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Comparative Anatomy Vertebrate Phylogeny: Fishes Kardong Chapter s 2 & 3 Part 4 Vertebrate Classification Geological Eras of early vertebrates Paleozoic (oldest ... – PowerPoint PPT presentation

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Title: Comparative Anatomy Vertebrate Phylogeny: Fishes


1
Comparative AnatomyVertebrate Phylogeny Fishes
Kardong Chapter s 2 3 Part 4
2
Vertebrate Classification
Figure 4.1a
  • Geological Eras of early vertebrates
  • Paleozoic (oldest) see figure 4.1b
  • Mesozoic
  • Cenozoic

3
Figure 4.1b.
4
Cambrian Period
  • Ostracoderms- first vertebrates, bony skin
  • Class Agnatha- jawless fish
  • No paired fins
  • Bony exoskeleton with
  • dermal armor
  • Ex hagfish and lampreys
  • Jawed fish evolved from Ostracoderms in Silurian
    period

(a)
(b)
Figure 4.2. (a) ostracoderm, (b) ostracoderm,
and (c) lamprey.
(c)
5
Chordate Origins Lower to Higher Organisms
  • Echinoderm ancestor (deuterostomes) gave rise to
    vertebrates
  • Deuterostomes- blastopore gives rise to anus
  • Protostomes- blastopore gives rise to mouth

Figure 4.3. (above) protostomes and (b)
deuterostomes.
6
Gnathostomes Placoderms
  • Class Placodermi
  • Jawed and paired fins
  • Bony dermal exoskeleton armored fish
  • 1st jaws were large
  • Jawed fishes gave rise to all other fishes
  • Age of fishes- Devonian Period

Figure 4.4. Armored fish.
Figure 4.5. Mandibular (ma) and hyoid (hy)
arches develop in gnathostomes into
palatoquadrate (pq) and Meckels (Mc) cartilages
7
Fish Evolution
(a)
(b)
Figure 4.6. (a) jawless fish, (b) early jawed
fish, and (c) modern jawed fish.
(c)
8
Placoderms
  • Anadromous- fish move to freshwater to breed
  • Catadromous- fish move from freshwater to breed
  • Hypothesized function of bone to provide
    calcium for muscle contraction

Figure 4.7. Craniates through geological time
(Book figure 3.1).
9
Cartilagenous Fishes
  • Chondrichthyes
  • Cartilaginous skeleton
  • Bone remains in scales - placoid scales
  • Teeth are modified scales
  • Ex elasmobranchs (sharks, rays skates,) and
    the holocephalans (chimaeras-ratfishes)

Figure 4.8. Basking shark-second largest fish.
10
Elasmobranchii vs Holocephali
Figure 4.9. (Book figure 3.13).
11
Tail Type
  • Heterocercal- vertebral axis curves upward two
    asymmetrical lobes (dorsal portion larger)
  • More primitive, some bony fish
  • Ex sharks
  • Homocercal- symmetrical dorsal and ventral lobes
  • Most common
  • Ex perch
  • Diphycercal- spear shaped
  • Ex lungfish, crossopterygians

Figure 4.10. Tail types.
12
Class Osteichthyes
  • Subclass Actinopterygii (ray-finned)
  • Chondrostei- most primitive heterocercal tail
  • Ex sturgeon, paddlefish, Polypterus
  • Holostei- dominant in past heterocercal tail
  • Ex gar, bowfin
  • Teleostei- dominant today homocercal tail
  • Majority of all fish

Figure 4.11. Venomous lionfish (actinopterygian).
13
Figure 4.12.
  • Evolutionary relationship of vertebrates with
    jaws (Gnathostomata) to those with bony skeleton
    (Osteichthyes)

14
Class Osteichthyes (cont.)
  • Subclass Sarcopterygii (fleshy or lobe finned)
  • 3 genera of lungfish are found on 3 separate
    continents
  • Continental Drift
  • Torpidity- inactivity hibernation
  • Aestivation- burrow through dry season
  • Order Dipnoi
  • Order Crossospterygii

Figure 4.13. Aestivation fish burrows into mud
until rain returns. (see Box Figure 1, p . 101).
15
Early Sarcopterygians
Figure 4.14. Early Devonian fishes, including
the newly described Tiktaalik (an intermediate
link between fishes and land vertebrates). (Book
figure 3.20.).
16
Order Crossopterygii
  • Living fossil fish
  • Species thought to be extinct until coelacanth
    (Latimeria) discovered.
  • Found off coast of South Africa in 1938
  • May be a separate species discovered off
    Indonesia in 1999

Figure 3.15. Global locations of coelacanth
discoveries.
17
Coelacanth
Figure 3.16. Coelacanth in Indian Ocean.
18
Coelacanth
Figure 4.17. Coelacanth.
Figure 4.18. Africas Sundaytimes-political
humor.
19
Figure 4.19. Labyrinthodont (primitive tetrapod).
  • Crossopterygiians (lobe-finned fish) gave rise
    to labyrinthodonts (early tetrapods)
  • in Devonian Period

20
Linking Morphology
  • Limbs
  • Vertebrae
  • Girdles similar
  • Fins skeletal composition exhibits homology with
    early tetrapods
  • Amphibian diversity during Carboniferous period
  • Toward reptiles, Anura, Caudata, and Apoda.

Figure 4.20.
Figure 4.21.
21
More Linking Evidence
  • Skulls flattened with homologous bones
  • A chiridium muscular limb with well-defined
    joints and digits
  • Parietal foramen
  • Crossopterygian skull shows place for third eye
  • Third (pineal) eye visible in young reptiles
    (e.g., tautara)
  • Tooth structure
  • Labyrinthodont tooth

Figure 4.22. Crossopterygian skull.
Figure 4.23. Grooved tooth.
22
Lissamphibia Modern Amphibians
  • Apoda - caecilians
  • Long and slim segmented rings
  • Dermal bones (scales) embedded in annuli

Figure 4.24. Caecilian showing annular body
rings.
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