Transcript Diversity of Fishes III

Diversity of Fishes III
Fish Taxa Diversity
• Phylum Chordata
– Superclass Agnatha
• Class Pteraspidomorphi †
• Class Myxini (?)
• Class Cephalaspidomorphi
– Superclass Gnathostomata
• Class Placodermi †
• Class Chondrychthyes
• Class Acanthodii †
• Class Sarcopterygii
• Class Actinopterygii
Evolution of Fishes
Superclass Gnathostomata (still)
• Class Acanthodii † (“spiny sharks”)
– Cartilaginous skeletons with ossified
pieces & characteristic spines
– Pelagic habitat (FW & SW)
– Considered sister group of bony fish
Teleostomi or Osteichthyes
(Bony Fishes)
Sarcopterygi
Actinopterygi
Superclass Gnathostomata
• Class Sarcopterygii (lobed fins)
– Coelacanths and lungfishes
– Osteolepimorphi †
• Class Actinopterygii (ray fins)
- Ray finned fishes
Class Sarcopterygii
• Order Coelacanthiformes
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Family Coelacanthidae (coelecanths)
Fleshy lobed fins
Characteristic osteological features (fig 13.6)
Choanae (internal nostrils)
2 spp.
Latimeria chalumane
(“Old fourlegs”)
• Marjorie Courtenay-Latimer (1939)
• J. L. B. Smith
– 2nd specimen (1952)
• Comoro Islands (now Kenia, Madagascar,
South Africa…)
• French embargo
• Conservation issues
• Live observations (nocturnal, 200m)
• Ovoviviparous
Latimeria menadoensis
(“King of the Sea”)
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Mark Erdmann (1998)
Indonesia (Sulawesi)
Conservation issues
Genetics study
Live observations
Other Coelacanth Locations?
Meso-american
silver jewelry
1800’s
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Class Sarcopterygii
• Infraclass Dipnoi (lungfishes)
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Massive toothplates
Maxillae and Premaxillae bones missing
Functional Lung, choanae (internal nostrils)
Family Ceratodontidae (Australia, 1spp.)
Family Lepidosirenidae (S. America, 1spp.)
Family Protopteridae (Africa, 4 spp.)
Ceratodontidae
Australian lungfish
Neoceratus forsteri
Lepidosirenidae
S. American lungfish
Lepidosiren paradoxa
Protopteridae
African lungfishes
Protopterus sp.
Class Sarcopterygii
• Infraclass Osteolepimorphi †
– Sister group of modern tetrapods
– Similar fins to Devonian Amphibians limbs
– Other morphological similarities
Teleostomi or Osteichthyes
(Bony Fishes)
Sarcopterygi
Actinopterygi
Class Actinopterygii
Class Actinopterygii
TELEOSTEI
Class Actinopterygii
• Order Polypteriformes
– Family Polypteridae (bichirs & reedfish)
• 10 spp. (African rivers)
• Facultative airbreathers (spiracle exhalation)
• Lobed fins, ganoid scales, heterocercal tail, spiral
intestine.
• Flagfins (vertical spine with horizontal rays)
Class Actinopterygii
• Order Acipenseriformes (secondary
cartilaginous skeleton, heterocercal tail, fin rays, spiral
valve intestine). Sturgeons and Paddlefish
– Family Acipenseridae (sturgeons)
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24 spp. (northern hemisphere)
5 rows bony scutes (modified ganoid scales)
4 barbels in front of ventral mouth
Fresh water spawning (typically Anadromous)
Class Actinopterygii
• Order Acipenseriformes (secondary
cartilaginous skeleton, heterocercal tail, fin rays,
spiral valve intestine)
– Family Polyodontidae (paddlefishes)
• 2 spp. (N. American and Chinese
paddlefishes)
• No bony scutes, small scales, ossified head
plates
• Freshwater open water plankton feeders
• Paddle as electroreceptor?
Class Actinopterygii
• Order Semionotiformes
– Family Lepisosteidae (garfish)
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7spp. (North and Central America)
Ossified skeleton
Ganoid scales
Slightly heterocercal caudal fin
Backwaters in lakes and rivers, predatory fish
Toxic eggs
Class Actinopterygii
• Order Amiiformes
– Family Amiidae (bowfin)
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1 spp. (Amia calva, Eastern North America)
Ossified skeleton
Slightly heterocercal caudal fin
Cycloid scales
Swims through dorsal fin ondulations
Backwaters in lakes and rivers