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 Smallest freshwater fish in the world Catlocarpio siamensis Diploid #: 98 Paedocypris progenetica 7.99 mm

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

Family Cobitidae (Loaches) 110 species Benthic Size: from 2.5-12 inches Predominantly Eurasian, with the highest diversity in Southeast Asia. Include popular aquarium species: 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 exchange then occurs http://www.loaches.com/species-index/weather-loach-misgurnis-anguillicaudatus

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 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

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)

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 http://www.aqua-fish.net/imgs/fish/silver-dollar-2.jpg 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=AqWzUQ8lp3M http://www.youtube.com/watch?v=EiuNCHFU_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/weather-loach-misgurnis-anguillicaudatus http://www.loaches.com/articles/hillstream-loaches-the-specialists-at-life-in-the-fast-lane http://www.aqua-fish.net/imgs/fish/common-hatchetfish-2.jpg http://www.aqua-fish.net/imgs/fish/silver-dollar-2.jpg