Class Pisces. General characteristics and classifications of Super Class Pisces

General characteristics and classification of Class Pisces

1. TUMKUR UNIVERSITY Accredited by NACC: B+ Grade University in Tumkur , Karnataka DEPARTMENT OF STUDIES AND RESEARSH IN ZOOLOGY Paper: CPT – 1.1. Animal systematics   Seminar Topic: General characters and classification of Class Pisces   Guided by, Presented by, Dr. Asiya Nuzahat Aafiya M Co-ordinator I MSc. 1 st Semester DOSR in Zoology DOSR in Zoology Tumkur University Tumkur University Tumakuru, Karnataka Tumakuru, Karnataka 2023 – 2024 

2. PISCES

3. Content Introduction General characters Classification Conclusion

4. Intoduction : The Superclass Pisces (L. Piscis = fish) Truly jawed vertebrates . They have organs of respiration and locomotion related to a permanently aquatic life. The respiratory organs are the gills and the organs of locomotion are paired and unpaired fins. All are poikilothermous . Kingdom: Animalia Phylum: Chordata Class: Pisces

5. General Characters of class Pisces: Habitat: Aquatic – freshwater or marine Body: streamlined and differentiated into head, trunk and tail. External Morphology: mouth, nostrils, eyes, gills, operculum (present or absent), fins, lateral line, vent, scales. Locomotion: paired pectoral and pelvic fins along with median dorsal and caudal fins. Exoskeleton: dermal scales or bony plates. Endoskeleton: bone or cartilage. Lateral line system is well developed.

6. Respiration: Gills, naked or covered by operculum Circulatory system: Closed type. Heart: 2 chambered, one auricle and one ventricle. Digestive system: Alimentary canal with definite stomach and pancreas and terminates into cloaca. Nervous system: 2 parts, central (brain and spinal chord) and peripheral (nerves found throughout the body) Excretory system: Mesonephric kidneys, Excretions ureotelic Buoyancy: Air bladder Reproduction: unisexual, sexual reproduction, Gonads typically paired. Gonoducts open into cloaca or don't , Males with or without claspers. Fertilization: internal or external. Oviparous or ovoviviparous Development usually direct without or with little metamorphosis

7. Classifications: Romer (1959): Chondrichthyes and Osteichthyes Parker and Haswell (1962): Placodermi.

8. Important features of Chondrichthyes: Presence of a cartilaginous endoskeleton. The mouth is placed ventrally. The operculum does not cover the gills. The absence of an air bladder. Claspers and cloaca present. Sharks, Rays, Skates, saw fish, Chimaeras Sharks Rays, saw fish Chimaeras

9. Subclass 1. Selachii (Gr., selachos = a shark) Paired fins without a median axis. Base of pectoral fin constricted and pectoral radials jointed. Gill-slits numerous on either side and each is protected by independent skin flaps. Presence of a spiracle behind each eye. Tail is heterocercal. 2 suborders: Pleurotermata and Hypotermata

10. Pleurotermata or Squaliformes: (Gr., pleuro = side; trema = opening) Body typically spindle-shaped. Gill-slits lateral, 5-7 pairs. Spiracles small. Hyomandibular bearing branchial rays. Sharp head, dorsal fins which usually possess spines Examples: Dogfishes ( Scoliodon , Chiloscyllium , Mustelus,Carcharinus ).

11. Order 2. Rajiformes or Hypotremata (Gr., hypo = below; trema = opening) 1. Body depressed, flattened dorsoventrally. 2. Gill-slits ventral, 5 pairs. 3. Pectoral fins enlarged, fused with sides of the head and body. 4. Spiracles large. E xamples : skates and rays.

12. Sub-Class : Bradyodonti : Bradyodonti , an extinct order of cartilaginous fishes (class Chondrichthyes) that lived in the Paleozoic Era. Mouth is small and bounded by lips. Hyostylic jaw suspension is seen. Gill opening are enclosed in boneless operculum. Male possesses a frontal clasper on the heed . 2 orders: Eubradyodonti and Holocephali

13. Order Holochephali : (Gr., holos = entire; kephale = head) 1. Single gill opening on either side covered by a fleshy operculum. 2. No scales, spiracles and cloaca. 3. Jaws with tooth plates. 4. Nasal opening single 5. Lateral line system with open groove. 6. Males with claspers. Cephalic clasper on the head of male. 7. Tail long and thin. Examples: Rat fishes or Chimeras. Order Eubradyodonti : It includes helodus helodus

14. Class. Osteichthyses a Telostomi Inhabit all types of water-fresh, brackish, or salt; worm or cold. Operculum is present . mouth ( terminal or subterminal) , Exoskeleton: scales ( ganoid, cycloid and ctenoid) Endoskeleton chiefly of bone. . A ir bladder is present. Claspers absent . Cloaca absent , anus present. locomotion: Fins , tail is homoceracle

15. Subclass I. Sarcopterygii (Gr., sarcos = fleshy; pterygium = fin) Paired fins leg-like or lobed, fleshy. caudal fin heterocercal. Popularly called fleshy or lobe finned. Sarcopterygii has been divided into two superorders or orders: Crossopterygii and dipnoi .

16. Order 1. Crossopterygii (Gr., crossoi = a fringe; pteryx = fin) Paired fins lobed covered with scales. Caudal fin three-lobed. Scales covered by a layer of cosmine . Premaxillae, maxillae and squamosal bones present. Spiracles present. Air-bladder vestigial. Examples: Latimeria , Coelacanihus (extinct).

17. Order 2. Dipnoi (Gr., di = double; pnoe = breathing) Cycloid scales covering the skin. Single gill-slit on either side present and covered by operculum. Tail fin symmetrical (diphycercal), with no trace of separate dorsal fins. spiracles absent. Air-bladder single or paired, lung-like. Premaxillae and maxillae absent. Lower jaw firmly fused to neurocranium (skull autostylic ). Stomach absent, intestine ciliated. No hepatic caeca. Spiral valve present. Examples : Lung fishes. Only three living genera : Neoceratodus , Protopterus and Lepidosiren .

18. Subclass II. Actinopterygii (Gr., actis = ray; pteryx = fin) Includes all ray-finned fishes. Paired fins thin and broad. One dorsal fin, may be divided. Tail generally homocercal, in a few heterocereal or semi-heterocercal. Scales either ganoid or reduced to thin horny structures or completely absent in some. Gil-slits covered by operculum. Spiracles absent.

19. Superorder A. Chondrostei 1. Primitive ray-finned fish or cartilaging ganoids. 2. Tail fin heterocercal. 3. Scales usually ganoid 4. Mouth opening large.

20. Order 1. Polypteriformes 1. Typical rhomboid ganoid scales. 2. Dorsal fin of eight or more finlets . 3. Pectoral fins with a small prominent scale, covered fleshy lobe. 4. Ossified skeleton. 5. Spiracles present. 6. Air-bladder bilobed opening into the intestine ventrally. Examples : Polypterus ( Bichir ).

21. Order 2. Acipenseriformes Body covered with five rows of bony scutes . Snout elongated, having barbles on the ventral surface. Caudal fin heterocercal. Jaws without teeth. Example: Acipenser (Sturgeon), Polydon (Paddle-fish).

22. Superorder B. Holostei (Gr., holos = entire; osteon = bone) 1. Intermediate ray-finned fish, transtional between Chondrostei and Teleostei. 2. Ganoid or cycloid scales. 3. Tail fin heterocercal. 4. Mouth opening small.

23. Order 1. Amiiformes Thin, overlapping cycloid scales. Caudal fin abbreviate heterocercal. Long dorsal fin. Snout normal rounded Presence of single swim bladder Example : Amia (Bowfin)

24. Order 2. Semionotiformes or Lepidosteiformes 1. Scales rhomboidal ganoid and in oblique rows. 2. Body elongated. 3. Nasal opening at the end of much elongated snout. 4. Caudal fin abbreviate heterocercal. 5. Vertebrae completely ossified. 6. Air-bladder cellular. Example : Lepidosteus or Lepisosteus (Garpike).

25. Superorder C. Teleostei (Gr., teleos = complete; ostgon = bone) Scales are cycloid, ctenoid or absent. Mouth terminal, small. Tail fin mostly heterocercal. Endoskeleton more or less bony. Single external gill-slit on each side of the head covered over by operculum 11. Advanced or modern ray-finned fishes.

26. Order 1. Clupeiformes Head and operculum not scaled. Single dorsal and a small ventral fin without spines. Ventral fin may be absent. Pelvic fins abdominal. Caudal fin homocercal. Air-bladder communicate with the pharynx. Vertebral centra completely ossified. Examples : Clupea (Herringer), Salmo (Atlantic salmon), Sardinops (Pacific sardine), Esox (Pike), Notopterus (Chital fish), Elops , Gadusia , Ilisha , etc.

27. Order 2. Scopeliformes 1. Deep sea fishes having phosphorescent organs. 2. Dorsal and anal fins without spines. An adipose fin present. 3. Mouth wide and provided with numerous small teeth. 4. Air-bladder absent. Example: Harpodon (Mumbai duck).

28. Order 3. Cypriniformes or Ostariophysi Fins either without spines or dorsal, anal and pectoral have a spine each. W eberian apparatus. Air-bladder connected with the pharynx by a duct. Representatives of this order are grouped in two divisions: Cyprini , Siluri . J aw teeth weak or absent. P haryngeal teeth strongly developed.

29. Division I. Cyprini 1. Body covered with scales or naked. Never covered with bony plates. 2. Third and fourth vertebra not fused with each other. Examples : Labeo (Rohu) Division Il. Siluri 1. Body naked, not covered by scales. 2. Maxillary bone reduced supporting the barbules. 3. Second, third, fourth and sometimes the fifth vertebrae are generally fused. Examples : Sacobranchus ( Singhi )

30. Order 4. Anguiliformes 1. Body elongated eel-like or snake-like. 2. Scales vestigial or absent. 3. Dorsal and anal fins long and confluent behind. 4. Pelvic fins, if present abdominal. 5. Fins devoid of spines. 6. Air-bladder with duct. Examples : Anguilla (Freshwater eel), Muraena (Moray).

31. Order 5. Beloniformes ( Synentognathi ) 1. Body elongated covered with cycloid scales. 2. Fins without spines. 3. Pectoral fins large and high on body. 4. Ventral (pelvic) fins abdominal. 5. Some of them are capable of jumping into the air and glide with the help of enlarged pectoral fins. Examples: Exocoetus and Cypselurus (Flying fishes),

32. Order 6. Syngnathiformes ( Solenichthyes ) Body, covered with protective layer of scales or bony rings. Snout tubular with suctorial mouth. Pectoral fins small, pelvics absent and a single dorsal fin present. Males possess brood pouch for the development of the young. Physoclistic . Examples : Hippocampus (Sea horse), Fistularia (Flute fish) Syngnathus (Pipe fish).

33. Order 7. Ophiocephaliformes or Channiformes Body covered with cycloid scales. Head depressed, covered with plate-like-scales. Fins without spines. Air-bladder very long and without duct. Accessory respiratory organs present. Physoclistic . Example: Ophiocephalus or Channa (Snake head fish).

34. Order 8. Symbranchiformes Body elongated eel-like or snake-like devoid of scales. Dorsal, caudal and anal fins continuous. Pectoral fins absent. Fins without spines Gill-slits single or join to form a transverse ventral slit. Air bladder absent. Examples: Amphipnous , Symbranchus (Bels),

35. Order 9. Mastacembeliformes Freshwater eel-like fishes. Dorsal, caudal and anal fins confluent Sometimes a small fin separate. Some free spines present in front of dorsal fin. Anal fin with three spines. Ventral (pelvic) fins absent, but pectoral fins present. Nostrils on tubular tentacles at the end of snout. Buccal cavity enlarged for air breathing, Physoclistic . Examples : Mastacembelus , Macrog-nathus .

36. Order 10. Perciformes or ( Percomorphi ) Two dorsal fins, ventral (pelvic) fins thoracic with not more than 6 rays. Fins usually with spines. Weberian apparatus absent. Air bladder without duct. Plysoclistic . Examples : Anabas (Climbing perch), Perca (Yellow perch), Lates ( Bhetki ).

37. Order 11. Scorpaeniformes 1. Enlarged heads and pectoral fins. 2. Projecting spines from gill-covering. Example : Pterois (Scorpion fish).

38. Order 12. Pleuronectiformes : Bottom dwellers Body flat, lying on one side. Head asymmetrical. Both eyes present on the upper or dorsal side and close to each other. Fins usually without spines. Air-bladder absent in adults. Examples: Synaptura , Pleuronectes , Solea (Flat fishes).

39. Order 13. Echeneiformes ( Discocephall ) Body covered with cycloid scales. First dorsal fin modified into a flat oval adhesive disc or sucker on head for attachment. It posses 12 to 18 transverse ridges which are modified spines. No spines in second dorsal and anal fins. Air-bladder absent. Example: Echeneis or Remora (Suckerfish).

40. Order 14. Tetradontiform ( Plectognathi ) Body usually globular. Body scales modified into spines. Scutes or bony plates cover the body. Strong jaws with a sharp beak: Gill-slits small like a hole on either side of fish in front of pectorals. Ventral fines thoracic or subthoracic . Air-bladder present or absent. Some inflate by swallowing water. Examples : Diodon (Porcupine fish), Terodon (Globe fish), Ostracion (Coffer fish or Trunk

41. Order 15. Lophiiformes ( Pediculati ) First ray of spinous dorsal fin placed on the head is transformed into a fishing organ consisting of a rod (illicium) and a lure called esca. Mouth large with long pointed teeth. Body with minute scales or scaleless . Pelvic fins present or absent. Pectorals well developed. Air-bladder absent. Luminescent organs present. Examples : Lophius and Antennarius (Angular fishes)-

42. Conclusion: Class: Pisces: Fishes are poikilothermic (cold-blooded), aquatic vertebrates with jaws. The streamlined body is divisible into head, trunk and tail.Locomotion is by paired and median fins. Their body is covered with scales. Respiration is through gills.The heart is two chambered with an auricle and a ventricle. There are two main types of fishes .( i ) Cartilaginous fishes, with skeleton made of cartilage.Example:Sharks , Skates. (ii) Bony fishes with skeleton made of bones.Example : Carps, Mullets

43. Reference: E.L. Jordan Dr. P.S. Verma. 2022 Chordate zoollogy . S.Chand publishing . Britannica : https://www.britannica.com/animal/scorpion-fish Slideshare : https://www.slideshare.net/AshokkumarBollapalli/pisces-general-characters-and-classification-copy Science direct : https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/pisces#:~:text=Within%20the%20class%20Pisces%2C%20there,%2D%20versus%20air%2Dbreathing).

44. Any questions?