Class chondrichthyes zoorepowt(1)
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The document discusses the class Chondrichthyes, which includes cartilaginous fishes such as sharks, rays, and skates. Key characteristics include a cartilaginous skeleton, placoid scales, ventral mouth and nostrils, jaws, paired appendages, and male claspers. The class contains two subclasses: Elasmobranchii containing sharks and rays/skates, and Holocephali containing chimaeras. Elasmobranchii have a four-chambered heart and seasonal reproduction cycles, while Holocephali have smaller mouths bounded by three lips and tooth plates instead of scales.
Class chondrichthyes zoorepowt(1)
- 1. Class Chondrichthyes Mirabel, Camille Joyce Mercado, Pia Alyssa Rivera, John David
- 2. ETYMOLO G Y - Cartilages “Chondros’’ “Ichthyos’’ - Fish
- 3. 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
- 4. M O R P H O L O G Y
- 5. 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
- 7. Circulatory System Four chamber heart: sinus venosus, atrium, ventricle, and conus arteriosus. One direction of flow: Heart Gills Body Ectotherms/Endotherms
- 8. Reproductive System (Male) Both testes functional Seasonal reproduction cycle Sperm stored in seminal vesicles Both claspers functional
- 9. Reproductive System (Female) One functional ovary in most viviparous species Seasonal reproductive cycle Fertilization in nidamental gland
- 10. 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
- 12. Order Squaliformes sharks, body spindle-shaped; 5-7 pairs of lateral gills not covered by operculum, pectoral fins not enlarged example: Squalus
- 13. 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
- 14. 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
- 15. Nervous System Cerebellum is small Medulla Oblongata is produced laterally into restiform bodies
- 16. 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
- 17. Urogenital System The kidney of holocephalians is opisthonepric having a large number of uriniferous tubules and built upon the basic pattern other fishes.
- 18. 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.
- 19. 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.