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-coelocanths, lungfish

4. Acipenseriformes: • Cartilaginous skeletons lacking vertebral centra • 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

5. 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

7. 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 in length; 75 kg • Rostrum: electrosensory function? -- rooting through sediment?

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

9. 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

10. 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

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

12. 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!

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

14. Primitive vs. Advanced Traits

15. Primitive vs. Advanced (continued)

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

17. Subdivision Osteoglossomorpha • Mostly tropical species of Africa, Asia, and South America • Have enhanced electrosensory abilities • Some used as food • Mostly aquarium species • Examples: • Arrowannas – popular aquarium fish • Mooneye – herring-like fish from the Great Lakes Region. Some value as sport and food fish

20. Subdivision Elopomorpha • Characterized by leptocephalus larva • Long and laterally compressed • Evidence of phylogenetic affinity with eels • Order Elopiformes • Order Anguiliformes • Suborder Anguilloidei • Suborder Muranoidei • Suborder Congroidei • Order Saccopharyngiformes

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

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

23. Elopamorpha • Suborder Anguilloidei • 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

24. Elopamorpha • Suborder Muraenoidei • Moray eels of tropical oceans • Lack pectoral fins • Some have venomous bite

25. Elopamorpha • Suborder Congroidei • Large group of marine eels • Some used for food

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

27. Subdivision Clupeomorpha • Herrings and anchovies • Important food fishes • Silvery, compressiform fishes • Large silvery scales

28. Subdivision Clupeomorpha • Soft rays only • Large easily shed cycloid scales • Bony scutes on ventral and sometimes dorsal surfaces • Gas bladder extends anterior into the skull (otophystic) • Helps transmit low frequency sounds to the ear

29. SubdivisionClupeomorpha • Order Clupeiformes • Mostly marine planktivores • - some freshwater, anadromous, and predatory forms • Extremely high biomass • Important role in food chain • - gizzard and threadfin shad typicallystocked as a forage base for pike and largemouth bass,

31. 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

32. SubdivisionEuteleostei • Encompasses all remaining fish • Large assemblage of fishes • Possess more advanced characteristics

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

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

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

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

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

38. Cyprinidae; Minnows

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

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

41. Charachidae: Tetras

42. 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

43. 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

46. 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)

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

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

49. 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

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