Gnathostomata.pptx. with general characters & classification for bsc students
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; Internal 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
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 1. Rhynchocephalia (Gk., Rhynchos = a
beak/snout; Kephale = a head)
2. Squamata (Latin, sqamatus = scaly)
Suborder 1– Lacertilia (Lizards)
Suborder 2 Ophidia (Snakes)
3. 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
17. 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
