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Presenters Dewan Rai Kinley Wangchuk Ngajay Tshering

What are Agatha and Gnathostomata . Describe the relation between the Cyclostoma (lamprey) with different groups of Pisces. Presenters Dewan Rai Kinley Wangchuk Ngajay Tshering. Vertebrata is divided into two groups on the basis of jaws. Agnatha gnathostoma/ gnatha. Agnatha.

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Presenters Dewan Rai Kinley Wangchuk Ngajay Tshering

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  1. What are Agatha and Gnathostomata.Describe the relation between the Cyclostoma (lamprey) with different groups of Pisces. Presenters DewanRai KinleyWangchuk NgajayTshering

  2. Vertebrata is divided into two groups on the basis of jaws. • Agnatha • gnathostoma/ gnatha

  3. Agnatha (Greek, "no jaws"), often considered a superclass within the subphylum vertebrata, comprises the jawless fish—the oldest known vertebrates. Examples; lamprey, hagfish

  4. Characteristics • Mouth is without jaws • Notochords persists through out life • Paired appendages are absent • Skins are soft and slimy without exo-skeleton This group has only one class i.e. Cyclostomes

  5. Cyclostomata • is a group of chordates that comprises the living jawless fishes: the lampreys and hagfishes. • Both groups have round mouths that lack jaws but have retractable horny teeth. The name Cyclostomata means "round mouths". Their mouths cannot close due to the lack of a jaw, so they have to constantly cycle water through the mouth.

  6. Characteristics 1. No true jaws-round mouth. 2. No true teeth-horny teeth composed of protein and located in the roof of the mouth.  They are used to rasp the scales and skin from the surface of a fish exposing blood vessel so that they can suck  the blood. 3. Adults parasitic feeding on blood-larvae filter feeders. 4. No scales -leathery skin.

  7. 5. No paired fins-single mid-dorsal fin present. 6. With a protocercal tail. 7. No swim bladder 9. With 7 pair of unprotected gill slits. 10. Notocord present throughout their life history.

  8. 11. External fertilization. 12. With extended larval stages. (Source:http://blue.utb.edu/rlnash/Spring2004/Notes/1307%20notes/Notes%20Fish.htm)

  9. Lamprey http://en.wikipedia.org/wiki/Lamprey

  10. lamprey • Are ectoparasite and sanguivorous • Attach to the body of the fishes and suck blood. • Anterior end bears a circular sucking disc and a suctorial cup shape mouth. • Paired fins are absent. • body has two dorsal and one caudal fins.

  11. 2. gnatha/gnathostomata • Gk. Gnathos= jaws, stoma= mouth. • Mouth is bounded by jaws • Notochord is replaced by vertebral column • Paired appendages • Skins soft and slimy, or dry and covered with scales, feathers and hairs. • It is classified into two supper classes: • Pisces • tetrapods

  12. Pisces Pisces include the fishes which are aquatic. They have fins for locomotion and gills for respirartion. Fishes can be broadly classified into two main class: • Chondrichthyes • osteichthyes

  13. Chondrichthyes • Cartilaginous fish Gk. Chondron= cartilage, ichthyes= fish. Example: sharks, dog fish(scoliodon) etc

  14. Characteristics • endoskeleton is cartilaginous • Posses paired jaws and paired fins. • Skin is rough, tough and with minute placoid scales. • Gills 5-7 pairs • No swim bladder • The tail is heterocercal

  15. 2. Osteichthyes Gk. Osteos= bony, ichthyes= fish Those fishes which has bones as skeletons. Example: Sea horse, exocoetus(flying fish)

  16. Characteristics • Endoskeleton is bony • Has paired fins • Tail is heteroceral • Skin is either naked or either covered with epidermal scales. • Has four pairs of gills • Air bladder or swim bladder is present. • Has two chambered heart.

  17. Relationship between cyclostomata and different groups of Pisces Relationship between cyclostomes and Pisces Source: http://5science12011.blogspot.com/2010/09/biology-lamprey.html

  18. They feed on prey as adults by attaching their mouthparts to the target animal's body, then using their teeth to cut through surface tissues until they reach blood and body fluid. • Hagfish, which superficially resemble lampreys, are the sister taxon of the true vertebrates (lampreys and gnathostomes). Source: http://5science12011.blogspot.com/2010/09/biology-lamprey.html

  19. reference Rastogi V.B(2011). A complete Course inISC Biology(vol. ii).New Delhi: Pitambar Publishing Company (P) Ltd. Retrieved on May12, 2011 from http://5science 12011.blogspot.com/2010/09/biologylamprey. html Retrieved on May10, 2011fromhttp://en.wikipedia. org/wiki/Lamprey Retrieved on May10, 2011 fromhttp://blue.utb.edu /rlnash/Spring2004/Notes/1307%20notes /Notes%20Fish.htm

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