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Where we started…
Myxiformes
Petromyzontiformes
Gnathostomata
Gnathostomata
Holocephali
Elasmobranchi
Sarcopterygii
Actinopterygii
Actinopterygii
Acipenseriformes
Semionotiformes
Amiiformes
Teleostei
Teleostei
Osteoglossomorpha
Elopomorpha
Clupeomorpha
Ostariophysi
Superorder: Ostariophysi
• 64% of freshwater species!
• Weberian apparatus
Superorder: Ostariophysi
• Schreckstoff signals
• Schreckreakton
Ostariophysi
Gonorhynchiformes
Cypriniformes
Characiformes
Siluriformes
Gymnotiformes
Gonorhynchiformes
• 35 species
• Have Schreckstoff signals
• Don’t have Weberian apparatus
– Do have modified first 3 vertebrate
• Secondary loss of gas bladder
Cypriniformes
• Largest order- 2660 species!
• Emergence of pharyngeal
dentition
Cypriniformes
• Some are polyploidy
– Linked with large size
in minnows
Catlocarpio siamensis
Diploid #: 98
• Smallest freshwater
fish in the world
Paedocypris progenetica
7.99 mm
Algae eaters
• Gyrinocheilid
– Water inhaled dorsally, exhaled ventrally
• Suckers (Catostomidae)
– Mostly benthic and live in lotic system feeding on
algae and periphyton
– Lake suckers (Chasmistes) planktivores with terminal
mouths
– Difficult for taxonomists
Chasmistes cujus
Family Cobitidae (Loaches)
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110 species
Benthic
Size: from 2.5-12 inches
Predominantly Eurasian, with the highest
diversity in Southeast Asia.
• Include popular aquarium species:
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Kuhli
Clown
Skunk Loaches
Golden Dojo
*Weatherfish*
Weatherfish (Misgurnus)
• Reason for name:
– Become restless when
atmospheric pressure
drops preceding a
storm
• Could be due to their air
breathing abilities
– Gulp atmospheric air
and pass it as a
bubble to the
intestine, gaseous
http://www.loaches.com/species-index/weather-loach-misgurnis-anguillicaudatus
exchange then occurs
• Balitorid river and
hillstream loaches
– Specialized for living in
fast-flowing water
• Streams of India and
Southeast Asia
– Have paired fins that
oriented horizontally
• Adhesive pads on
ventral surfaces
– Bodies depressed
dorsoventrally
– Mouths are ventral
http://www.loaches.com/articles/hillstream-loaches-the-specialists-at-life-in-the-fast-lane
Order Characiformes
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1340 species
10 families are recognized
Order has and is undergoing taxonomic revision
1150 Species found in South America, 200 in
Africa, a few in Central America, one (Mexican
Tetra) extends into Southwest Texas.
• 10 species (including piranhas) have been
introduced in the US
• Characterized by:
– Adipose fin
– Well-armed mouths
– Replacement Dentition
– Ctenoid scales
• Anatomically and Ecologically Diverse
– Predators
– Zooplanktivores
– Scale eaters
– Detritivores
– Hebivores (feed on seeds, leaves and fruits)
• Can be surface, water column, or
benthic dwellers
– Most prefer mid-water and many are in
shoals
• Large range of body sizes:
– From 13-mm adult tetras to 1.5 m
tigerfishes
– Can be long and slender or deep-bodied
and compressed
http://www.aquafish.net/imgs/fish/silver-dollar-2.jpg
• Popular Aquarium Fish:
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Headstanders
Spraying characins
Freshwater hatchetfishes
Blind characins
Pencilfish
Tetras
Silver dollars
http://www.aqua-fish.net/imgs/fish/common-hatchetfish-2.jpg
• Most Primitive Characiforms
– 100 species
• African citharinids (Distichodus, Citharinus)
– African characiforms also include 100 species
of advanced alestiine characids
– African origin for the order
• Connection between Africa and South America
– Prior to break up of Gondwanaland
• Distribution of characiforms could be explained by
vicariance
– Reason for difference in species number between Africa
(~200) and South America (1150)
» South America more open niches? more
speciation
» Africa limited niches? limited speciation
Subfamily Serrasalminae (Piranhas)
• 60 Species
– Some predatory, others scale-eating opportunist and specialist,
and some herbivorous (Pacu and Silver Dollar)
• Herbivorous species are important for two reasons:
– Food fish
– Seed dispersers
• Because of dentition, can break the outer layer of the seed aiding in
germination.
• Needed by plants
• Have undeserved bad reputation
– Many cases didn’t actually kill the people
• Drowned and piranhas picked at the dead body
Piranha and Weatherfish Videos
• http://www.youtube.com/watch?v=AqWzU
Q8lp3M
• http://www.youtube.com/watch?v=EiuNCH
FU_Xg
Questions
• What are 3 advantages and 3 disadvantages to
using Schreckstoff signals that you can think of?
• Explain what has happened to create allow the
evolution of pharyngeal dentition?
• For what evolutionary purpose do you think the
weather fish has developed sensitive to
atmospheric pressure?
• Why do you think larger ploidy numbers reflect
larger organisms?
• What is unique about Balitorid river and
hillstream loaches?
Picture Credits
• http://www.loaches.com/species-index/weatherloach-misgurnis-anguillicaudatus
• http://www.loaches.com/articles/hillstreamloaches-the-specialists-at-life-in-the-fast-lane
• http://www.aqua-fish.net/imgs/fish/commonhatchetfish-2.jpg
• http://www.aqua-fish.net/imgs/fish/silver-dollar2.jpg