Chapter 13: Primative Fishes...

1. Chapter 13: Primative Fishes...

2. Polypteriformes • Primitive Traits • Ganoid Scales • Lung-like gas bladder –gulp air &survive in low O2 • Spiracle • Spiral Valve • Heterocercal Tail • Unique Traits • “Lobed” Fins – coelocanths or lungfishes • Dorsal fins – 5 – 18 separate dorsal fins • Restricted to Africa; aquarium fish; “birchirs”

3. Polypteriformes- coelocanth, ancient fish??

4. Polypteriformes- lungfish

5. Bichir

6. Acipenseriformes: • Cartilaginous skeletons lacking central vertebral • Strongly heterocercal tail • Anus and urogenital openings at base of pelvic fins • Spiracle present in some species • Conus arteriosus with multiple valves • Spiral valve present in intestine

7. Acipenseriformes: • Sturgeons: • Bony scutes • Sensory barbels • Mostly freshwater —few marine and anadromous • Prized for eggs = cavier • Caspian and Black Seas of western Asia • Stock collapsing (Asian) • Shovelnose sturgeon and pallid sturgeon • Very fecund; mature at a late age

10. Acipenseriformes: • Paddlefish: • Lack bony scutes; long rostrum • 2 genera : American (Polyodonspathula) • Chinese Paddlefish (Psepherusgladius) • American: “Spoonbill cat” • Mississippi, Ohio, and Missouri Rivers • Planktivore; Long, narrow gill rakers • Up to 2m long; 75 kg • Rostrum: electrosensory function? • -- rooting through sediment?

11. Acipenseriformes: • Paddlefish: • Chinese(Psepherusgladius): • Yangtze River system • Smaller rostrum • Presumed piscivorous • Danger of extinction: • Dam construction • overfishing

12. Semionotiformes: Gars • Thick ganoid scales • Bony head and snout • Long jaws with strong sharp teeth • Spiral valve intestine • Gas bladder divided internally • Dorsal an anal fins set far back on body

13. Semionotiformes: Gars • Primitive predators • N. America • 1 species in Cuba • All but one freshwater • Alligator gar occasionally enters SW • Gas bladder divided internally • Dorsal an anal fins set far back on body

14. Order Ammiiformes • One species, the bowfin (Amia calva) • Heterocercal tail • Rudimentary spiral valve intestine • Cycloid scales • Physostomous gas bladder

15. Order Ammiformes • Bowfin: • Predatory species • Sucks prey into its mouth (canine teeth) • Swims via undulations of long dorsal fin • Gulping air for surviving low O2 waters • Males build and defend nests • Defends young until • they are 10 cm long • Edible? …depends!

16. Not as primative, but still “old”

17. Division Teleostei • Cycloid or ctenoid scales (when present) • Lack of spiral valve intestine • three or four lower jaw bones per side

18. Primitive vs. Advanced Traits Elongated bodies with 50-60 vertebrae Deeper bodies with 20-30 vertebrae Single dorsal fin towards Multiple dorsal fins beginning middle or posterior of body more anterior Fins with soft rays only Fins with spines and soft rays Pectoral fins ventral Pectoral fins high on sides of body Pelvic fins towards posterior Pelvic fins below pectorals Premaxilla and maxilla involved Maxilla limited to angle of jaw, in gape of jaw and bare teeth does not bare teeth Non-protrusible jaw Protrusible Jaw Physostomous gas bladder Physoclistous gas bladder Separate Liver and Pancreas Hepatopancreas Cycloid scales Ctenoid Scales

19. Division Teleostei • Divided into 4 groups: • Osteoglossomorpha – bonytongues, mooneyes • Elopomorpha – tarpons and eels • Clupeomorpha – herrings • Euteleostei – everything else

20. Subdivision Osteoglossomorpha • Mostly tropical species of Africa, Asia, and South America • Some have enhanced electrosensory abilities • (REM: elephantfish and knifefish...same group) • Used as food & some angling • Many aquarium species • Examples: • Arawanas – popular aquarium fish • Mooneye – herring-like fish from the Great Lakes Region. Some value as sport and food fish

21. Arawana

22. Mooneye Hiodon tergisus

23. O. Elopiformes – tarpon, ladyfish, bonefish • important recreational species • No market for meat • Sought for large size and active fighting habits

24. Order Anguilliformes – eels • 20 families of eels • Elongated bodies with large number of vertebrae • Pectoral fins reduced in size • Pelvic fins absent • Scales: small or absent

25. Orders Anguiliformes • Suborder Anguilloidei • Suborder Muranoidei • Suborder Congroidei • American, European and Japanese eels (Anguilla) • Catadromous – spawn in SW, mature in FW • American and European eels: • Spawn in deep waters in central N. Atlantic • Leptocephali drift with current • Transform into threadlike elvers • Ascend rivers and spend several years there maturing

26. Order Saccopharyngiformes – eels • Group of bizarre deep-sea fishes • Includes: • Gulper eels • Snipe eels

27. Clupeiformes • Herrings and anchovies • Important food fishes • Large silvery scales • Soft rays only • Large easily shed cycloid scales

28. Basically, this gizzard shad is a freshwater menhaden!

29. Order Clupeiformes • Large scale fisheries exist for marine species • Some consumed by humans • Used in animal feeds and fertilizers • Population dependent on plankton abundance which is dictated by ocean circulation • Upwelling of cold nutrient rich water • Nutrients phytoplankton bloom zooplankton anchovies • El Niño

30. Euteleostei: Superorder Ostariophysi • Possess “Webberian Apparatus” • - modified anterior vertebrae and special bony connections between gas bladder and ear • Contains: • - minnows • - suckers • - tetras • - catfishes

31. Euteleostei: Superorder Ostariophysi • Order Gonorhynchiformes • Order Cypriniformes • Family Cyprinidae • Family Catastomidae • Order Characiformes • Order Siluriformes • Order Gymnotiformes

32. Euteleostei: Superorder Ostariophysi • Order Gonorhynchiformes • milkfish (Chanos chanos) • Important aquaculture species in SE Asia • Raised in earthen ponds • Important source of animal protein

33. Euteleostei: Superorder Ostariophysi • Order Cypriniformes: • Family Cyprinidae: - Jaw Teeth Absent - Adipose Fin Absent - Barbels Present Eurasia - N. America and - Base forage

34. Euteleostei: Superorder Ostariophysi • Order Cypriniformes: • Family Cyprinidae: • Grass Carp: • Introduced species • Herbivore • Eradicates vegetation • Illegal to stock or sell diploids • Triploids acceptable

35. Cyprinidae; Minnows

36. Euteleostei: Superorder Ostariophysi • Order Cypriniformes: • Family Catastomidae: • suckers • Fleshy protrusible lips • White and spotted suckers • Buffalo fishes • Redhorses • Quillbacks • carpsuckers

37. Euteleostei: Superorder Ostariophysi • Order Characiformes: - Jaw Teeth Present - Adipose Fin Present - Barbels Absent America, and Africa - S. America, C.

38. Charachidae: Tetras

39. Siluriformes • Lack Scales, often with bony plates on head or body • Teeth present on premaxillary, absent on maxillary • Many have venomous “spines” composed of fused soft rays • - venom gland at base of spine

40. Siluriformes • Well developed sensory barbels • Usually an adipose fin • Found on all continents except Antartica • Some marine (gafftop and sea catfish) • Greatest diversity in S. America • Important food source • Important game and aquarium fishes

43. Gymnotiformes • Unusual electrical fishes • South and Central America • Elongated bodies and small eyes • Sometimes called S. American knifefishes • Modified muscle tissue for production of electrical fields • Electric eel (produce more than 500 volts)

44. CHAPTER 18 Class Osteichthyes Infradivision: Euteleostei Minnows, Characins, and Catfishes True teleosts

45. Suberorder: Ostariophysi 6500 species Dominant freshwater fishes Some of most important aquaculture species

46. Suberorder: Ostariophysi Six Characteristics of group • Have fright substance (Schreckstoff) released into water when fish is injured • Swimbladder is present and usually has two chambers • Unculi present: small unicellular projections on body that may provide rough surface for clinging or scraping • Breeding tubercles well developed • Upper jaw (premaxilla) easily extended for suction feeding • Pelvic fins abdominal in position

47. Order: Gonorynchiformes • Toothless mouths • Epibranchial organs (modified gill rakers for breaking up ingested food

48. Family Chanidae Milkfish • Marine and brackish water species • One of most important food fishes of Southeast Asia • Adults to 1.8 m • Silvery sides • Deeply forked tails

49. Milkfish Chanos chanos

50. Order Cypriniformes • Dominate freshwter fishes of North America and Eurasia • 2700 species • Most possess protractile mouths without teeth • Most posses pharyngeal teeth • Heads lack scales (with few exceptions) • All lack adipose fins