Gnathostomata.pptx. with general characters & classification for bsc students

Gnathostomata

1. Superclass 2: Tetrapoda bear limbs Class 1: Amphibia Rana Class 2: Reptilia Varanaus Class 3: Aves Columba Class 4: Mammalia Lepus Superclass 1: Pisces Class 1: Placodermi (Extinct) Class 2: Chondrichthyes Scoliodon Class 3: Osteichthyes bear fins Gnathostomata : Classification

2. Super class: Pisces General characters All aquatic and cold blooded (ectothermic) fishes They are found in fresh, marine, and brackish water Body is long, spindle shaped and streamlined, which is divided into head, trunk and tail Body is covered by dermal scales, denticles or bony plates External and middle ears are absent Locomotion with the help of various fins Respiration by gills (Lungs in dipnoi fishes) Heart is two chambered , having one auricle and one ventricle Lateral line system is well developed-help to sense water current vibrations & disturbances in the nearby environment The digestive system is well-developed . The nervous system comprises of the brain and ten pairs of the cranial nerves . Fishes are unisexual Fertilization is internal or external Development is direct Oviparous, viviparous or ovoviviparous

3. Pisces: Classification Class 1: Placodermi (Extinct) Class 2: Chondrichthyes or Elasmobranchii Class 3: Osteichthyes Sub-class I - Selachii Order 1: Squaliformes or Pleurotremata Order 2: Rajiformes or Hypotremata Sub-class II - Holocephali Superorder 3: Teleostei Orders Superorder 1: Chondrostei Orders Polypteriformes Acipenseriformes Sub-class I — Sarcopterygi (fleshy fins) Order 1: Crossopterygi Order 2: Dipnoi Sub-class II — Actinopterygi (ray fins) Superorder 2: Holostei Orders Amiiformes Semionotiformes Mastacembeliformes Perciformes Scorpaenoformes Pleuronectiformes Echeneiformes Tetradontiformes Lophiiformes Clupeiformes Scopelifomes Cypriniformes Anguiliformes Beloniformes Syngnathiformes Ophiocephaliformes Symbranchiformes

4. Class 1. Placodermi Placodermi (Gr., plakos = plates; derma = skin) Several extinct orders of primitive earliest jawed fishes of Palaeozoic Bony head shield movably articulated with trunk shield Covered by heavy bony plates The heterocercal caudal fin is present Climatius

5. Sub-class — Holocephali Chondrichthyes or Elasmobranchii (Gr. chondros , cartilage; ichthys, fish) Mostly marine and carnivorous Cartilaginous endoskeleton; Mouth sub-terminal (ventral) Gill-slits not covered by operculum Skin with placoid scales; Tail –heterocercal; do not have air-bladders Unisexual fish, males having clasper for reproduction; I nterna l fertilization Sub-class — Selachii Spiracle behind each eye Gills in separate clefts Presence of cloaca Order 1: Squaliformes or Pleurotremata (Gr., pleuro = side; trema = opening) They have 5-7 pairs of lateral gill slits Scoliodon (Dogfish) Stegostoma (Tiger Shark) Order 2: Rajiformes or Hypotremata Depressed body and five pairs of ventral gill slits. Torpedo (Electric Ray) Pristis (Saw Fish) Class 2. Chondrichthyes or Elasmobranchii Order 1: Chimaeriformes Gill slits covered by fleshy operculum and a single gill opening Tail whip like spiracles, cloaca and scales absent Rat fishes or Chimaera/Ghost shark

6. Osteichthyes (Gr. osteon, bone; ichthys, fish) Freshwater and marine Endoskeleton mostly bony Cycloid, ctenoid and placoid scales Gill-slits covered by operculum They have no claspers The air bladders are present in most of them. Class 3: Osteichthyes Sub-class I — Sarcopterygi ( sarco = fleshy; pterygium = fins) Order 1: Crossopterygii Latimeria Order 2: Dipnoi Neoceratodus Sub-class II — Actinopterygi (ray fins) Superorder 1: Chondrostei Orders Polypteriformes Polypterus Acipenseriformes Acipenser Superorder 2: Holostei Orders Amiiformes Amia Semionotiformes Lepidosteus

7. Superorder 3: Teleostei Orders (15) Clupeiformes - Salmo (Altalntic salmon) Scopelifomes - Harpodon (Mumbai duck) Cypriniformes - Labeo (Rohu), Clarius (Magur) Anguiliformes - Anguilla (Freshwater eel) Beloniformes - Belone (Garfish) Syngnathiformes - Hippocampus (Sea Horse) Ophiocephaliformes - Channa (Snake head fish) Symbranchiformes - Symbranchus (Eels) Mastacembeliformes - Mastacembelus Perciformes - Anabus (Climbing perch) Scorpaenoformes - Pterois (Scorpion fish) Pleuronectiformes - Solea (Flat fish) Echeneiformes - Echeneis (Sucker fish) Tetradontiformes - Diodon (Porcupine fish) Lophiiformes - Lophius

8. Primarily terrestrial, some are secondarily aquatic Two pairs of pentadactyl limbs . Body covered by an exoskeleton of epidermal hair, feathers or scales . Lungs are main respiratory organs. Amphibian may respire by gills, skin or lungs. 3 or 4 chambered heart present. They are divided into 4 classes: Amphibia, Reptilia, Aves and Mammalia Superclass: Tetrapoda General characters Tetrapoda (Gr. tetra, four, podos, foot) Class 1 Amphibia. (Gr. amphi , both; bios, life) Rana Class 2. Reptilia. (L. reptilis , creeping) Hemidactylus (wall lizard), Uromastix (spiny-tailed lizard), Naja (cobra), Sphenodon, Crocodilus (crocodile). Class 3. Aves. (L. avis , bird) Struthio (African ostrich), Columba (pigeon), Gallus (fowl) Class 4. Mammalia. (L. mamma, breast) Echidna (spiny anteater), Macropus (Kangaroo), Rams (rat), Homo (man).

9. A caecilian Caecilia tentaculata Red-eyed tree frog Agalychnis callidryas An adult tiger salamander Ambystoma  tigrinum Class: Amphibia General characters Apoda (Gymnophiona or Caecilia ) Urodela (Caudata) Anura (Salientia) Lives in both on land and in water Skin moist, glandular and with no external scales They are ectothermic, cold-blooded They have two pairs of limbs for locomotion Heart is three chambered They possess ten pairs of cranial nerves. The lateral line is present during their development Development is indirect with metamorphosis Larval stage usually aquatic and breathes by gills Approximately 2,500 species

10. First class of organisms to adapt to life on land Terrestrial tetrapods , Cold-blooded Skin dry, covered by ectodermal horny scales or bony plates Three-chambered hearts except crocodiles which have four-chambered hearts Respiration by lungs Nervous system comprises 12 pairs of cranial nerves Reptiles are generally uricotelic Reptiles produce shelled eggs or bear live young. All species fertilize eggs internally 7,000 species. Class: Reptilia General characters

11. Reptilia: Classification Anapsida Parapsida (Extinct) Synapsia (Extinct) Diapsida Euryapsida (Extinct) Subclasses Skull with no temporal fossa One temporal fossa on each side Ichthyosaurus Only one temporal fossa Cynognathus Two temporal fossa on each side Order : Chelonia Rhynchocephalia (Gk., Rhynchos = a beak/snout; Kephale = a head) Squamata (Latin, sqamatus = scaly) Suborder 1– Lacertilia (Lizards) Suborder 2 Ophidia (Snakes) Crocodilia (Latin: Crocodilus = a crocodile) Order Only one temporal fossa Protorosaurs

12. The red-bellied turtle Pseudemys rubriventris Sri Lankan star tortoise Geochelone elegans Tuatara Sphenodon punctatus A collared lizard Crotaphytus collaris Smooth green snake Liochlorophis vernalis Crocodile Crocodylus acutus Gharial Gavialis gangeticus

13. Birds have spindle-shaped body is highly aero dynamically suitable and covered by fea­thers Mouth is provided with a specialized exoskeletal derivative called beak . Teeth are absent in Birds Fore limbs are modified as wings, which is powered by strong flight muscles Hind limbs of birds possess four clawed digits . Eyes of birds possess pecten. Bones become pneumatic to reduce body weight Specialised respiratory system performs double respiration . Air sacs are present in association with lungs. Syrinx is the sound producing organ. Heart of birds is four-chambered Only left ovary is present, oviparous animals Class: Aves General characters

14. Archaeornithes (Extinct) Archaeopteryx Subclasses Aves: Classification Neornithes Modern birds Superorders Odontognathe (Extinct) Hesperornis Paleognathae / Ratitae Flightless birds Ostrich, Emu, Kiwi Impennae Modern, aquatic, & flightless Penguins Neognathae/ Carinatae Modern flighing birds Sparrow, Pigeon, Pelicans, Egrets

15. Class: Aves

16. Class: Mammalia Prototheria Eutheria Metatheria General characters Mammals are a class of endothermic vertebrates and give birth to their younger ones Mammals have four limbs and produce amniotic eggs The mammal class is defined by the presence of mammary glands and hair (or fur) Mammals have a four-chambered heart Mammalian lungs have millions of tiny air sacs called alveoli Their skin possesses oil glands (sebaceous glands) and sweat glands They possess 12 pairs of cranial nerves Subclasses Short-nosed echidna Tachyglossus aculeatus Duck-billed platypus Ornithorhynchus anatinus Red kangaroo Macropus rufus Opossum Didelphis virginiana Lion Panthera leo Bottle-nosed dolphin Tursiops truncatus

17. Sub Class: Eutheria