1. Where we started…
Myxiformes
Petromyzontiformes
Gnathostomata

2. Gnathostomata
Holocephali
Elasmobranchi
Sarcopterygii
Actinopterygii

3. Actinopterygii
Acipenseriformes
Semionotiformes
Amiiformes
Teleostei

4. Teleostei
Osteoglossomorpha
Elopomorpha
Clupeomorpha
Ostariophysi

5. Superorder: Ostariophysi
64% of freshwater species!
Weberian apparatus

6. Superorder: Ostariophysi
Schreckstoff signals
Schreckreakton

7. Ostariophysi Gonorhynchiformes Cypriniformes Characiformes
Siluriformes
Gymnotiformes

8. Gonorhynchiformes 35 species Have Schreckstoff signals
Don’t have Weberian apparatus
Do have modified first 3 vertebrate
Secondary loss of gas bladder

9. Cypriniformes Largest order- 2660 species!
Emergence of pharyngeal dentition

10. Cypriniformes Some are polyploidy
Linked with large size in minnows
Smallest freshwater fish in the world
Catlocarpio siamensis
Diploid #: 98
Paedocypris progenetica
7.99 mm

11. Algae eaters Gyrinocheilid Suckers (Catostomidae)
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

12. Family Cobitidae (Loaches)
110 species
Benthic
Size: from inches
Predominantly Eurasian, with the highest diversity in Southeast Asia.
Include popular aquarium species:
Kuhli
Clown
Skunk Loaches
Golden Dojo
*Weatherfish*

13. 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 exchange then occurs

14. 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

15. Order Characiformes 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

16. Anatomically and Ecologically Diverse
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)

17. 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
Popular Aquarium Fish:
Headstanders
Spraying characins
Freshwater hatchetfishes
Blind characins
Pencilfish
Tetras
Silver dollars

18. 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

19. 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

20. Piranha and Weatherfish Videos

21. 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?

22. Picture Credits