Published on March 4, 2014
Class Chondrichthyes Mirabel, Camille Joyce Mercado, Pia Alyssa Rivera, John David
ETYMOLO G Y - Cartilages “Chondros’’ “Ichthyos’’ - Fish
Class Chondrichthyes Characteristics: Cartilaginous fishes Streamlined form with heterocercal tail Cartilaginous skeleton Leathery skin With placoid scales ( dermal denticles ) Restricted notochord Mouth and two nostrils ventral Jaws and paired appendages Male claspers Eggs with large yolk
M O R P H O L O G Y
Taxonomical Hierarchy Kingdom Animalia Phylum Chordata Subphylum Vertebrata Infraphylum Gnathostomata Class Chondrichthyes Subclass Elasmobranchii Orders Cladoselachii, Pleuracanthodii ( extinct sharks ) Orders Squaliformes Order Rajiformes Subclass Holocephali
Subclass Elasmobranchii Sharks (Selachii) and the rays & skates (Batoidea) lives in most oceans in the world
Circulatory System Four chamber heart: sinus venosus, atrium, ventricle, and conus arteriosus. One direction of flow: Heart Gills Body Ectotherms/Endotherms
Reproductive System (Male) Both testes functional Seasonal reproduction cycle Sperm stored in seminal vesicles Both claspers functional
Reproductive System (Female) One functional ovary in most viviparous species Seasonal reproductive cycle Fertilization in nidamental gland
Shark Mating One clasper will rotate 90º and will be inserted into the female’s cloaca Clasper will expand cartilaginous spurs to anchor in the female
Subclass Elasmobranchii: Orders Cladoselachii, Pleuracanthodii extinct sharks
Order Squaliformes sharks, body spindle-shaped; 5-7 pairs of lateral gills not covered by operculum, pectoral fins not enlarged example: Squalus
Order Rajiformes skates, rays and sawfishes, body spreadout, pectoral fins enlarged and attached to head and body; five pairs of gill slits on ventral side, spiracles large
Subclass Holocephali • • • • chimaeras or ghost fish , gill slits covered with operculum; spirally closed; aberrant shaped; jaws with tooth plates; single nasal opening without scales; accessory clasping organs in male ; lateral line an open groove, Chimaera
Nervous System Cerebellum is small Medulla Oblongata is produced laterally into restiform bodies
Digestive System The mouth in holocephali is small as compared to the wide mouth of Elasmobranch It is bounded by three lips-like fold and equipped with the tooth plate having irregular surface and sharp cutting Edges
Urogenital System The kidney of holocephalians is opisthonepric having a large number of uriniferous tubules and built upon the basic pattern other fishes.
Circulatory System Heart is Built upon the pattern similar to other fishes. The Heart is consists of a sinus venosus, artrium, ventricle and conus with three rows of valves.
Respiratory System A Mandibular pseudobranch is absent and hyoid bear only a Posterior Hemibranch. The first,second and the third branchial arches have Holobranch but the forth Has a hemibranch.
1. Class ChondrichthyesMirabel, Camille Joyce Mercado, Pia Alyssa Rivera, John David. 2. ETYMOLO G Y - Cartilages “Chondros’’ “Ichthyos’’- Fish
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