondrichthyes, Osteichthyes, Amphibia, Amphibia, Reptilia, Aves, Mammalia. Placoderms. Chondrichthyes: (Gr., chondros = cartilage; ichthys = fish). Yet sharks are unique. Sharks are one of the earliest known jawed fishes. Scallops of the placoid type, exclusive of this group – are scales similar to small teeth, formed by dentin and a type of enamel (enamel is a highly mineralized tissue, very hard, of epidermal origin, as opposed to dentin and bone, of origin mesodermic), immersed in the body of the animal (the tip of the scale breaks the skin), giving a rough, “sandpaper” texture. Holocephali – Chimaeras Chimaeras are sometimes called ghost fish, ratfish or rabbit fish. The skeleton is composed of cartilage and, although often calcified (especially in the vertebrae), lacks true bone (except in the roots of teeth). Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nostrils, scales, two-chambered hearts, and skeletons made of cartilage rather than bone.They are divided into two subclasses: Elasmobranchii (sharks, rays and skates) and Holocephali (chimaera, sometimes called ghost sharks). Examples – Climatius, Dinichthys. Chondrichthyan - Chondrichthyan - Form and function: The elasmobranchs are fishlike vertebrates that differ from bony fishes in many respects. Sharks are one of the earliest known jawed fishes. Sharks belong to the superorder Selachimorpha in the subclass Elasmobranchii in the class Chondrichthyes.The Elasmobranchii also include rays and skates; the Chondrichthyes also include Chimaeras.It was thought that the sharks form a polyphyletic group: some sharks are more closely related to rays than they are to some other sharks, but current molecular studies support monophyly of … Class 1. They are cartilaginous fish along with skates, rays and chimeras. Quizlet flashcards, activities and games help you improve your grades. They have no bony skeleton. Sharks are classified as follows: Kingdom Animalia Phylum Chordata SubPhylum Vertebrata Class Chondrichthyes (cartilaginous fish) Subclass Plagiostomi (sharks and rays: upper jaw hung from skulls and different kind of blood) Superorder Selachimorpha (sharks: free upper eyelids, gill openings on the head, and pectoral fins separate from … They have an upper and lower jaw made of cartilage. Placodermi: Several extinct orders of primitive earliest jawed fishes of Palaeozoic with bony head shield. Imagine finding a dead shark on a beach. Class 2. There are five to seven fully developed gill clefts, opening separately to the exterior. Cartilaginous endoskeleton. Source | Credits | Picture Credits: NCERT General Science Phylum - Chordata Animals belonging to phylum Chordata are fundamentally characterised by the presence of a notochord, a dorsal hollow nerve cord and paired pharyngeal gill … Mr. Christian's class at KOHS Chondrichthyes study guide by KaylaToi includes 47 questions covering vocabulary, terms and more. 3. The class includes a diverse group of fishes including sharks, rays, skates and chimaeras. There are over 350 species of sharks known worldwide. Class Chondrichthyes. Taxonomy. A full-sized functional gill-arch precedes hyoid arch. Elasmobranchii (/ ɪ ˌ l æ z m ə ˈ b r æ ŋ k i aɪ /) is a subclass of Chondrichthyes or cartilaginous fish, including the sharks (superorder Selachii) and the rays, skates, and sawfish (superorder Batoidea). 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