3. INTRODUCTION
• Fish are aquatic vertebrates with gills and fins rather than lungs and
legs.
• Fish represent huge diversity in shape, size, color, and habitat.
• In geologic time they preceded the other vertebrate groups which are
derived from them.
4. INTRODUCTION
• Fish share with vertebrates a basic body plan of bilateral symmetry,
with a dorsal supporting structure the notochord as a precursor to
the series of harder vertebrae.
• Currently, fish are the most numerous vertebrates representing
roughly 50 percent of al vertebrate species now alive.
• In 2016, Nelson reported 32,000 species of Fish.
5. CLASSIFICATION BY NELSON-1984
Phylum Chordata
Subphylum Vertebrata (Craniata)
Superclass Agnatha (Jawless Fish)
Class Cephalaspidomorphi
Subclass Cyclostomata
Order Myxiniformes (Hagfishes)
Order Petromyzoniformes (Lampreys)
7. CLASSIFICATION BY NELSON-1984
Phylum Chordata
Subphylum Vertebrata (Craniata)
Superclass Gnathostomata (Jawed Fish)
Class Chondrichthyes (Cartilagnous Fish)
Subclass Holocephali
Order Chimaeriformes (chimaeras)
8. CLASSIFICATION BY NELSON-1984
Phylum Chordata
Subphylum Vertebrata (Craniata)
Superclass Gnathostomata (Jawed Fish)
Class Chondrichthyes
Subclass Elasmobranchii (sharks and rays)
Order Heterodontiformes (Port Jackson shark)
Order Hexanchiformes (cow shark)
Order Squaliformes (dogfish)
Order Lamniformes (basking shark, mackerel shark)
Order Rajiformes (rays)
9. GNATHOSTOMATA-JAWED FISHES
Subclass: Holocephali
Order: Chimaeriformes
Family: Chimaeridae
Genus: Hydrolagus
Specie: H. colliei
Chimaeras
Subclass: Elasmobranchii
Order: Heterodontiformes
Family: Heterodontidae
Genus: Heterodontus
Specie: H. portusjacksoni
Port Jackson shark
Subclass: Elasmobranchii
Order: Hexanchiformes
Family: Hexanchidae
Genus: Hexanchus
Specie: H. griseus
Cow shark
10. GNATHOSTOMATA-JAWED FISHES
Subclass: Elasmobranchii
Order: Squaliformes
Family: Squalidae
Genus: Squalus
Specie: S. acanthias
Dogfish
Subclass: Elasmobranchii
Order: Lamniformes
Family: Cetorhinidae
Genus: Cetorhinus
Specie: C. maximus
Baskingshark
Subclass: Elasmobranchii
Order: Rajiformes
Family: Aetobatidae
Genus: Aetobatus
Specie: A. narinari
Spotted eagle ray
11. CLASSIFICATION BY NELSON-1984
Superclass Gnathostomata
Class Osteichthyes (Bony Fish)
Subclass Crossopterygii
Order Coelacanthiformes (Latimeria)
Subclass Dipneusti (lungfishes)
Order Ceratodontiformes
Order Lepidosireniformes
Subclass Brachiopterygii (bichirs)
Order Polypteriformes (Polypterus)
13. CLASSIFICATION BY NELSON-1984
Superclass Gnathostomata
Class Osteichthyes (Bony Fishes)
Subclass Actinopterygii (ray-finned fishes)
Order Acipenseriformes (sturgeons and paddlefish)
Order Lepisosteiformes (gars)
Order Anguilliformes (eels)
Order Cypriniformes (carps, suckers, and loaches)
Order Salmoniformes (salmon)
14. GNATHOSTOMATA-JAWED FISHES
Subclass: Actinopterygii
Order: Lepisosteiformes
Family: Lepisosteidae
Genus: Lepisosteus
Specie: L. oculatus
Spotted gar
Subclass: Actinopterygii
Order: Anguilliformes
Family: Angullidae
Genus: Anguilla
Specie: A. Anguilla
European eel
Subclass: Actinopterygii
Order: Acipenseriformes
Family: Acipenseridae
Genus: Acipenser
Specie: A. oxyrinchus
Sturgeon
15. GNATHOSTOMATA-JAWED FISHES
Subclass: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Cyprinus
Specie: C. carpio
Common carp
Subclass: Actinopterygii
Order: Salmoniformes
Family: Salmonidae
Genus: Salmo
Specie: S. sala
Atlantic salmon
16. CLASSIFICATION BY NELSON-1984
Superclass Gnathostomata
Class Osteichthyes (Bony Fishes)
Subclass Actinopterygii (ray-finned fishes)
Order Beloniformes (flying fishes)
Order Lophiiformes (anglerfishes)
Order Siluriformes (catfishes)
Order Gasterosteiformes (sticklebacks)
Order Tetraodontiformes (triggerfish)
19. CLASSIFICATION BY NELSON-2016
• Nelson and colleagues separated the hagfish from the lampreys and all
other extant fish on the basis of lack of any vertebral elements in hagfish.
• There is a small group of ‘relict fish’ (lungfish, coelacanth, and bichirs)
which show a variety of primitive characteristics indicating their status as
remnants of very ancient lineages.
• Class Osteichthyes now have two Subclasses.
Subclass Actinopterygii (most bony fish)
Subclass Sarcopterygii (bony fish species close to terrestrial vertebrates)
20. CLASSIFICATION
BY NELSON-
2016
Phylum Chordata
Subphylum Craniata
Infraphylum Myxinimorpha (Hagfish)
Infraphylum Vertebrata (Vertebrates)
Superclass Petromyzontimorphi (Lampreys)
Superclass Pteraspidomorphi
Superclass Anaspidomorphi
Superclass Thelodontimorphi
Superclass Osteotracomorphi
Superclass Gnathostomata (Jawed Fish)
Class Chondrichthyes_ according to old classification
Class Osteichthyes
Subclass Actinopterygii
Subclass Sarcopterygii
21. REFRENCE
BOOK: ESSENTIAL FISH BILOLOGY: Diversity, Structure, and Function
AUTHORS: DEREK BURTON AND MARGARET BURTON