Class Actinopterygii and Class Sarcopterygii

1. Biology 2 : Zoology
Rey John B. Rebucas
USeP (Tagum)-BEEd

2. SARCOPTERYGII:
Lobe-finned fish
ACTINOPTERYGII:
Ray-finned Fish

3.  General
Description
 Characteristics
 Classification

4. ACTINOPTERYGII:
Ray-finned Fish

5. GENERAL DESCRIPTION
Ray-finned Fishes
 Greek: aktis=ray + pteryx =fin/wing
 Contain all the familiar bony fishes –
more than 23,600 species.
 More than 50 % of known fishes.
 Teleosts make up 96% of all living
fish.
 Swim bladder moved away from any
function for respiration, used only for
buoyancy.
 Fins are flexible, controlled by
muscles in body, fins are supported by
spines rather than bones.

6. GENERAL DESCRIPTION
Morphological Trends
 Heavy dermal armor replaced by light, thin, flexible
cycloid and ctenoid scales.
Increased mobility helps fish avoid predators and
in food getting.
Some eels, catfishes and others completely lost
scales.
 Fins changed to provide greater mobility and serve a
variety of functions: braking, streamlining and social
communication.
 The homocercal tail allowed greater speed and
buoyancy.
 The swim bladder shifted from primarily respiratory
to buoyancy in function.
 The jaw changed to increase suctioning and
protrusion to secure food.

7. BASIC FISH ANATOMY
Internal

8. BASIC FISH ANATOMY
External

9. OUTER COVERING
 Mucus – reduces friction and prevents
infection
 Scales – protective outer cover
Overlap like roof shingles
Can tell age of fish

10. TYPES OF OUTER COVERING
Ganoid- diamond shaped
Placoid- cartilaginous fishes
Ctenoid- comb-like ridges
Cycloid-light, thin, & flexible
Myomeres-zigzag bands

11. CLASSIFICATION
1. CHONDROSTEANS
 have heterocercal tails and
ganoid scales like the
sturgeons.

12. CLASSIFICATION
2.NEOPTERYGIANS
One lineage of early
neopterygians led to the
modern bony fishes
(teleosts).
Early type neopterygians
include the bowfin and
gars.

13. CLASSIFICATION
2.1
SEMIONOTIFORMES
(Lepisosteiformes)
 ganoid scales
 abbreviated heterocercal tail
 intestine with spiral valve
 lung-like gas bladder
2.2 AMIIFORMES
(Amia calva)
 ganoid scales
 abbreviated heterocercal
tail
 intestine with spiral value

14. CLASSIFICATION
• 2.3 TELEOSTS
 Fins diversified for a variety of functions:
camouflage, communication, complex
movements, streamlining, etc.

15. SARCOPTERYGII:
Lobe-finned Fish

16. GENERAL DESCRIPTION
This group was much more abundant during the
Devonian period.
Rhipidistians are an extinct group of sarcopterygians
that led to tetrapods.

17. GENERAL DESCRIPTION
 Name means “fleshy finned fishes”
 First appeared 385 million years ago
 Ancestors of land vertebrates!
 Internal nostrils and cosmoid scales.

18. GENERAL DESCRIPTION
 Some lungfishes can live out of the water for long periods of
time.
 During long dry seasons, the African lungfish can burrow
down into the mud and secrete lots of slime forming a hard
cocoon where they will estivate until the rains return.

19. BASIC FISH ANATOMY
 Bony leg-like supports, external to body.
Pectoral fin
Pelvic fin

20. BASIC FISH ANATOMY
 All early sarcopterygians had lungs as well as gills and a
heterocercal tail.
Later sarcopterygians have a continuous flexible fin
around the tail.
 They have fleshy, paired lobed fins that may have been
used like legs to scuttle along the bottom.

21. CLASSIFICATION

22. CLASSIFICATION
1.CROSSOPTERYGII/COELACANTHIMORPHA
 “Coelacanths”
 Cosmoid scale
 Two dorsal fins and fleshy paired fins with skeletal
elements.
 Thought to be extinct till found
 Sometimes grouped with lungfish in Subclass
Sarcopterygii.

23. CLASSIFICATION
 First discovered by Marjorie Courtenay-Latimer year
1939 and she named it Latimeria chalumnae (“Old
fourlegs”).
 Secondly discovered by J. L. B. Smith the 2nd specie in
1952.
 Comoro Islands (now Kenia, Madagascar, South
Africa…)
 Mark Erdmann conducted a genetic study through live
observations in Indonesia (Sulawesi), 1998 after his
successful discovery he named it Latimeria
menadoensis (“King of the Sea”).

24. CLASSIFICATION
2. DIPNOI
 “Lungfish”
 Jaw fused to brain case
 Caudal, dorsal, and anal fin connected
 Pectoral fins long and tubular
 Air breathing organ attached to esophagus

25. CLASSIFICATION
3. OSTEOLEPIMORPHA - EXTINCT
 Sister group of modern tetrapods
 Similar fins to Devonian Amphibians limbs
 Other morphological similarities

26.  Habitat
 Locomotion
 Mode of Nutrition
 Characteristics
 Reproduction

27. HABITAT
 SARCOPTERYGIANS are mostly found in river mouths near
the oceans (estuaries) and also in the freshwater habitats like
lakes.
 ACTINOPTERYGIANS inhabit a variety of extreme environ-
ments. These include high altitude lakes and streams, desert
springs, subterranean caves, ephemeral pools, polar seas, and
the depths of the ocean, mudflat habitats, hill stream loaches
and steep, torrential watercourses of Asiatic hillstreams (C.
Patterson, 1981).
 Across these habitats water temperatures may range from -
1.8˚C to nearly 40˚C, pH levels from 4 to 10+, dissolved oxy-
gen levels from zero to saturation, salinities from 0 to 90 parts
per million and depths ranging from 0 to 7,000 m (Davenport
and Sayer 1993 in Moyle and Cech 2004:1).

28. LOCOMOTION
 Speed
 Most fishes swim maximally at ten body lengths per
second; a larger fish therefore swims faster.
 Fishes use trunk and tail musculature to propel them through
the water.
 Many fast swimmers are streamlined with grooves so their fins
can lie flat.

29. LOCOMOTION
 Nektonic – swimmers control movement against current
 Move to food
 Escape predator
 Streamlining to reduce drag = teardrop
shape =fusiform
 Most fish swim by moving tail side to side
 Mucous reduces drag
 Homocercal tail – top and
bottom same size

30. BOUYANCY
 The energy cost per kilogram of body
weight for traveling one kilometer is
0.39 Kcal for swimming, 1.45 Kcal
for flying and 5.43 for walking.
 Flexible fishes like eels use a
serpentine movement.
 Not very efficient for high speed.
 Fast swimmers are less flexible.
 Body undulations limited to caudal
region.
 The heterocercal tail provides lift
as it moves from side to side.

31. BOUYANCY
 Gas-filled swim bladder – to maintain
position in water
 Control quantity of gas
 Not present in fast moving fish or sharks
 A fish can control depth by adjusting
the volume of gas in the swim
bladder.
 Due to pressure, as a fish descends,
the bladder is compressed making the
total density of the fish greater.
 As a fish ascends, the bladder
expands making the fish lighter and it
will rise ever faster.

32. BOUYANCY
 Gas may be removed in two ways: Physostomous and
Physoclistous.
 Physostomous fishes (more primitive, e.g. trout) have a
pneumatic duct that connects the swim bladder and the
esophagus.
 Air can be expelled through the duct.
 Gas must be secreted into the swim bladder from the blood,
although some species can gulp air to fill the swim bladder.
• Physoclistous fishes (more derived, e.g. advanced teleosts) the
pneumatic duct has been lost. Gas must be absorbed by blood
from the highly vascularized ovale.
– Gas is secreted into the swim bladder from the blood at the
gas gland.

33. OSMOTIC REGULATION
 Freshwater fishes
(hyperosmotic regulators) must
have a way to get rid of water
that enters their bodies by
diffusion through the gills.
Water enters the body, salts
are lost by diffusion.
Water is pumped out by the
opisthonephric kidney which
can form very dilute urine.
Salt absorbing cells in the
gill actively move salt from
the water into the blood.

34. OSMOTIC REGULATION
 Saltwater fishes (hypoosmotic
regulators) have a lower blood
salt concentration than the
seawater.
 Tend to lose water and gain
salts.
 Marine teleosts drink
seawater.
 Salts are carried by the blood
to the gills where they are
secreted out by salt-secretory
cells.
 Other salts are voided with
feces or excreted by the
kidney.

35. CHARACTERISTICS
HEARING
 The bodies of fishes are nearly
the same density as water.
 Makes hearing difficult.
 Weberian ossicles, found in
minnows, suckers, & catfish,
improves hearing.
 Sound detection starts in swim
bladder (sound vibrates easily
in air) and is transmitted to the
inner ear by Weberian ossicles.

36. CHARACTERISTICS
VISION
 Obtain better vision
 Fish eyes focus by moving
closer or farther away from
subject
 Many have color vision

37. CHARACTERISTICS
LATERAL LINE SYSTEM
Line of pores and canals running down body.
Detect vibrations, changes in current direction and
water pressure.

38. CHARACTERISTICS
RESPIRATION
 Fish gills are composed of thin
filaments covered with an epidermal
membrane that is folded into lamellae.
 Richly supplied with blood vessels.
 Located inside the pharyngeal
cavity.
 Covered with an operculum in
bony fishes.

39. CHARACTERISTICS
RESPIRATION
 Water must be continuously
pumped over the gills.
 A countercurrent system
is found where the flow of
water is opposite to the flow
of blood.
Deoxygenated blood
encounters the freshest
water with the highest
oxygen content.

40. CHARACTERISTICS
PROTECTION
 Camouflage
ex. sargassum fish
 Spines
ex. blow fish
 Countershading
ex. tuna fish
 Disappear
ex. flying fish
 Deceptive markings
ex. butterfly fish

41. CHARACTERISTICS
SCHOOLING
¼ of all species at some point
in life
Looks like one large individual
Confuses predator
Hard to catch one fish
Easier feeding
Easier mating
No leaders

42. MODE OF NUTRITION

43. MODE OF NUTRITION
 Most fishes are CARNIVORES and prey on everything from
zooplankton to large vertebrates.
 Some deep-sea fishes can eat victims twice their size – an
adaptation to scarce food.
 Most fishes can’t chew with their jaws (this would block
water flow over the gills), many have pharyngeal teeth in
their throats.
 Large-mouthed predators can suck prey in by suddenly
opening their mouths.

44. MODE OF NUTRITION
 HERBIVOROUS fishes eat
plants and micro-algae.
 Most common on coral reefs –
parrotfishes, damselfishes and
etc.
 And tropical freshwater
habitats – minnows, characins,
catfishes.
 Grazers – fish that feed primarily
on seaweeds and other plants
 Some develop beaks to help scrape
off algae or pieces of coral

45. MODE OF NUTRITION
 Suspension feeders filter microorganisms
from the water using gill rakers.
 Herring-like fishes are common –
menhaden, herring, anchovies etc.
 Many larval fishes.
 Most are pelagic fishes that travel in large
schools.
 Other groups are scavengers that eat dead
and dying animals.
 Detritivores that consume fine particulate
organic matter.
 Parasites that consume parts of other live
fishes.

46. REPRODUCTION
 The four major types: monogamy,
polygyny, polyandry and polygy-
nandry or promiscuity - both
males and females have multiple
partners during the breeding sea-
son.
 Most fishes are dioecious with
external fertilization and
external development –
oviparity.
 Ovoviviparous species (guppies,
mollies, surfperches) bear live
young after development in the
ovarian cavity of the female.

47. REPRODUCTION
 Fertilized eggs may be pelagic
and hatch into pelagic larvae.
 Large yolky benthic eggs are
often attached to vegetation or
deposited in nests, buried, or even
carried in the mouth.
Many benthic spawners guard
their eggs.
Usually the male.

48. REPRODUCTION
 In some species, males defend nest sites and
perform courtship rituals to entice females
to lay their eggs in his nest. Sometimes,
several females will lay eggs in a nest.
 The male will guard the eggs from
predators and will also fan them with his
fins to aerate them.
 Separate sexes
 External fertilization = spawning
 Female releases eggs
 Male releases sperm on top

49. MIGRATION OCEANODROMOUS- fishes that stay within saltwater
 POTAMODROMOUS- fishes that stay in fresh water in their
entire lives.
 DIADROMOUS- fishes that migrate between the salt and
fresh water as part of their life cycle (to reproduce) or to feed.
 ANADROMOUS- growth occurs primarily in saltwater but
move into freshwater to spawn like salmons.
 CATADROMOUS- growth occurs primarily in freshwater
but move into saltwater to spawn like anguilid eels.
 AMPHIDROMOUS- migrate between salt and fresh water
for spawning and feeding purposes like gobies and sleepers.

50. REFERENCES
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Cummings. New York. 2009.pp. 688

51. REFERENCES Clack, J. A. 2002. Gaining Ground: The Origin and Evolution of Tetrapods.
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52. Thank
You
And
God Bless